v1.5.0

Return a BuildTarget object from Environment#method_missing when a build target is registered.

README.md

@@ -12,7 +12,7 @@ Add this line to your application's Gemfile:
 
 And then execute:
 
-    $ bundle
+    $ bundle install
 
 Or install it yourself as:
 
@@ -176,9 +176,12 @@ subset of build targets or source files.
 The `build_op` parameter to the build hook block is a Hash describing the
 build operation with the following keys:
 * `:builder` - `Builder` instance in use
+* `:env` - `Environment` calling the build hook; note that this may be
+  different from the Environment that the build hook was added to in the case
+  that the original Environment was cloned with build hooks!
 * `:target` - `String` name of the target file
 * `:sources` - `Array` of the source files
-* `:vars` - `Rscons::VarSet` containing the construction variables to use
+* `:vars` - `Rscons::VarSet` containing the construction variables to use.
   The build hook can overwrite entries in `build_op[:vars]` to alter the
   construction variables in use for this specific build operation.
 
@@ -190,19 +193,96 @@ Rscons::Environment.new do |env|
 end
 ```
 
+### Example: Creating a C++ parser source from a Yacc/Bison input file
+
+```ruby
+Rscons::Environment.new do |env|
+  env.CFile("#{env.build_root}/parser.tab.cc", "parser.yy")
+end
+```
+
 ## Details
 
-### Default Builders
+### Builders
 
-Rscons ships with a number of default builders:
+Rscons ships with a number of builders:
 
+* CFile, which builds a C or C++ source file from a lex or yacc input file
+* Disassemble, which disassembles an object file to a disassembly listing
 * Library, which collects object files into a static library archive file
 * Object, which compiles source files to produce an object file
+* Preprocess, which invokes the C/C++ preprocessor on a source file
 * Program, which links object files to produce an executable
 
 If you want to create an Environment that does not contain any builders,
 you can use the `exclude_builders` key to the Environment constructor.
 
+#### CFile
+
+```ruby
+env.CFile(target, source)
+# Example
+env.CFile("parser.c", "parser.y")
+```
+
+The CFile builder will generate a C or C++ source file from a lex (.l, .ll)
+or yacc (.y, .yy) input file.
+
+#### Disassemble
+
+```ruby
+env.Disassemble(target, source)
+# Example
+env.Disassemble("module.dis", "module.o")
+```
+
+The Disassemble builder generates a disassembly listing using objdump from
+and object file.
+
+#### Library
+
+```ruby
+env.Library(target, sources)
+# Example
+env.Library("lib.a", Dir["src/**/*.c"])
+```
+
+The Library builder creates a static library archive from the given source
+files.
+
+#### Object
+
+```ruby
+env.Object(target, sources)
+# Example
+env.Object("module.o", "module.c")
+```
+
+The Object builder compiles the given sources to an object file.
+
+#### Preprocess
+
+```ruby
+env.Preprocess(target, source)
+# Example
+env.Preprocess("module-preprocessed.cc", "module.cc")
+```
+
+The Preprocess builder invokes either `${CC}` or `${CXX}` (depending on if the
+source contains an extension in `${CXXSUFFIX}` or not) and writes the
+preprocessed output to the target file.
+
+#### Program
+
+```ruby
+env.Program(target, sources)
+# Example
+env.Program("myprog", Dir["src/**/*.cc"])
+```
+
+The Program builder compiles and links the given sources to an executable file.
+Object files or source files can be given as `sources`.
+
 ### Managing Environments
 
 An Rscons::Environment consists of:
@@ -214,10 +294,17 @@ An Rscons::Environment consists of:
 * a collection of targets to build
 * a collection of build hooks
 
-When cloning an environment, the construction variables and builders are
+When cloning an environment, by default the construction variables and builders
-cloned, but the new environment does not inherit any of the targets, build
+are cloned, but the new environment does not inherit any of the targets, build
 hooks, build directories, or the build root from the source environment.
 
+The set of environment attributes that are cloned is controllable via the
+`:clone` option to the `#clone` method.
+For example, `env.clone(clone: :all)` will include construction variables,
+builders, build hooks, build directories, and the build root.
+
+The set of pending targets is never cloned.
+
 Cloned environments contain "deep copies" of construction variables.
 For example, in:
 
@@ -233,8 +320,7 @@ cloned_env["CPPPATH"] << "three"
 ### Construction Variable Naming
 
 * uppercase strings - the default construction variables that Rscons uses
-* lowercase symbols - Rscons options
+* symbols, lowercase strings - reserved as user-defined construction variables
-* lowercase strings - reserved as user-defined construction variables
 
 ### API documentation
 
@@ -243,6 +329,47 @@ http://rubydoc.info/github/holtrop/rscons/frames.
 
 ## Release Notes
 
+### v1.4.3
+
+- fix builders properly using construction variable overrides
+- expand nil construction variables to empty strings
+
+### v1.4.2
+
+- add Environment#expand_path
+- expand construction variable references in builder targets and sources before invoking builder
+
+### v1.4.1
+
+- fix invoking a builder with no sources while a build root defined
+
+### v1.4.0
+
+- add CFile builder
+- add Disassemble builder
+- add Preprocess builder
+- pass the Environment object to build hooks in the :env key of the build_op parameter
+- expand target/source paths beginning with "^/" to be relative to the Environment's build root
+- many performance improvements, including:
+  - use JSON instead of YAML for the cache to improve loading speed (Issue #7)
+  - store a hash of the build command instead of the full command contents in the cache
+  - implement copy-on-write semantics for construction variables when cloning Environments
+  - only load the cache once instead of on each Environment#process
+  - only write the cache when something has changed
+- fix Cache#mkdir_p to handle relative paths (Issue #5)
+- flush the cache to disk if a builder raises an exception (Issue #4)
+
+### v1.3.0
+
+- change Environment#execute() options parameter to accept the following options keys:
+  - :env to pass an environment Hash to Kernel#system
+  - :options to pass an options Hash to Kernel#system
+
+### v1.2.0
+
+- add :clone option to Environment#clone to control exactly which Environment attributes are cloned
+- allow nil to be passed in to Environment#build_root=
+
 ### v1.1.0
 
 - Change Cache#up_to_date?() and #register_build() to accept a single target

lib/rscons.rb

@@ -1,3 +1,4 @@
+require_relative "rscons/build_target"
 require_relative "rscons/builder"
 require_relative "rscons/cache"
 require_relative "rscons/environment"
@@ -5,23 +6,32 @@ require_relative "rscons/varset"
 require_relative "rscons/version"
 
 # default builders
+require_relative "rscons/builders/cfile"
+require_relative "rscons/builders/disassemble"
 require_relative "rscons/builders/library"
 require_relative "rscons/builders/object"
+require_relative "rscons/builders/preprocess"
 require_relative "rscons/builders/program"
 
 # Namespace module for rscons classes
 module Rscons
+  # Names of the default builders which will be added to all newly created
+  # {Environment} objects.
   DEFAULT_BUILDERS = [
+    :CFile,
+    :Disassemble,
     :Library,
     :Object,
+    :Preprocess,
     :Program,
   ]
 
+  # Class to represent a fatal error while building a target.
   class BuildError < RuntimeError; end
 
-  # Remove all generated files
+  # Remove all generated files.
   def self.clean
-    cache = Cache.new
+    cache = Cache.instance
     # remove all built files
     cache.targets.each do |target|
       FileUtils.rm_f(target)
@@ -33,19 +43,85 @@ module Rscons
         Dir.rmdir(directory) rescue nil
       end
     end
-    Cache.clear
+    cache.clear
   end
 
-  # Return whether the given path is an absolute filesystem path or not
+  # Return whether the given path is an absolute filesystem path.
-  # @param path [String] the path to examine
+  #
+  # @param path [String] the path to examine.
+  #
+  # @return [Boolean] Whether the given path is an absolute filesystem path.
   def self.absolute_path?(path)
     path =~ %r{^(/|\w:[\\/])}
   end
 
   # Return a new path by changing the suffix in path to suffix.
-  # @param path [String] the path to alter
+  #
-  # @param suffix [String] the new filename suffix
+  # @param path [String] The path to alter.
+  # @param suffix [String] The new filename suffix, e.g. ".exe".
+  #
+  # @return [String] New path.
   def self.set_suffix(path, suffix)
     path.sub(/\.[^.]*$/, suffix)
   end
+
+  # Return the system shell and arguments for executing a shell command.
+  #
+  # @return [Array<String>] The shell and flag.
+  def self.get_system_shell
+    @@shell ||=
+      begin
+        test_shell = lambda do |*args|
+          begin
+            "success" == IO.popen([*args, "echo success"]) do |io|
+              io.read.strip
             end
+          rescue
+            false
+          end
+        end
+        if ENV["SHELL"] and ENV["SHELL"] != "" and test_shell[ENV["SHELL"], "-c"]
+          [ENV["SHELL"], "-c"]
+        elsif Object.const_get("RUBY_PLATFORM") =~ /mingw/
+          if test_shell["sh", "-c"]
+            # Using Rscons from MSYS should use MSYS's shell.
+            ["sh", "-c"]
+          else
+            ["cmd", "/c"]
+          end
+        else
+          ["sh", "-c"]
+        end
+      end
+  end
+
+  # Return an Array containing a command used to execute commands.
+  #
+  # This will normally be an empty Array, but on Windows if Rscons detects
+  # that it is running in MSYS then ["env"] will be returned.
+  #
+  # @return [Array<String>] Command used to execute commands.
+  def self.command_executer
+    @@command_executer ||=
+      if Object.const_get("RUBY_PLATFORM") =~ /mingw/
+        if ENV.keys.find {|key| key =~ /MSYS/}
+          begin
+            if IO.popen(["env", "echo", "success"]) {|io| io.read.strip} == "success"
+              ["env"]
+            end
+          rescue
+          end
+        end
+      end || []
+  end
+
+  # Set the command executer array.
+  #
+  # @param val [Array<String>] Command used to execute commands.
+  def self.command_executer=(val)
+    @@command_executer = val
+  end
+end
+
+# Unbuffer $stdout
+$stdout.sync = true

lib/rscons/build_target.rb

@@ -0,0 +1,36 @@
+module Rscons
+  # The BuildTarget class represents a single build target.
+  class BuildTarget
+    # Create a BuildTarget object.
+    #
+    # @param options [Hash] Options to create the BuildTarget with.
+    # @option options [Environment] :env
+    #   The Environment.
+    # @option options [String] :target
+    #   The user-supplied target name.
+    # @option options [Array<String>] :sources
+    #   The user-supplied source file name(s).
+    def initialize(options)
+      @env = options[:env]
+      @target = options[:target]
+    end
+
+    # Manually record a given target as depending on the specified files.
+    #
+    # @param user_deps [Array<String>] Dependency files.
+    #
+    # @return [void]
+    def depends(*user_deps)
+      @env.depends(@target, *user_deps)
+    end
+
+    # Convert the BuildTarget to a String.
+    #
+    # This method always returns the target file name.
+    #
+    # @return [String] Target file name.
+    def to_s
+      @target
+    end
+  end
+end

lib/rscons/builder.rb

@@ -7,30 +7,68 @@ module Rscons
   # Class to hold an object that knows how to build a certain type of file.
   class Builder
     # Return the name of the builder.
+    #
     # If not overridden this defaults to the last component of the class name.
     def name
       self.class.name.split(":").last
     end
 
-    # Return a set of default variable values for the Environment to use
+    # Return a set of default construction variables for the builder.
-    # unless the user overrides any.
+    #
     # @param env [Environment] The Environment.
+    #
+    # @return [Hash] Default construction variables.
     def default_variables(env)
       {}
     end
 
+    # Create a BuildTarget object for this build target.
+    #
+    # Builder sub-classes can override this method to manipulate parameters
+    # (for example, add a suffix to the user-given target file name).
+    #
+    # @param options [Hash] Options to create the BuildTarget with.
+    # @option options [Environment] :env
+    #   The Environment.
+    # @option options [String] :target
+    #   The user-supplied target name.
+    # @option options [Array<String>] :sources
+    #   The user-supplied source file name(s).
+    #
+    # @return [BuildTarget]
+    def create_build_target(options)
+      BuildTarget.new(options)
+    end
+
     # Return whether this builder object is capable of producing a given target
     # file name from a given source file name.
+    #
     # @param target [String] The target file name.
     # @param source [String, Array] The source file name(s).
     # @param env [Environment] The Environment.
+    #
+    # @return [Boolean]
+    #   Whether this builder object is capable of producing a given target
+    #   file name from a given source file name.
     def produces?(target, source, env)
       false
     end
 
     # Check if the cache is up to date for the target and if not execute the
     # build command.
-    # Return the name of the target or false on failure.
+    #
+    # @param short_cmd_string [String]
+    #   Short description of build action to be printed when env.echo ==
+    #   :short.
+    # @param target [String] Name of the target file.
+    # @param command [Array<String>]
+    #   The command to execute to build the target.
+    # @param sources [Array<String>] Source file name(s).
+    # @param env [Environment] The Environment executing the builder.
+    # @param cache [Cache] The Cache object.
+    #
+    # @return [String,false]
+    #   The name of the target on success or false on failure.
     def standard_build(short_cmd_string, target, command, sources, env, cache)
       unless cache.up_to_date?(target, command, sources, env)
         cache.mkdir_p(File.dirname(target))

lib/rscons/builders/cfile.rb

@@ -0,0 +1,55 @@
+module Rscons
+  module Builders
+    # Build a C or C++ source file given a lex (.l, .ll) or yacc (.y, .yy)
+    # input file.
+    #
+    # Examples::
+    #   env.CFile("parser.tab.cc", "parser.yy")
+    #   env.CFile("lex.yy.cc", "parser.ll")
+    class CFile < Builder
+      # Return default construction variables for the builder.
+      #
+      # @param env [Environment] The Environment using the builder.
+      #
+      # @return [Hash] Default construction variables for the builder.
+      def default_variables(env)
+        {
+          "YACC" => "bison",
+          "YACC_FLAGS" => ["-d"],
+          "YACC_CMD" => ["${YACC}", "${YACC_FLAGS}", "-o", "${_TARGET}", "${_SOURCES}"],
+          "LEX" => "flex",
+          "LEX_FLAGS" => [],
+          "LEX_CMD" => ["${LEX}", "${LEX_FLAGS}", "-o", "${_TARGET}", "${_SOURCES}"],
+        }
+      end
+
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
+      def run(target, sources, cache, env, vars)
+        vars = vars.merge({
+          "_TARGET" => target,
+          "_SOURCES" => sources,
+        })
+        cmd =
+          case
+          when sources.first.end_with?(".l", ".ll")
+            "LEX"
+          when sources.first.end_with?(".y", ".yy")
+            "YACC"
+          else
+            raise "Unknown source file #{sources.first.inspect} for CFile builder"
+          end
+        command = env.build_command("${#{cmd}_CMD}", vars)
+        standard_build("#{cmd} #{target}", target, command, sources, env, cache)
+      end
+    end
+  end
+end

lib/rscons/builders/disassemble.rb

@@ -0,0 +1,40 @@
+module Rscons
+  module Builders
+    # The Disassemble builder produces a disassembly listing of a source file.
+    class Disassemble < Builder
+      # Return default construction variables for the builder.
+      #
+      # @param env [Environment] The Environment using the builder.
+      #
+      # @return [Hash] Default construction variables for the builder.
+      def default_variables(env)
+        {
+          "OBJDUMP" => "objdump",
+          "DISASM_CMD" => ["${OBJDUMP}", "${DISASM_FLAGS}", "${_SOURCES}"],
+          "DISASM_FLAGS" => ["--disassemble", "--source"],
+        }
+      end
+
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
+      def run(target, sources, cache, env, vars)
+        vars = vars.merge("_SOURCES" => sources)
+        command = env.build_command("${DISASM_CMD}", vars)
+        unless cache.up_to_date?(target, command, sources, env)
+          cache.mkdir_p(File.dirname(target))
+          return false unless env.execute("Disassemble #{target}", command, options: {out: target})
+          cache.register_build(target, command, sources, env)
+        end
+        target
+      end
+    end
+  end
+end

lib/rscons/builders/library.rb

@@ -1,25 +1,40 @@
 module Rscons
   module Builders
-    # A default RScons builder that produces a static library archive.
+    # A default Rscons builder that produces a static library archive.
-    class Rscons::Builders::Library < Rscons::Builder
+    class Library < Builder
+      # Return default construction variables for the builder.
+      #
+      # @param env [Environment] The Environment using the builder.
+      #
+      # @return [Hash] Default construction variables for the builder.
       def default_variables(env)
         {
           'AR' => 'ar',
           'LIBSUFFIX' => '.a',
-          'ARFLAGS' => [],
+          'ARFLAGS' => ['rcs'],
-          'ARCMD' => ['${AR}', 'rcs', '${ARFLAGS}', '${_TARGET}', '${_SOURCES}']
+          'ARCMD' => ['${AR}', '${ARFLAGS}', '${_TARGET}', '${_SOURCES}']
         }
       end
 
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
       def run(target, sources, cache, env, vars)
         # build sources to linkable objects
-        objects = env.build_sources(sources, [env['OBJSUFFIX'], env['LIBSUFFIX']].flatten, cache, vars)
+        objects = env.build_sources(sources, env.expand_varref(["${OBJSUFFIX}", "${LIBSUFFIX}"], vars).flatten, cache, vars)
         if objects
           vars = vars.merge({
             '_TARGET' => target,
             '_SOURCES' => objects,
           })
-          command = env.build_command(env['ARCMD'], vars)
+          command = env.build_command("${ARCMD}", vars)
           standard_build("AR #{target}", target, command, objects, env, cache)
         end
       end

lib/rscons/builders/object.rb

@@ -1,8 +1,9 @@
 module Rscons
   module Builders
-    # A default RScons builder which knows how to produce an object file from
+    # A default Rscons builder which knows how to produce an object file from
     # various types of source files.
     class Object < Builder
+      # Mapping of known sources from which to build object files.
       KNOWN_SUFFIXES = {
         "AS" => "ASSUFFIX",
         "CC" => "CSUFFIX",
@@ -10,47 +11,78 @@ module Rscons
         "DC" => "DSUFFIX",
       }
 
+      # Return default construction variables for the builder.
+      #
+      # @param env [Environment] The Environment using the builder.
+      #
+      # @return [Hash] Default construction variables for the builder.
       def default_variables(env)
         {
           'OBJSUFFIX' => '.o',
 
+          'CPPDEFPREFIX' => '-D',
+          'INCPREFIX' => '-I',
+
           'AS' => '${CC}',
           'ASFLAGS' => [],
           'ASSUFFIX' => '.S',
           'ASPPPATH' => '${CPPPATH}',
           'ASPPFLAGS' => '${CPPFLAGS}',
           'ASDEPGEN' => ['-MMD', '-MF', '${_DEPFILE}'],
-          'ASCMD' => ['${AS}', '-c', '-o', '${_TARGET}', '${ASDEPGEN}', '-I${ASPPPATH}', '${ASPPFLAGS}', '${ASFLAGS}', '${_SOURCES}'],
+          'ASCMD' => ['${AS}', '-c', '-o', '${_TARGET}', '${ASDEPGEN}', '${INCPREFIX}${ASPPPATH}', '${ASPPFLAGS}', '${ASFLAGS}', '${_SOURCES}'],
 
-          'CPPFLAGS' => [],
+          'CPPFLAGS' => ['${CPPDEFPREFIX}${CPPDEFINES}'],
+          'CPPDEFINES' => [],
           'CPPPATH' => [],
 
+          'CCFLAGS' => [],
+
           'CC' => 'gcc',
           'CFLAGS' => [],
           'CSUFFIX' => '.c',
           'CCDEPGEN' => ['-MMD', '-MF', '${_DEPFILE}'],
-          'CCCMD' => ['${CC}', '-c', '-o', '${_TARGET}', '${CCDEPGEN}', '-I${CPPPATH}', '${CPPFLAGS}', '${CFLAGS}', '${_SOURCES}'],
+          'CCCMD' => ['${CC}', '-c', '-o', '${_TARGET}', '${CCDEPGEN}', '${INCPREFIX}${CPPPATH}', '${CPPFLAGS}', '${CFLAGS}', '${CCFLAGS}', '${_SOURCES}'],
 
           'CXX' => 'g++',
           'CXXFLAGS' => [],
           'CXXSUFFIX' => '.cc',
           'CXXDEPGEN' => ['-MMD', '-MF', '${_DEPFILE}'],
-          'CXXCMD' =>['${CXX}', '-c', '-o', '${_TARGET}', '${CXXDEPGEN}', '-I${CPPPATH}', '${CPPFLAGS}', '${CXXFLAGS}', '${_SOURCES}'],
+          'CXXCMD' =>['${CXX}', '-c', '-o', '${_TARGET}', '${CXXDEPGEN}', '${INCPREFIX}${CPPPATH}', '${CPPFLAGS}', '${CXXFLAGS}', '${CCFLAGS}', '${_SOURCES}'],
 
           'DC' => 'gdc',
           'DFLAGS' => [],
           'DSUFFIX' => '.d',
           'D_IMPORT_PATH' => [],
-          'DCCMD' => ['${DC}', '-c', '-o', '${_TARGET}', '-I${D_IMPORT_PATH}', '${DFLAGS}', '${_SOURCES}'],
+          'DCCMD' => ['${DC}', '-c', '-o', '${_TARGET}', '${INCPREFIX}${D_IMPORT_PATH}', '${DFLAGS}', '${_SOURCES}'],
         }
       end
 
+      # Return whether this builder object is capable of producing a given target
+      # file name from a given source file name.
+      #
+      # @param target [String] The target file name.
+      # @param source [String, Array] The source file name(s).
+      # @param env [Environment] The Environment.
+      #
+      # @return [Boolean]
+      #   Whether this builder object is capable of producing a given target
+      #   file name from a given source file name.
       def produces?(target, source, env)
         target.end_with?(*env['OBJSUFFIX']) and KNOWN_SUFFIXES.find do |compiler, suffix_var|
           source.end_with?(*env[suffix_var])
         end
       end
 
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
       def run(target, sources, cache, env, vars)
         vars = vars.merge({
           '_TARGET' => target,
@@ -58,11 +90,11 @@ module Rscons
           '_DEPFILE' => Rscons.set_suffix(target, '.mf'),
         })
         com_prefix = KNOWN_SUFFIXES.find do |compiler, suffix_var|
-          sources.first.end_with?(*env[suffix_var])
+          sources.first.end_with?(*env.expand_varref("${#{suffix_var}}"))
         end.tap do |v|
           v.nil? and raise "Error: unknown input file type: #{sources.first.inspect}"
         end.first
-        command = env.build_command(env["#{com_prefix}CMD"], vars)
+        command = env.build_command("${#{com_prefix}CMD}", vars)
         unless cache.up_to_date?(target, command, sources, env)
           cache.mkdir_p(File.dirname(target))
           FileUtils.rm_f(target)

lib/rscons/builders/preprocess.rb

@@ -0,0 +1,40 @@
+module Rscons
+  module Builders
+    # The Preprocess builder invokes the C preprocessor
+    class Preprocess < Builder
+      # Return default construction variables for the builder.
+      #
+      # @param env [Environment] The Environment using the builder.
+      #
+      # @return [Hash] Default construction variables for the builder.
+      def default_variables(env)
+        {
+          "CPP_CMD" => ["${_PREPROCESS_CC}", "-E", "-o", "${_TARGET}", "-I${CPPPATH}", "${CPPFLAGS}", "${CFLAGS}", "${_SOURCES}"],
+        }
+      end
+
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
+      def run(target, sources, cache, env, vars)
+        pp_cc = if sources.find {|s| s.end_with?(*env.expand_varref("${CXXSUFFIX}", vars))}
+                  "${CXX}"
+                else
+                  "${CC}"
+                end
+        vars = vars.merge("_PREPROCESS_CC" => pp_cc,
+                          "_TARGET" => target,
+                          "_SOURCES" => sources)
+        command = env.build_command("${CPP_CMD}", vars)
+        standard_build("Preprocess #{target}", target, command, sources, env, cache)
+      end
+    end
+  end
+end

lib/rscons/builders/program.rb

@@ -1,39 +1,80 @@
 module Rscons
   module Builders
-    # A default RScons builder that knows how to link object files into an
+    # A default Rscons builder that knows how to link object files into an
     # executable program.
-    class Rscons::Builders::Program < Rscons::Builder
+    class Program < Builder
+      # Return default construction variables for the builder.
+      #
+      # @param env [Environment] The Environment using the builder.
+      #
+      # @return [Hash] Default construction variables for the builder.
       def default_variables(env)
         {
-          'LD' => nil,
           'OBJSUFFIX' => '.o',
+          'PROGSUFFIX' => (Object.const_get("RUBY_PLATFORM") =~ /mingw|cygwin/ ? ".exe" : ""),
+          'LD' => nil,
           'LIBSUFFIX' => '.a',
           'LDFLAGS' => [],
           'LIBPATH' => [],
+          'LIBDIRPREFIX' => '-L',
+          'LIBLINKPREFIX' => '-l',
           'LIBS' => [],
-          'LDCMD' => ['${LD}', '-o', '${_TARGET}', '${LDFLAGS}', '${_SOURCES}', '-L${LIBPATH}', '-l${LIBS}']
+          'LDCMD' => ['${LD}', '-o', '${_TARGET}', '${LDFLAGS}', '${_SOURCES}', '${LIBDIRPREFIX}${LIBPATH}', '${LIBLINKPREFIX}${LIBS}']
         }
       end
 
+      # Create a BuildTarget object for this build target.
+      #
+      # The build target filename is given a ".exe" suffix if Rscons is
+      # executing on a Windows platform and no other suffix is given.
+      #
+      # @param options [Hash] Options to create the BuildTarget with.
+      # @option options [Environment] :env
+      #   The Environment.
+      # @option options [String] :target
+      #   The user-supplied target name.
+      # @option options [Array<String>] :sources
+      #   The user-supplied source file name(s).
+      #
+      # @return [BuildTarget]
+      def create_build_target(options)
+        my_options = options.dup
+        unless my_options[:target] =~ /\./
+          my_options[:target] += options[:env].expand_varref("${PROGSUFFIX}")
+        end
+        super(my_options)
+      end
+
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
       def run(target, sources, cache, env, vars)
         # build sources to linkable objects
-        objects = env.build_sources(sources, [env['OBJSUFFIX'], env['LIBSUFFIX']].flatten, cache, vars)
+        objects = env.build_sources(sources, env.expand_varref(["${OBJSUFFIX}", "${LIBSUFFIX}"], vars).flatten, cache, vars)
         return false unless objects
-        ld = if env["LD"]
+        ld = env.expand_varref("${LD}", vars)
-               env["LD"]
+        ld = if ld != ""
-             elsif sources.find {|s| s.end_with?(*env["DSUFFIX"])}
+               ld
-               env["DC"]
+             elsif sources.find {|s| s.end_with?(*env.expand_varref("${DSUFFIX}", vars))}
-             elsif sources.find {|s| s.end_with?(*env["CXXSUFFIX"])}
+               "${DC}"
-               env["CXX"]
+             elsif sources.find {|s| s.end_with?(*env.expand_varref("${CXXSUFFIX}", vars))}
+               "${CXX}"
              else
-               env["CC"]
+               "${CC}"
              end
         vars = vars.merge({
           '_TARGET' => target,
           '_SOURCES' => objects,
           'LD' => ld,
         })
-        command = env.build_command(env['LDCMD'], vars)
+        command = env.build_command("${LDCMD}", vars)
         standard_build("LD #{target}", target, command, objects, env, cache)
       end
     end

lib/rscons/cache.rb

@@ -1,100 +1,102 @@
-require 'yaml'
+require "digest/md5"
-require 'fileutils'
+require "fileutils"
-require 'digest/md5'
+require "json"
-require 'set'
+require "set"
-require 'rscons/version'
+require "singleton"
+require "rscons/version"
 
 module Rscons
   # The Cache class keeps track of file checksums, build target commands and
-  # dependencies in a YAML file which persists from one invocation to the next.
+  # dependencies in a JSON file which persists from one invocation to the next.
   # Example cache:
   #   {
-  #     version: '1.2.3',
+  #     "version" => "1.2.3",
-  #     targets: {
+  #     "targets" => {
-  #       'program' => {
+  #       "program" => {
-  #         'checksum' => 'A1B2C3D4',
+  #         "checksum" => "A1B2C3D4",
-  #         'command' => ['gcc', '-o', 'program', 'program.o'],
+  #         "command" => "13543518FE",
-  #         'deps' => [
+  #         "deps" => [
   #           {
-  #             'fname' => 'program.o',
+  #             "fname" => "program.o",
-  #             'checksum' => '87654321',
+  #             "checksum" => "87654321",
   #           },
   #         ],
-  #         'user_deps' => [
+  #         "user_deps" => [
   #           {
-  #             'fname' => 'lscript.ld',
+  #             "fname" => "lscript.ld",
-  #             'checksum' => '77551133',
+  #             "checksum" => "77551133",
   #           },
   #         ],
   #       },
-  #       'program.o' => {
+  #       "program.o" => {
-  #         'checksum' => '87654321',
+  #         "checksum" => "87654321",
-  #         'command' => ['gcc', '-c', '-o', 'program.o', 'program.c'],
+  #         "command" => "98765ABCD",
-  #         'deps' => [
+  #         "deps" => [
   #           {
-  #             'fname' => 'program.c',
+  #             "fname" => "program.c",
-  #             'checksum' => '456789ABC',
+  #             "checksum" => "456789ABC",
   #           },
   #           {
-  #             'fname' => 'program.h',
+  #             "fname" => "program.h",
-  #             'checksum' => '7979764643',
+  #             "checksum" => "7979764643",
   #           },
   #         ],
-  #         'user_deps' => [],
+  #         "user_deps" => [],
   #       }
   #     },
-  #     directories: {
+  #     "directories" => {
-  #       'build' => true,
+  #       "build" => true,
-  #       'build/one' => true,
+  #       "build/one" => true,
-  #       'build/two' => true,
+  #       "build/two" => true,
   #     },
   #   }
   class Cache
-    #### Constants
+    include Singleton
 
     # Name of the file to store cache information in
-    CACHE_FILE = '.rsconscache'
+    CACHE_FILE = ".rsconscache"
-
-    #### Class Methods
-
-    # Remove the cache file
-    def self.clear
-      FileUtils.rm_f(CACHE_FILE)
-    end
-
-    #### Instance Methods
 
     # Create a Cache object and load in the previous contents from the cache
     # file.
     def initialize
-      @cache = YAML.load(File.read(CACHE_FILE)) rescue {}
+      initialize!
-      unless @cache.is_a?(Hash)
-        $stderr.puts "Warning: #{CACHE_FILE} was corrupt. Contents:\n#{@cache.inspect}"
-        @cache = {}
     end
-      @cache[:targets] ||= {}
+
-      @cache[:directories] ||= {}
+    # Remove the cache file.
+    def clear
+      FileUtils.rm_f(CACHE_FILE)
+      initialize!
+    end
+
+    # Clear the cached file checksums.
+    def clear_checksum_cache!
       @lookup_checksums = {}
     end
 
     # Write the cache to disk to be loaded next time.
     def write
-      @cache[:version] = VERSION
+      if @dirty || (@cache["version"] != VERSION)
-      File.open(CACHE_FILE, 'w') do |fh|
+        @cache["version"] = VERSION
-        fh.puts(YAML.dump(@cache))
+        File.open(CACHE_FILE, "w") do |fh|
+          fh.puts(JSON.dump(@cache))
         end
       end
+      @dirty = false
+    end
 
-    # Check if target(s) are up to date
+    # Check if target(s) are up to date.
+    #
     # @param targets [String, Array] The name(s) of the target file(s).
     # @param command [String, Array] The command used to build the target.
     # @param deps [Array] List of the target's dependency files.
     # @param env [Environment] The Rscons::Environment.
-    # @param options [Hash] Optional options. Can contain the following keys:
+    # @param options [Hash] Optional options.
-    #   :strict_deps::
+    # @option options [Boolean] :strict_deps
     #   Only consider a target up to date if its list of dependencies is
     #   exactly equal (including order) to the cached list of dependencies
-    # @return true if the targets are all up to date, meaning that,
+    #
+    # @return [Boolean]
+    #   True value if the targets are all up to date, meaning that,
     #   for each target:
     #   - the target exists on disk
     #   - the cache has information for the target
@@ -111,16 +113,16 @@ module Rscons
         return false unless File.exists?(target)
 
         # target must be registered in the cache
-        return false unless @cache[:targets].has_key?(target)
+        return false unless @cache["targets"].has_key?(target)
 
         # target must have the same checksum as when it was built last
-        return false unless @cache[:targets][target][:checksum] == lookup_checksum(target)
+        return false unless @cache["targets"][target]["checksum"] == lookup_checksum(target)
 
         # command used to build target must be identical
-        return false unless @cache[:targets][target][:command] == command
+        return false unless @cache["targets"][target]["command"] == Digest::MD5.hexdigest(command.inspect)
 
-        cached_deps = @cache[:targets][target][:deps] || []
+        cached_deps = @cache["targets"][target]["deps"] || []
-        cached_deps_fnames = cached_deps.map { |dc| dc[:fname] }
+        cached_deps_fnames = cached_deps.map { |dc| dc["fname"] }
         if options[:strict_deps]
           # depedencies passed in must exactly equal those in the cache
           return false unless deps == cached_deps_fnames
@@ -131,82 +133,116 @@ module Rscons
 
         # set of user dependencies must match
         user_deps = env.get_user_deps(target) || []
-        cached_user_deps = @cache[:targets][target][:user_deps] || []
+        cached_user_deps = @cache["targets"][target]["user_deps"] || []
-        cached_user_deps_fnames = cached_user_deps.map { |dc| dc[:fname] }
+        cached_user_deps_fnames = cached_user_deps.map { |dc| dc["fname"] }
         return false unless user_deps == cached_user_deps_fnames
 
         # all cached dependencies must have their checksums match
         (cached_deps + cached_user_deps).each do |dep_cache|
-          return false unless dep_cache[:checksum] == lookup_checksum(dep_cache[:fname])
+          return false unless dep_cache["checksum"] == lookup_checksum(dep_cache["fname"])
         end
       end
 
       true
     end
 
-    # Store cache information about target(s) built by a builder
+    # Store cache information about target(s) built by a builder.
+    #
     # @param targets [String, Array] The name of the target(s) built.
     # @param command [String, Array] The command used to build the target.
     # @param deps [Array] List of dependencies for the target.
-    # @param env [Environment] The Rscons::Environment.
+    # @param env [Environment] The {Rscons::Environment}.
+    #
+    # @return [void]
     def register_build(targets, command, deps, env)
       Array(targets).each do |target|
-        @cache[:targets][target.encode(__ENCODING__)] = {
+        @cache["targets"][target] = {
-          command: command,
+          "command" => Digest::MD5.hexdigest(command.inspect),
-          checksum: calculate_checksum(target),
+          "checksum" => calculate_checksum(target),
-          deps: deps.map do |dep|
+          "deps" => deps.map do |dep|
             {
-              fname: dep.encode(__ENCODING__),
+              "fname" => dep,
-              checksum: lookup_checksum(dep),
+              "checksum" => lookup_checksum(dep),
             }
           end,
-          user_deps: (env.get_user_deps(target) || []).map do |dep|
+          "user_deps" => (env.get_user_deps(target) || []).map do |dep|
             {
-              fname: dep.encode(__ENCODING__),
+              "fname" => dep,
-              checksum: lookup_checksum(dep),
+              "checksum" => lookup_checksum(dep),
             }
           end,
         }
+        @dirty = true
       end
     end
 
-    # Return a list of targets that have been built
+    # Return a list of targets that have been built.
+    #
+    # @return [Array<String>] List of targets that have been built.
     def targets
-      @cache[:targets].keys
+      @cache["targets"].keys
     end
 
     # Make any needed directories and record the ones that are created for
     # removal upon a "clean" operation.
+    #
+    # @param path [String] Directory to create.
+    #
+    # @return [void]
     def mkdir_p(path)
       parts = path.split(/[\\\/]/)
-      (0..parts.size-1).each do |i|
+      parts.each_index do |i|
-        subpath = File.join(*parts[0, i + 1]).encode(__ENCODING__)
+        next if parts[i] == ""
+        subpath = File.join(*parts[0, i + 1])
         unless File.exists?(subpath)
           FileUtils.mkdir(subpath)
-          @cache[:directories][subpath] = true
+          @cache["directories"][subpath] = true
+          @dirty = true
         end
       end
     end
 
-    # Return a list of directories which were created as a part of the build
+    # Return a list of directories which were created as a part of the build.
+    #
+    # @return [Array<String>]
+    #   List of directories which were created as a part of the build.
     def directories
-      @cache[:directories].keys
+      @cache["directories"].keys
     end
 
-    # Private Instance Methods
     private
 
+    # Create a Cache object and load in the previous contents from the cache
+    # file.
+    def initialize!
+      @cache = JSON.load(File.read(CACHE_FILE)) rescue {}
+      unless @cache.is_a?(Hash)
+        $stderr.puts "Warning: #{CACHE_FILE} was corrupt. Contents:\n#{@cache.inspect}"
+        @cache = {}
+      end
+      @cache["targets"] ||= {}
+      @cache["directories"] ||= {}
+      @lookup_checksums = {}
+      @dirty = false
+    end
+
     # Return a file's checksum, or the previously calculated checksum for
-    # the same file
+    # the same file.
+    #
     # @param file [String] The file name.
+    #
+    # @return [String] The file's checksum.
     def lookup_checksum(file)
       @lookup_checksums[file] || calculate_checksum(file)
     end
 
-    # Calculate and return a file's checksum
+    # Calculate and return a file's checksum.
+    #
     # @param file [String] The file name.
+    #
+    # @return [String] The file's checksum.
     def calculate_checksum(file)
-      @lookup_checksums[file] = Digest::MD5.hexdigest(File.read(file, mode: 'rb')).encode(__ENCODING__) rescue ''
+      @lookup_checksums[file] = Digest::MD5.hexdigest(File.read(file, mode: "rb")) rescue ""
     end
   end
 end

lib/rscons/environment.rb

@@ -1,29 +1,39 @@
-require 'set'
+require "fileutils"
-require 'fileutils'
+require "set"
+require "shellwords"
 
 module Rscons
-  # The Environment class is the main programmatic interface to RScons. It
+  # The Environment class is the main programmatic interface to Rscons. It
   # contains a collection of construction variables, options, builders, and
   # rules for building targets.
   class Environment
-    # Hash of +{"builder_name" => builder_object}+ pairs.
+    # @return [Hash] Set of \{"builder_name" => builder_object} pairs.
     attr_reader :builders
 
     # :command, :short, or :off
     attr_accessor :echo
 
-    # String or +nil+
+    # @return [String, nil] The build root.
     attr_reader :build_root
+
+    # Set the build root.
+    #
+    # @param build_root [String] The build root.
     def build_root=(build_root)
-      @build_root = build_root.gsub('\\', '/')
+      @build_root = build_root
+      @build_root.gsub!('\\', '/') if @build_root
     end
 
     # Create an Environment object.
+    #
     # @param options [Hash]
-    # Possible options keys:
+    # @option options [Symbol] :echo
-    #   :echo => :command, :short, or :off (default :short)
+    #   :command, :short, or :off (default :short)
-    #   :build_root => String specifying build root directory (default nil)
+    # @option options [String] :build_root
-    #   :exclude_builders => true to omit adding default builders (default false)
+    #   Build root directory (default nil)
+    # @option options [Boolean] :exclude_builders
+    #   Whether to omit adding default builders (default false)
+    #
     # If a block is given, the Environment object is yielded to the block and
     # when the block returns, the {#process} method is automatically called.
     def initialize(options = {})
@@ -50,24 +60,53 @@ module Rscons
     end
 
     # Make a copy of the Environment object.
-    # The cloned environment will contain a copy of all environment options,
+    #
-    # construction variables, and builders (unless :exclude_builders => true is
+    # By default, a cloned environment will contain a copy of all environment
-    # passed as an option). It will not contain a copy of the targets, build
+    # options, construction variables, and builders, but not a copy of the
-    # hooks, build directories, or the build root.  If a block is given, the
+    # targets, build hooks, build directories, or the build root.
-    # Environment object is yielded to the block and when the block returns,
+    #
-    # the {#process} method is automatically called.  The possible options keys
+    # Exactly which items are cloned are controllable via the optional :clone
-    # match those documented in the #initialize method.
+    # parameter, which can be :none, :all, or a set or array of any of the
+    # following:
+    # - :variables to clone construction variables (on by default)
+    # - :builders to clone the builders (on by default)
+    # - :build_root to clone the build root (off by default)
+    # - :build_dirs to clone the build directories (off by default)
+    # - :build_hooks to clone the build hooks (off by default)
+    #
+    # If a block is given, the Environment object is yielded to the block and
+    # when the block returns, the {#process} method is automatically called.
+    #
+    # Any options that #initialize receives can also be specified here.
+    #
+    # @return a new {Environment} object.
     def clone(options = {})
+      clone = options[:clone] || Set[:variables, :builders]
+      clone = Set[:variables, :builders, :build_root, :build_dirs, :build_hooks] if clone == :all
+      clone = Set[] if clone == :none
+      clone = Set.new(clone) if clone.is_a?(Array)
+      clone.delete(:builders) if options[:exclude_builders]
       env = self.class.new(
         echo: options[:echo] || @echo,
         build_root: options[:build_root],
         exclude_builders: true)
-      unless options[:exclude_builders]
+      if clone.include?(:builders)
         @builders.each do |builder_name, builder|
           env.add_builder(builder)
         end
       end
-      env.append(@varset.clone)
+      env.append(@varset) if clone.include?(:variables)
+      env.build_root = @build_root if clone.include?(:build_root)
+      if clone.include?(:build_dirs)
+        @build_dirs.each do |src_dir, obj_dir|
+          env.build_dir(src_dir, obj_dir)
+        end
+      end
+      if clone.include?(:build_hooks)
+        @build_hooks.each do |build_hook_block|
+          env.add_build_hook(&build_hook_block)
+        end
+      end
 
       if block_given?
         yield env
@@ -77,6 +116,10 @@ module Rscons
     end
 
     # Add a {Builder} object to the Environment.
+    #
+    # @param builder [Builder] The {Builder} object to add.
+    #
+    # @return [void]
     def add_builder(builder)
       @builders[builder.name] = builder
       var_defs = builder.default_variables(self)
@@ -88,19 +131,45 @@ module Rscons
     end
 
     # Add a build hook to the Environment.
+    #
+    # @yield [build_op]
+    #   Invoke the given block with the current build operation.
+    # @yieldparam build_op [Hash]
+    #   Hash with keys:
+    #   - :builder - The builder object in use.
+    #   - :target - Target file name.
+    #   - :sources - List of source file(s).
+    #   - :vars - Set of construction variable values in use.
+    #   - :env - The Environment invoking the builder.
+    #
+    # @return [void]
     def add_build_hook(&block)
       @build_hooks << block
     end
 
     # Specify a build directory for this Environment.
+    #
     # Source files from src_dir will produce object files under obj_dir.
+    #
+    # @param src_dir [String] Path to the source directory.
+    # @param obj_dir [String] Path to the object directory.
+    #
+    # @return [void]
     def build_dir(src_dir, obj_dir)
       src_dir = src_dir.gsub('\\', '/') if src_dir.is_a?(String)
       @build_dirs << [src_dir, obj_dir]
     end
 
-    # Return the file name to be built from source_fname with suffix suffix.
+    # Return the file name to be built from +source_fname+ with suffix
+    # +suffix+.
+    #
     # This method takes into account the Environment's build directories.
+    #
+    # @param source_fname [String] Source file name.
+    # @param suffix [String] Suffix, including "." if desired.
+    #
+    # @return [String]
+    #   The file name to be built from +source_fname+ with suffix +suffix+.
     def get_build_fname(source_fname, suffix)
       build_fname = Rscons.set_suffix(source_fname, suffix).gsub('\\', '/')
       found_match = @build_dirs.find do |src_dir, obj_dir|
@@ -120,81 +189,98 @@ module Rscons
     end
 
     # Access a construction variable or environment option.
+    #
     # @see VarSet#[]
     def [](*args)
       @varset.send(:[], *args)
     end
 
     # Set a construction variable or environment option.
+    #
     # @see VarSet#[]=
     def []=(*args)
       @varset.send(:[]=, *args)
     end
 
     # Add a set of construction variables or environment options.
+    #
     # @see VarSet#append
     def append(*args)
-      @varset.send(:append, *args)
+      @varset.append(*args)
     end
 
-    # Build all target specified in the Environment.
+    # Build all build targets specified in the Environment.
+    #
     # When a block is passed to Environment.new, this method is automatically
     # called after the block returns.
+    #
+    # @return [void]
     def process
-      cache = Cache.new
+      unless @targets.empty?
+        expand_paths!
+        cache = Cache.instance
+        cache.clear_checksum_cache!
         targets_processed = {}
         process_target = proc do |target|
           targets_processed[target] ||= begin
-          @targets[target][:source].each do |src|
+            @targets[target][:sources].each do |src|
               if @targets.include?(src) and not targets_processed.include?(src)
                 process_target.call(src)
               end
             end
             result = run_builder(@targets[target][:builder],
                                  target,
-                               @targets[target][:source],
+                                 @targets[target][:sources],
                                  cache,
                                  @targets[target][:vars] || {})
             unless result
-            cache.write
               raise BuildError.new("Failed to build #{target}")
             end
             result
           end
         end
-      @targets.each do |target, info|
+        begin
+          @targets.each do |target, target_params|
             process_target.call(target)
           end
+        ensure
           cache.write
         end
+      end
+    end
 
     # Clear all targets registered for the Environment.
     def clear_targets
       @targets = {}
     end
 
-    # Build a command line from the given template, resolving references to
+    # Expand a construction variable reference.
-    # variables using the Environment's construction variables and any extra
+    #
-    # variables specified.
+    # @param varref [Array, String] Variable reference to expand.
-    # @param command_template [Array] template for the command with variable
+    # @param extra_vars [Hash, VarSet]
-    #   references
+    #   Extra variables to use in addition to (or replace) the Environment's
-    # @param extra_vars [Hash, VarSet] extra variables to use in addition to
+    #   construction variables when expanding the variable reference.
-    #   (or replace) the Environment's construction variables when building
+    #
-    #   the command
+    # @return [Array, String] Expansion of the variable reference.
-    def build_command(command_template, extra_vars)
+    def expand_varref(varref, extra_vars = nil)
-      @varset.merge(extra_vars).expand_varref(command_template)
+      if extra_vars.nil?
+        @varset
+      else
+        @varset.merge(extra_vars)
+      end.expand_varref(varref)
     end
+    alias_method :build_command, :expand_varref
 
-    # Expand a construction variable reference (String or Array)
+    # Execute a builder command.
-    def expand_varref(varref)
+    #
-      @varset.expand_varref(varref)
-    end
-
-    # Execute a builder command
     # @param short_desc [String] Message to print if the Environment's echo
     #   mode is set to :short
     # @param command [Array] The command to execute.
-    # @param options [Hash] Optional options to pass to Kernel#system.
+    # @param options [Hash] Optional options, possible keys:
+    #   - :env - environment Hash to pass to Kernel#system.
+    #   - :options - options Hash to pass to Kernel#system.
+    #
+    # @return [true,false,nil] Return value from Kernel.system().
     def execute(short_desc, command, options = {})
       print_command = proc do
         puts command.map { |c| c =~ /\s/ ? "'#{c}'" : c }.join(' ')
@@ -204,7 +290,9 @@ module Rscons
       elsif @echo == :short
         puts short_desc
       end
-      system(*command, options).tap do |result|
+      env_args = options[:env] ? [options[:env]] : []
+      options_args = options[:options] ? [options[:options]] : []
+      system(*env_args, *Rscons.command_executer, *command, *options_args).tap do |result|
         unless result or @echo == :command
           $stdout.write "Failed command was: "
           print_command.call
@@ -212,46 +300,82 @@ module Rscons
       end
     end
 
-    alias_method :orig_method_missing, :method_missing
+    # Define a build target.
+    #
+    # @param method [Symbol] Method name.
+    # @param args [Array] Method arguments.
+    #
+    # @return [BuildTarget]
+    #   The {BuildTarget} object registered, if the method called is a
+    #   {Builder}.
     def method_missing(method, *args)
       if @builders.has_key?(method.to_s)
-        target, source, vars, *rest = args
+        target, sources, vars, *rest = args
         unless vars.nil? or vars.is_a?(Hash) or vars.is_a?(VarSet)
           raise "Unexpected construction variable set: #{vars.inspect}"
         end
-        source = [source] unless source.is_a?(Array)
+        sources = Array(sources)
-        @targets[target] = {
+        builder = @builders[method.to_s]
-          builder: @builders[method.to_s],
+        build_target = builder.create_build_target(env: self, target: target, sources: sources)
-          source: source,
+        add_target(build_target.to_s, builder, sources, vars, rest)
-          vars: vars,
+        build_target
-          args: rest,
-        }
       else
-        orig_method_missing(method, *args)
+        super
       end
     end
 
-    # Manually record a given target as depending on the specified
+    # Add a build target.
-    # dependency files.
+    #
+    # @param target [String] Build target file name.
+    # @param builder [Builder] The {Builder} to use to build the target.
+    # @param sources [Array<String>] Source file name(s).
+    # @param vars [Hash] Construction variable overrides.
+    # @param args [Object] Any extra arguments passed to the {Builder}.
+    #
+    # @return [void]
+    def add_target(target, builder, sources, vars, args)
+      @targets[target] = {
+        builder: builder,
+        sources: sources,
+        vars: vars,
+        args: args,
+      }
+    end
+
+    # Manually record a given target as depending on the specified files.
+    #
+    # @param target [String,BuildTarget] Target file.
+    # @param user_deps [Array<String>] Dependency files.
+    #
+    # @return [void]
     def depends(target, *user_deps)
+      target = target.to_s
       @user_deps[target] ||= []
       @user_deps[target] = (@user_deps[target] + user_deps).uniq
     end
 
-    # Return the list of user dependencies for a given target, or +nil+ for
+    # Return the list of user dependencies for a given target.
-    # none.
+    #
+    # @param target [String] Target file name.
+    #
+    # @return [Array<String>,nil]
+    #   List of user-specified dependencies for the target, or nil if none were
+    #   specified.
     def get_user_deps(target)
       @user_deps[target]
     end
 
     # Build a list of source files into files containing one of the suffixes
     # given by suffixes.
-    # This method is used internally by RScons builders.
+    #
+    # This method is used internally by Rscons builders.
+    #
     # @param sources [Array] List of source files to build.
     # @param suffixes [Array] List of suffixes to try to convert source files into.
     # @param cache [Cache] The Cache.
     # @param vars [Hash] Extra variables to pass to the builder.
-    # Return a list of the converted file names.
+    #
+    # @return [Array<String>] List of the converted file name(s).
     def build_sources(sources, suffixes, cache, vars)
       sources.map do |source|
         if source.end_with?(*suffixes)
@@ -273,12 +397,14 @@ module Rscons
     end
 
     # Invoke a builder to build the given target based on the given sources.
+    #
     # @param builder [Builder] The Builder to use.
     # @param target [String] The target output file.
     # @param sources [Array] List of source files.
     # @param cache [Cache] The Cache.
     # @param vars [Hash] Extra variables to pass to the builder.
-    # Return the result of the builder's run() method.
+    #
+    # @return [String,false] Return value from the {Builder}'s +run+ method.
     def run_builder(builder, target, sources, cache, vars)
       vars = @varset.merge(vars)
       @build_hooks.each do |build_hook_block|
@@ -287,16 +413,206 @@ module Rscons
           target: target,
           sources: sources,
           vars: vars,
+          env: self,
         }
         build_hook_block.call(build_operation)
       end
       builder.run(target, sources, cache, self, vars)
     end
 
+    # Expand a path to be relative to the Environment's build root.
+    #
+    # Paths beginning with "^/" are expanded by replacing "^" with the
+    # Environment's build root.
+    #
+    # @param path [String] The path to expand.
+    #
+    # @return [String] The expanded path.
+    def expand_path(path)
+      path.sub(%r{^\^(?=[\\/])}, @build_root)
+    end
+
+    # Execute a command using the system shell.
+    #
+    # The shell is automatically determined but can be overridden by the SHELL
+    # construction variable. If the SHELL construction variable is specified,
+    # the flag to pass to the shell is automatically dtermined but can be
+    # overridden by the SHELLFLAG construction variable.
+    #
+    # @param command [String] Command to execute.
+    #
+    # @return [String] The command's standard output.
+    def shell(command)
+      shell_cmd =
+        if self["SHELL"]
+          flag = self["SHELLFLAG"] || (self["SHELL"] == "cmd" ? "/c" : "-c")
+          [self["SHELL"], flag]
+        else
+          Rscons.get_system_shell
+        end
+      IO.popen([*shell_cmd, command]) do |io|
+        io.read
+      end
+    end
+
+    # @!method parse_flags(flags)
+    # @!method parse_flags!(flags)
+    #
+    # Parse command-line flags for compilation/linking options into separate
+    # construction variables.
+    #
+    # The parsed construction variables are returned in a Hash instead of
+    # merging them directly to the Environment. They can be merged with
+    # {#merge_flags}. The {#parse_flags!} version immediately merges the parsed
+    # flags as well.
+    #
+    # Example:
+    #   # Import FreeType build options
+    #   env.parse_flags!("!freetype-config --cflags --libs")
+    #
+    # @param flags [String]
+    #   String containing the flags to parse, or if the flags string begins
+    #   with "!", a shell command to execute using {#shell} to obtain the
+    #   flags to parse.
+    #
+    # @return [Hash] Set of construction variables to append.
+    def parse_flags(flags)
+      if flags =~ /^!(.*)$/
+        flags = shell($1)
+      end
+      rv = {}
+      words = Shellwords.split(flags)
+      skip = false
+      words.each_with_index do |word, i|
+        if skip
+          skip = false
+          next
+        end
+        append = lambda do |var, val|
+          rv[var] ||= []
+          rv[var] += val
+        end
+        handle = lambda do |var, val|
+          if val.nil? or val.empty?
+            val = words[i + 1]
+            skip = true
+          end
+          if val and not val.empty?
+            append[var, [val]]
+          end
+        end
+        if word == "-arch"
+          if val = words[i + 1]
+            append["CCFLAGS", ["-arch", val]]
+            append["LDFLAGS", ["-arch", val]]
+          end
+          skip = true
+        elsif word =~ /^#{self["CPPDEFPREFIX"]}(.*)$/
+          handle["CPPDEFINES", $1]
+        elsif word == "-include"
+          if val = words[i + 1]
+            append["CCFLAGS", ["-include", val]]
+          end
+          skip = true
+        elsif word == "-isysroot"
+          if val = words[i + 1]
+            append["CCFLAGS", ["-isysroot", val]]
+            append["LDFLAGS", ["-isysroot", val]]
+          end
+          skip = true
+        elsif word =~ /^#{self["INCPREFIX"]}(.*)$/
+          handle["CPPPATH", $1]
+        elsif word =~ /^#{self["LIBLINKPREFIX"]}(.*)$/
+          handle["LIBS", $1]
+        elsif word =~ /^#{self["LIBDIRPREFIX"]}(.*)$/
+          handle["LIBPATH", $1]
+        elsif word == "-mno-cygwin"
+          append["CCFLAGS", [word]]
+          append["LDFLAGS", [word]]
+        elsif word == "-mwindows"
+          append["LDFLAGS", [word]]
+        elsif word == "-pthread"
+          append["CCFLAGS", [word]]
+          append["LDFLAGS", [word]]
+        elsif word =~ /^-std=/
+          append["CFLAGS", [word]]
+        elsif word =~ /^-Wa,(.*)$/
+          append["ASFLAGS", $1.split(",")]
+        elsif word =~ /^-Wl,(.*)$/
+          append["LDFLAGS", $1.split(",")]
+        elsif word =~ /^-Wp,(.*)$/
+          append["CPPFLAGS", $1.split(",")]
+        elsif word.start_with?("-")
+          append["CCFLAGS", [word]]
+        elsif word.start_with?("+")
+          append["CCFLAGS", [word]]
+          append["LDFLAGS", [word]]
+        else
+          append["LIBS", [word]]
+        end
+      end
+      rv
+    end
+
+    def parse_flags!(flags)
+      flags = parse_flags(flags)
+      merge_flags(flags)
+      flags
+    end
+
+    # Merge construction variable flags into this Environment's construction
+    # variables.
+    #
+    # This method does the same thing as {#append}, except that Array values in
+    # +flags+ are appended to the end of Array construction variables instead
+    # of replacing their contents.
+    #
+    # @param flags [Hash]
+    #   Set of construction variables to merge into the current Environment.
+    #   This can be the value (or a modified version) returned by
+    #   {#parse_flags}.
+    #
+    # @return [void]
+    def merge_flags(flags)
+      flags.each_pair do |key, val|
+        if self[key].is_a?(Array) and val.is_a?(Array)
+          self[key] += val
+        else
+          self[key] = val
+        end
+      end
+    end
+
+    private
+
+    # Expand target and source paths before invoking builders.
+    #
+    # This method expand construction variable references in the target and
+    # source file names before passing them to the builder. It also expands
+    # "^/" prefixes to the Environment's build root if a build root is defined.
+    #
+    # @return [void]
+    def expand_paths!
+      @targets = @targets.reduce({}) do |result, (target, target_params)|
+        sources = target_params[:sources].map do |source|
+          source = expand_path(source) if @build_root
+          expand_varref(source)
+        end
+        target = expand_path(target) if @build_root
+        target = expand_varref(target)
+        result[target] = target_params.merge(sources: sources)
+        result
+      end
+    end
+
     # Parse dependencies for a given target from a Makefile.
-    # This method is used internally by RScons builders.
+    #
+    # This method is used internally by Rscons builders.
+    #
     # @param mf_fname [String] File name of the Makefile to read.
     # @param target [String] Name of the target to gather dependencies for.
+    #
+    # @return [Array<String>] Paths of dependency files.
     def self.parse_makefile_deps(mf_fname, target)
       deps = []
       buildup = ''

lib/rscons/varset.rb

@@ -1,51 +1,95 @@
 module Rscons
-  # This class represents a collection of variables which can be accessed
+  # This class represents a collection of variables which supports efficient
-  # as certain types
+  # deep cloning.
   class VarSet
-    # The underlying hash
+    # Create a VarSet.
-    attr_reader :vars
+    #
-
-    # Create a VarSet
     # @param vars [Hash] Optional initial variables.
     def initialize(vars = {})
-      if vars.is_a?(VarSet)
+      @my_vars = {}
-        @vars = vars.clone.vars
+      @coa_vars = []
-      else
+      append(vars)
-        @vars = vars
-      end
     end
 
-    # Access the value of variable as a particular type
+    # Access the value of variable.
+    #
     # @param key [String, Symbol] The variable name.
+    #
+    # @return [Object] The variable's value.
     def [](key)
-      @vars[key]
+      if @my_vars.include?(key)
+        @my_vars[key]
+      else
+        @coa_vars.each do |coa_vars|
+          if coa_vars.include?(key)
+            @my_vars[key] = deep_dup(coa_vars[key])
+            return @my_vars[key]
+          end
+        end
+        nil
+      end
     end
 
     # Assign a value to a variable.
+    #
     # @param key [String, Symbol] The variable name.
-    # @param val [Object] The value.
+    #
+    # @param val [Object] The value to set.
     def []=(key, val)
-      @vars[key] = val
+      @my_vars[key] = val
     end
 
-    # Add or overwrite a set of variables
+    # Check if the VarSet contains a variable.
+    #
+    # @param key [String, Symbol] The variable name.
+    #
+    # @return [Boolean] Whether the VarSet contains the variable.
+    def include?(key)
+      if @my_vars.include?(key)
+        true
+      else
+        @coa_vars.find do |coa_vars|
+          coa_vars.include?(key)
+        end
+      end
+    end
+
+    # Add or overwrite a set of variables.
+    #
     # @param values [VarSet, Hash] New set of variables.
+    #
+    # @return [self]
     def append(values)
-      values = values.vars if values.is_a?(VarSet)
+      coa!
-      @vars.merge!(Marshal.load(Marshal.dump(values)))
+      if values.is_a?(VarSet)
+        values.send(:coa!)
+        @coa_vars = values.instance_variable_get(:@coa_vars) + @coa_vars
+      else
+        @my_vars = deep_dup(values)
+      end
       self
     end
 
     # Create a new VarSet object based on the first merged with other.
+    #
     # @param other [VarSet, Hash] Other variables to add or overwrite.
+    #
+    # @return [VarSet] The newly created VarSet.
     def merge(other = {})
-      VarSet.new(Marshal.load(Marshal.dump(@vars))).append(other)
+      coa!
+      varset = self.class.new
+      varset.instance_variable_set(:@coa_vars, @coa_vars.dup)
+      varset.append(other)
     end
     alias_method :clone, :merge
 
-    # Replace "$" variable references in varref with the variables values,
+    # Replace "$\{var}" variable references in varref with the expanded
-    # recursively.
+    # variables' values, recursively.
+    #
     # @param varref [String, Array] Value containing references to variables.
+    #
+    # @return [String, Array]
+    #   Expanded value with "$\{var}" variable references replaced.
     def expand_varref(varref)
       if varref.is_a?(Array)
         varref.map do |ent|
@@ -54,18 +98,54 @@ module Rscons
       else
         if varref =~ /^(.*)\$\{([^}]+)\}(.*)$/
           prefix, varname, suffix = $1, $2, $3
-          varval = expand_varref(@vars[varname])
+          varval = expand_varref(self[varname])
-          if varval.is_a?(String)
+          if varval.is_a?(String) or varval.nil?
             expand_varref("#{prefix}#{varval}#{suffix}")
           elsif varval.is_a?(Array)
             varval.map {|vv| expand_varref("#{prefix}#{vv}#{suffix}")}.flatten
           else
-            raise "I do not know how to expand a variable reference to a #{varval.class.name} (from #{varname.inspect} => #{@vars[varname].inspect})"
+            raise "I do not know how to expand a variable reference to a #{varval.class.name} (from #{varname.inspect} => #{self[varname].inspect})"
           end
         else
           varref
         end
       end
     end
+
+    private
+
+    # Move all VarSet variables into the copy-on-access list.
+    #
+    # @return [void]
+    def coa!
+      unless @my_vars.empty?
+        @coa_vars.unshift(@my_vars)
+        @my_vars = {}
+      end
+    end
+
+    # Create a deep copy of an object.
+    #
+    # Only objects which are of type String, Array, or Hash are deep copied.
+    # Any other object just has its referenced copied.
+    #
+    # @param obj [Object] Object to deep copy.
+    #
+    # @return [Object] Deep copied value.
+    def deep_dup(obj)
+      obj_class = obj.class
+      if obj_class == Hash
+        obj.reduce({}) do |result, (k, v)|
+          result[k] = deep_dup(v)
+          result
+        end
+      elsif obj_class == Array
+        obj.map { |v| deep_dup(v) }
+      elsif obj_class == String
+        obj.dup
+      else
+        obj
+      end
+    end
   end
 end

lib/rscons/version.rb

@@ -1,4 +1,4 @@
 module Rscons
   # gem version
-  VERSION = "1.1.0"
+  VERSION = "1.5.0"
 end

rscons.gemspec

@@ -1,30 +1,28 @@
 # -*- encoding: utf-8 -*-
-lib = File.expand_path('../lib', __FILE__)
+lib = File.expand_path("../lib", __FILE__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
-require 'rscons/version'
+require "rscons/version"
 
 Gem::Specification.new do |gem|
   gem.name          = "rscons"
   gem.version       = Rscons::VERSION
   gem.authors       = ["Josh Holtrop"]
   gem.email         = ["jholtrop@gmail.com"]
-  gem.description   = %q{Software construction library inspired by SCons and implemented in Ruby}
+  gem.description   = %q{Software construction library inspired by SCons and implemented in Ruby.}
   gem.summary       = %q{Software construction library inspired by SCons and implemented in Ruby}
   gem.homepage      = "https://github.com/holtrop/rscons"
-  gem.license       = 'MIT'
+  gem.license       = "MIT"
 
-  gem.files         = `git ls-files`.split($/)
+  gem.files         = Dir["{bin,assets,lib}/**/*", "*.gemspec", "LICENSE.txt"]
   gem.executables   = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
 
-  gem.add_development_dependency "rspec-core"
+  gem.add_dependency "json", "~> 1.0"
-  gem.add_development_dependency "rspec-mocks"
+
-  gem.add_development_dependency "rspec-expectations"
   gem.add_development_dependency "rspec"
   gem.add_development_dependency "rake"
   gem.add_development_dependency "simplecov"
-  gem.add_development_dependency "json"
-  gem.add_development_dependency 'rdoc'
   gem.add_development_dependency "yard"
+  gem.add_development_dependency "redcarpet"
 end

spec/build_tests_spec.rb

@@ -1,26 +1,53 @@
 require 'fileutils'
 
+class Dir
+  class << self
+    alias_method :orig_bracket, :[]
+  end
+  def self.[](*args)
+    orig_bracket(*args).sort
+  end
+end
+
 describe Rscons do
   BUILD_TEST_RUN_DIR = "build_test_run"
 
+  def rm_rf(dir)
+    FileUtils.rm_rf(dir)
+    if File.exists?(dir)
+      sleep 0.2
+      FileUtils.rm_rf(dir)
+      if File.exists?(dir)
+        sleep 0.5
+        FileUtils.rm_rf(dir)
+        if File.exists?(dir)
+          sleep 1.0
+          FileUtils.rm_rf(dir)
+          if File.exists?(dir)
+            raise "Could not remove #{dir}"
+          end
+        end
+      end
+    end
+  end
+
   before(:all) do
-    FileUtils.rm_rf(BUILD_TEST_RUN_DIR)
+    rm_rf(BUILD_TEST_RUN_DIR)
     @owd = Dir.pwd
   end
 
   before(:each) do
-    @output = ""
+    @saved_stdout = $stdout
-    $stdout.stub(:write) do |content|
+    $stdout = StringIO.new
-      @output += content
+    @saved_stderr = $stderr
-    end
+    $stderr = StringIO.new
-    $stderr.stub(:write) do |content|
-      @output += content
-    end
   end
 
   after(:each) do
+    $stdout = @saved_stdout
+    $stderr = @saved_stderr
     Dir.chdir(@owd)
-    FileUtils.rm_rf(BUILD_TEST_RUN_DIR)
+    rm_rf(BUILD_TEST_RUN_DIR)
   end
 
   def test_dir(build_test_directory)
@@ -34,15 +61,16 @@ describe Rscons do
     contents.each_line do |line|
       replaced += yield(line)
     end
-    File.open(fname, 'w') do |fh|
+    File.open(fname, 'wb') do |fh|
       fh.write(replaced)
     end
   end
 
   def lines
-    @output.lines.map(&:rstrip).tap do |v|
+    rv = ($stdout.string + $stderr.string).lines.map(&:rstrip)
-      @output = ""
+    $stdout.string = ""
-    end
+    $stderr.string = ""
+    rv
   end
 
   ###########################################################################
@@ -54,30 +82,30 @@ describe Rscons do
     Rscons::Environment.new do |env|
       env.Program('simple', Dir['*.c'])
     end
-    File.exists?('simple.o').should be_true
+    expect(File.exists?('simple.o')).to be_truthy
-    `./simple`.should == "This is a simple C program\n"
+    expect(`./simple`).to eq "This is a simple C program\n"
   end
 
   it 'prints commands as they are executed' do
     test_dir('simple')
-    Rscons::Environment.new(echo: :command) do |env|
+    env = Rscons::Environment.new(echo: :command) do |env|
       env["LD"] = "gcc"
       env.Program('simple', Dir['*.c'])
     end
-    lines.should == [
+    expect(lines).to eq [
       'gcc -c -o simple.o -MMD -MF simple.mf simple.c',
-      'gcc -o simple simple.o',
+      "gcc -o simple#{env["PROGSUFFIX"]} simple.o",
     ]
   end
 
   it 'prints short representations of the commands being executed' do
     test_dir('header')
-    Rscons::Environment.new do |env|
+    env = Rscons::Environment.new do |env|
       env.Program('header', Dir['*.c'])
     end
-    lines.should == [
+    expect(lines).to eq [
       'CC header.o',
-      'LD header',
+      "LD header#{env["PROGSUFFIX"]}",
     ]
   end
 
@@ -86,8 +114,8 @@ describe Rscons do
     Rscons::Environment.new do |env|
       env.Program('header', Dir['*.c'])
     end
-    File.exists?('header.o').should be_true
+    expect(File.exists?('header.o')).to be_truthy
-    `./header`.should == "The value is 2\n"
+    expect(`./header`).to eq "The value is 2\n"
   end
 
   it 'rebuilds a C module when a header it depends on changes' do
@@ -95,10 +123,10 @@ describe Rscons do
     env = Rscons::Environment.new do |env|
       env.Program('header', Dir['*.c'])
     end
-    `./header`.should == "The value is 2\n"
+    expect(`./header`).to eq "The value is 2\n"
     file_sub('header.h') {|line| line.sub(/2/, '5')}
     env.process
-    `./header`.should == "The value is 5\n"
+    expect(`./header`).to eq "The value is 5\n"
   end
 
   it 'does not rebuild a C module when its dependencies have not changed' do
@@ -106,44 +134,45 @@ describe Rscons do
     env = Rscons::Environment.new do |env|
       env.Program('header', Dir['*.c'])
     end
-    `./header`.should == "The value is 2\n"
+    expect(`./header`).to eq "The value is 2\n"
-    lines.should == [
+    expect(lines).to eq [
       'CC header.o',
-      'LD header',
+      "LD header#{env["PROGSUFFIX"]}",
     ]
     env.process
-    lines.should == []
+    expect(lines).to eq []
   end
 
-  it "does not rebuild a C module when only the file's timestampe has changed" do
+  it "does not rebuild a C module when only the file's timestamp has changed" do
     test_dir('header')
     env = Rscons::Environment.new do |env|
       env.Program('header', Dir['*.c'])
     end
-    `./header`.should == "The value is 2\n"
+    expect(`./header`).to eq "The value is 2\n"
-    lines.should == [
+    expect(lines).to eq [
       'CC header.o',
-      'LD header',
+      "LD header#{env["PROGSUFFIX"]}",
     ]
+    sleep 0.05
     file_sub('header.c') {|line| line}
     env.process
-    lines.should == []
+    expect(lines).to eq []
   end
 
   it 're-links a program when the link flags have changed' do
     test_dir('simple')
-    Rscons::Environment.new(echo: :command) do |env|
+    env = Rscons::Environment.new(echo: :command) do |env|
       env.Program('simple', Dir['*.c'])
     end
-    lines.should == [
+    expect(lines).to eq [
       'gcc -c -o simple.o -MMD -MF simple.mf simple.c',
-      'gcc -o simple simple.o',
+      "gcc -o simple#{env["PROGSUFFIX"]} simple.o",
     ]
-    Rscons::Environment.new(echo: :command) do |env|
+    e2 = Rscons::Environment.new(echo: :command) do |env|
-      env["LIBS"] += ["c"]
+      env["LIBPATH"] += ["libdir"]
       env.Program('simple', Dir['*.c'])
     end
-    lines.should == ['gcc -o simple simple.o -lc']
+    expect(lines).to eq ["gcc -o simple#{env["PROGSUFFIX"]} simple.o -Llibdir"]
   end
 
   it 'builds object files in a different build directory' do
@@ -153,20 +182,20 @@ describe Rscons do
       env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
       env.Program('build_dir', Dir['src/**/*.c'])
     end
-    `./build_dir`.should == "Hello from two()\n"
+    expect(`./build_dir`).to eq "Hello from two()\n"
-    File.exists?('build_one/one.o').should be_true
+    expect(File.exists?('build_one/one.o')).to be_truthy
-    File.exists?('build_two/two.o').should be_true
+    expect(File.exists?('build_two/two.o')).to be_truthy
   end
 
   it 'uses build directories before build root' do
     test_dir('build_dir')
-    Rscons::Environment.new do |env|
+    env = Rscons::Environment.new do |env|
       env.append('CPPPATH' => Dir['src/**/*/'])
       env.build_dir("src", "build")
       env.build_root = "build_root"
       env.Program('build_dir', Dir['src/**/*.c'])
     end
-    lines.should == ["CC build/one/one.o", "CC build/two/two.o", "LD build_dir"]
+    expect(lines).to eq ["CC build/one/one.o", "CC build/two/two.o", "LD build_dir#{env["PROGSUFFIX"]}"]
   end
 
   it 'uses build_root if no build directories match' do
@@ -175,9 +204,26 @@ describe Rscons do
       env.append('CPPPATH' => Dir['src/**/*/'])
       env.build_dir("src2", "build")
       env.build_root = "build_root"
-      env.Program('build_dir', Dir['src/**/*.c'])
+      env.Program('build_dir.exe', Dir['src/**/*.c'])
     end
-    lines.should == ["CC build_root/src/one/one.o", "CC build_root/src/two/two.o", "LD build_dir"]
+    expect(lines).to eq ["CC build_root/src/one/one.o", "CC build_root/src/two/two.o", "LD build_dir.exe"]
+  end
+
+  it "expands target and source paths starting with ^/ to be relative to the build root" do
+    test_dir('build_dir')
+    env = Rscons::Environment.new(echo: :command) do |env|
+      env.append('CPPPATH' => Dir['src/**/*/'])
+      env.build_root = "build_root"
+      FileUtils.mkdir_p(env.build_root)
+      FileUtils.mv("src/one/one.c", "build_root")
+      env.Object("^/one.o", "^/one.c")
+      env.Program('build_dir', Dir['src/**/*.c'] + ["^/one.o"])
+    end
+    expect(lines).to eq [
+      %q{gcc -c -o build_root/one.o -MMD -MF build_root/one.mf -Isrc/one/ -Isrc/two/ build_root/one.c},
+      %q{gcc -c -o build_root/src/two/two.o -MMD -MF build_root/src/two/two.mf -Isrc/one/ -Isrc/two/ src/two/two.c},
+      %Q{gcc -o build_dir#{env["PROGSUFFIX"]} build_root/src/two/two.o build_root/one.o},
+    ]
   end
 
   it 'cleans built files' do
@@ -187,15 +233,15 @@ describe Rscons do
       env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
       env.Program('build_dir', Dir['src/**/*.c'])
     end
-    `./build_dir`.should == "Hello from two()\n"
+    expect(`./build_dir`).to eq "Hello from two()\n"
-    File.exists?('build_one/one.o').should be_true
+    expect(File.exists?('build_one/one.o')).to be_truthy
-    File.exists?('build_two/two.o').should be_true
+    expect(File.exists?('build_two/two.o')).to be_truthy
     Rscons.clean
-    File.exists?('build_one/one.o').should be_false
+    expect(File.exists?('build_one/one.o')).to be_falsey
-    File.exists?('build_two/two.o').should be_false
+    expect(File.exists?('build_two/two.o')).to be_falsey
-    File.exists?('build_one').should be_false
+    expect(File.exists?('build_one')).to be_falsey
-    File.exists?('build_two').should be_false
+    expect(File.exists?('build_two')).to be_falsey
-    File.exists?('src/one/one.c').should be_true
+    expect(File.exists?('src/one/one.c')).to be_truthy
   end
 
   it 'does not clean created directories if other non-rscons-generated files reside there' do
@@ -205,16 +251,16 @@ describe Rscons do
       env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
       env.Program('build_dir', Dir['src/**/*.c'])
     end
-    `./build_dir`.should == "Hello from two()\n"
+    expect(`./build_dir`).to eq "Hello from two()\n"
-    File.exists?('build_one/one.o').should be_true
+    expect(File.exists?('build_one/one.o')).to be_truthy
-    File.exists?('build_two/two.o').should be_true
+    expect(File.exists?('build_two/two.o')).to be_truthy
     File.open('build_two/tmp', 'w') { |fh| fh.puts "dum" }
     Rscons.clean
-    File.exists?('build_one/one.o').should be_false
+    expect(File.exists?('build_one/one.o')).to be_falsey
-    File.exists?('build_two/two.o').should be_false
+    expect(File.exists?('build_two/two.o')).to be_falsey
-    File.exists?('build_one').should be_false
+    expect(File.exists?('build_one')).to be_falsey
-    File.exists?('build_two').should be_true
+    expect(File.exists?('build_two')).to be_truthy
-    File.exists?('src/one/one.c').should be_true
+    expect(File.exists?('src/one/one.c')).to be_truthy
   end
 
   it 'allows Ruby classes as custom builders to be used to construct files' do
@@ -230,15 +276,15 @@ EOF
       end
     end
 
-    Rscons::Environment.new do |env|
+    env = Rscons::Environment.new do |env|
       env.add_builder(MySource.new)
       env.MySource('inc.h', [])
       env.Program('program', Dir['*.c'])
     end
 
-    lines.should == ['CC program.o', 'LD program']
+    expect(lines).to eq ["CC program.o", "LD program#{env["PROGSUFFIX"]}"]
-    File.exists?('inc.h').should be_true
+    expect(File.exists?('inc.h')).to be_truthy
-    `./program`.should == "The value is 5678\n"
+    expect(`./program`).to eq "The value is 5678\n"
   end
 
   it 'supports custom builders with multiple targets' do
@@ -263,15 +309,15 @@ EOF
       env.Program("program", Dir["*.c"] + ["inc.c"])
     end
 
-    lines.should == ["CHGen inc.c", "CC program.o", "CC inc.o", "LD program"]
+    expect(lines).to eq ["CHGen inc.c", "CC program.o", "CC inc.o", "LD program#{env["PROGSUFFIX"]}"]
-    File.exists?("inc.c").should be_true
+    expect(File.exists?("inc.c")).to be_truthy
-    File.exists?("inc.h").should be_true
+    expect(File.exists?("inc.h")).to be_truthy
-    `./program`.should == "The value is 42\n"
+    expect(`./program`).to eq "The value is 42\n"
 
     File.open("inc.c", "w") {|fh| fh.puts "int THE_VALUE = 33;"}
     env.process
-    lines.should == ["CHGen inc.c"]
+    expect(lines).to eq ["CHGen inc.c"]
-    `./program`.should == "The value is 42\n"
+    expect(`./program`).to eq "The value is 42\n"
   end
 
   it 'allows cloning Environment objects' do
@@ -290,11 +336,34 @@ EOF
       env.Program('program-release', Dir['src/*.c'])
     end
 
-    lines.should == [
+    expect(lines).to eq [
       %q{gcc -c -o debug/program.o -MMD -MF debug/program.mf '-DSTRING="Debug Version"' -O2 src/program.c},
-      %q{gcc -o program-debug debug/program.o},
+      %Q{gcc -o program-debug#{debug["PROGSUFFIX"]} debug/program.o},
       %q{gcc -c -o release/program.o -MMD -MF release/program.mf '-DSTRING="Release Version"' -O2 src/program.c},
-      %q{gcc -o program-release release/program.o},
+      %Q{gcc -o program-release#{debug["PROGSUFFIX"]} release/program.o},
+    ]
+  end
+
+  it 'allows cloning all attributes of an Environment object' do
+    test_dir('clone_env')
+
+    env1 = Rscons::Environment.new(echo: :command) do |env|
+      env.build_dir('src', 'build')
+      env['CFLAGS'] = '-O2'
+      env.add_build_hook do |build_op|
+        build_op[:vars]['CPPFLAGS'] = '-DSTRING="Hello"'
+      end
+      env.Program('program', Dir['src/*.c'])
+    end
+
+    env2 = env1.clone(clone: :all) do |env|
+      env.Program('program2', Dir['src/*.c'])
+    end
+
+    expect(lines).to eq [
+      %q{gcc -c -o build/program.o -MMD -MF build/program.mf -DSTRING="Hello" -O2 src/program.c},
+      %Q{gcc -o program#{env1["PROGSUFFIX"]} build/program.o},
+      %Q{gcc -o program2#{env2["PROGSUFFIX"]} build/program.o},
     ]
   end
 
@@ -303,45 +372,45 @@ EOF
     Rscons::Environment.new do |env|
       env.Program('simple', Dir['*.cc'])
     end
-    File.exists?('simple.o').should be_true
+    expect(File.exists?('simple.o')).to be_truthy
-    `./simple`.should == "This is a simple C++ program\n"
+    expect(`./simple`).to eq "This is a simple C++ program\n"
   end
 
   it 'allows overriding construction variables for individual builder calls' do
     test_dir('two_sources')
-    Rscons::Environment.new(echo: :command) do |env|
+    env = Rscons::Environment.new(echo: :command) do |env|
       env.Object("one.o", "one.c", 'CPPFLAGS' => ['-DONE'])
       env.Program('two_sources', ['one.o', 'two.c'])
     end
-    lines.should == [
+    expect(lines).to eq [
       'gcc -c -o one.o -MMD -MF one.mf -DONE one.c',
       'gcc -c -o two.o -MMD -MF two.mf two.c',
-      'gcc -o two_sources one.o two.o',
+      "gcc -o two_sources#{env["PROGSUFFIX"]} one.o two.o",
     ]
-    File.exists?('two_sources').should be_true
+    expect(File.exists?("two_sources#{env["PROGSUFFIX"]}")).to be_truthy
-    `./two_sources`.should == "This is a C program with two sources.\n"
+    expect(`./two_sources`).to eq "This is a C program with two sources.\n"
   end
 
   it 'builds a static library archive' do
     test_dir('library')
-    Rscons::Environment.new(echo: :command) do |env|
+    env = Rscons::Environment.new(echo: :command) do |env|
       env.Program('library', ['lib.a', 'three.c'])
       env.Library("lib.a", ['one.c', 'two.c'], 'CPPFLAGS' => ['-Dmake_lib'])
     end
-    lines.should == [
+    expect(lines).to eq [
       'gcc -c -o one.o -MMD -MF one.mf -Dmake_lib one.c',
       'gcc -c -o two.o -MMD -MF two.mf -Dmake_lib two.c',
       'ar rcs lib.a one.o two.o',
       'gcc -c -o three.o -MMD -MF three.mf three.c',
-      'gcc -o library lib.a three.o',
+      "gcc -o library#{env["PROGSUFFIX"]} lib.a three.o",
     ]
-    File.exists?('library').should be_true
+    expect(File.exists?("library#{env["PROGSUFFIX"]}")).to be_truthy
-    `ar t lib.a`.should == "one.o\ntwo.o\n"
+    expect(`ar t lib.a`).to eq "one.o\ntwo.o\n"
   end
 
   it 'supports build hooks to override construction variables' do
     test_dir("build_dir")
-    Rscons::Environment.new(echo: :command) do |env|
+    env = Rscons::Environment.new(echo: :command) do |env|
       env.append('CPPPATH' => Dir['src/**/*/'])
       env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
       env.add_build_hook do |build_op|
@@ -351,58 +420,127 @@ EOF
           build_op[:vars]["CFLAGS"] << "-O2"
         end
       end
-      env.Program('build_hook', Dir['src/**/*.c'])
+      env.Program('build_hook.exe', Dir['src/**/*.c'])
     end
-    `./build_hook`.should == "Hello from two()\n"
+    expect(`./build_hook.exe`).to eq "Hello from two()\n"
-    lines.should =~ [
+    expect(lines).to match_array [
       'gcc -c -o build_one/one.o -MMD -MF build_one/one.mf -Isrc/one/ -Isrc/two/ -O1 src/one/one.c',
       'gcc -c -o build_two/two.o -MMD -MF build_two/two.mf -Isrc/one/ -Isrc/two/ -O2 src/two/two.c',
-      'gcc -o build_hook build_one/one.o build_two/two.o',
+      'gcc -o build_hook.exe build_one/one.o build_two/two.o',
     ]
   end
 
   it 'rebuilds when user-specified dependencies change' do
     test_dir('simple')
-    Rscons::Environment.new do |env|
+    env = Rscons::Environment.new do |env|
-      env.Program('simple', Dir['*.c'])
+      env.Program('simple.exe', Dir['*.c']).depends("file.ld")
       File.open("file.ld", "w") do |fh|
         fh.puts("foo")
       end
-      env.depends('simple', 'file.ld')
     end
-    lines.should == ["CC simple.o", "LD simple"]
+    expect(lines).to eq ["CC simple.o", "LD simple.exe"]
-    File.exists?('simple.o').should be_true
+    expect(File.exists?('simple.o')).to be_truthy
-    `./simple`.should == "This is a simple C program\n"
+    expect(`./simple.exe`).to eq "This is a simple C program\n"
-    Rscons::Environment.new do |env|
+    e2 = Rscons::Environment.new do |env|
-      env.Program('simple', Dir['*.c'])
+      program = env.Program('simple.exe', Dir['*.c'])
+      env.depends(program, "file.ld")
       File.open("file.ld", "w") do |fh|
         fh.puts("bar")
       end
-      env.depends('simple', 'file.ld')
     end
-    lines.should == ["LD simple"]
+    expect(lines).to eq ["LD simple.exe"]
-    Rscons::Environment.new do |env|
+    e3 = Rscons::Environment.new do |env|
-      env.Program('simple', Dir['*.c'])
+      env.Program('simple.exe', Dir['*.c'])
       File.unlink("file.ld")
     end
-    lines.should == ["LD simple"]
+    expect(lines).to eq ["LD simple.exe"]
     Rscons::Environment.new do |env|
-      env.Program('simple', Dir['*.c'])
+      env.Program('simple.exe', Dir['*.c'])
     end
-    lines.should == []
+    expect(lines).to eq []
   end
 
   unless ENV["omit_gdc_tests"]
     it "supports building D sources" do
       test_dir("d")
       Rscons::Environment.new(echo: :command) do |env|
-        env.Program("hello-d", Dir["*.d"])
+        env.Program("hello-d.exe", Dir["*.d"])
       end
-      lines.should == [
+      expect(lines).to eq [
         "gdc -c -o main.o main.d",
-        "gdc -o hello-d main.o",
+        "gdc -o hello-d.exe main.o",
       ]
-      `./hello-d`.rstrip.should == "Hello from D!"
+      expect(`./hello-d.exe`.rstrip).to eq "Hello from D!"
     end
   end
+
+  it "supports disassembling object files" do
+    test_dir("simple")
+    Rscons::Environment.new do |env|
+      env.Object("simple.o", "simple.c")
+      env.Disassemble("simple.txt", "simple.o")
+    end
+    expect(File.exists?("simple.txt")).to be_truthy
+    expect(File.read("simple.txt")).to match /Disassembly of section .text:/
+  end
+
+  it "supports preprocessing C sources" do
+    test_dir("simple")
+    Rscons::Environment.new do |env|
+      env.Preprocess("simplepp.c", "simple.c")
+      env.Program("simple", "simplepp.c")
+    end
+    expect(File.read("simplepp.c")).to match /# \d+ "simple.c"/
+    expect(`./simple`).to eq "This is a simple C program\n"
+  end
+
+  it "supports preprocessing C++ sources" do
+    test_dir("simple_cc")
+    Rscons::Environment.new do |env|
+      env.Preprocess("simplepp.cc", "simple.cc")
+      env.Program("simple", "simplepp.cc")
+    end
+    expect(File.read("simplepp.cc")).to match /# \d+ "simple.cc"/
+    expect(`./simple`).to eq "This is a simple C++ program\n"
+  end
+
+  it "supports invoking builders with no sources and a build_root defined" do
+    class TestBuilder < Rscons::Builder
+      def run(target, sources, cache, env, vars)
+        target
+      end
+    end
+    test_dir("simple")
+    Rscons::Environment.new do |env|
+      env.build_root = "build"
+      env.add_builder(TestBuilder.new)
+      env.TestBuilder("file")
+    end
+  end
+
+  it "expands construction variables in builder target and sources before invoking the builder" do
+    test_dir('custom_builder')
+    class MySource < Rscons::Builder
+      def run(target, sources, cache, env, vars)
+        File.open(target, 'w') do |fh|
+          fh.puts <<EOF
+    #define THE_VALUE 678
+EOF
+        end
+        target
+      end
+    end
+
+    env = Rscons::Environment.new do |env|
+      env["hdr"] = "inc.h"
+      env["src"] = "program.c"
+      env.add_builder(MySource.new)
+      env.MySource('${hdr}')
+      env.Program('program', "${src}")
+    end
+
+    expect(lines).to eq ["CC program.o", "LD program#{env["PROGSUFFIX"]}"]
+    expect(File.exists?('inc.h')).to be_truthy
+    expect(`./program`).to eq "The value is 678\n"
+  end
 end

spec/rscons/builders/cfile_spec.rb

@@ -0,0 +1,28 @@
+module Rscons
+  module Builders
+    describe CFile do
+      let(:env) {Environment.new}
+      subject {CFile.new}
+
+      it "invokes bison to create a .c file from a .y file" do
+        expect(subject).to receive(:standard_build).with("YACC parser.c", "parser.c", ["bison", "-d", "-o", "parser.c", "parser.y"], ["parser.y"], env, :cache)
+        subject.run("parser.c", ["parser.y"], :cache, env, {})
+      end
+
+      it "invokes a custom lexer to create a .cc file from a .ll file" do
+        env["LEX"] = "custom_lex"
+        expect(subject).to receive(:standard_build).with("LEX lexer.cc", "lexer.cc", ["custom_lex", "-o", "lexer.cc", "parser.ll"], ["parser.ll"], env, :cache)
+        subject.run("lexer.cc", ["parser.ll"], :cache, env, {})
+      end
+
+      it "supports overriding construction variables" do
+        expect(subject).to receive(:standard_build).with("LEX lexer.c", "lexer.c", ["hi", "parser.l"], ["parser.l"], env, :cache)
+        subject.run("lexer.c", ["parser.l"], :cache, env, "LEX_CMD" => ["hi", "${_SOURCES}"])
+      end
+
+      it "raises an error when an unknown source file is specified" do
+        expect {subject.run("file.c", ["foo.bar"], :cache, env, {})}.to raise_error /Unknown source file .foo.bar. for CFile builder/
+      end
+    end
+  end
+end

spec/rscons/builders/disassemble_spec.rb

@@ -0,0 +1,17 @@
+module Rscons
+  module Builders
+    describe Disassemble do
+      let(:env) {Environment.new}
+      subject {Disassemble.new}
+
+      it "supports overriding DISASM_CMD construction variable" do
+        cache = "cache"
+        allow(cache).to receive(:up_to_date?) { false }
+        allow(cache).to receive(:mkdir_p) { }
+        allow(cache).to receive(:register_build) { }
+        expect(env).to receive(:execute).with("Disassemble a_file.txt", ["my_disasm", "a_file.exe"], anything).and_return(true)
+        subject.run("a_file.txt", ["a_file.exe"], cache, env, "DISASM_CMD" => ["my_disasm", "${_SOURCES}"])
+      end
+    end
+  end
+end

spec/rscons/builders/library_spec.rb

@@ -0,0 +1,18 @@
+module Rscons
+  module Builders
+    describe Library do
+      let(:env) {Environment.new}
+      subject {Library.new}
+
+      it "supports overriding AR construction variable" do
+        expect(subject).to receive(:standard_build).with("AR prog.a", "prog.a", ["sp-ar", "rcs", "prog.a", "prog.o"], ["prog.o"], env, :cache)
+        subject.run("prog.a", ["prog.o"], :cache, env, "AR" => "sp-ar")
+      end
+
+      it "supports overriding ARCMD construction variable" do
+        expect(subject).to receive(:standard_build).with("AR prog.a", "prog.a", ["special", "AR!", "prog.o"], ["prog.o"], env, :cache)
+        subject.run("prog.a", ["prog.o"], :cache, env, "ARCMD" => ["special", "AR!", "${_SOURCES}"])
+      end
+    end
+  end
+end

spec/rscons/builders/object_spec.rb

@@ -0,0 +1,23 @@
+module Rscons
+  module Builders
+    describe Object do
+      let(:env) {Environment.new}
+      subject {Object.new}
+
+      it "supports overriding CCCMD construction variable" do
+        cache = "cache"
+        allow(cache).to receive(:up_to_date?) { false }
+        allow(cache).to receive(:mkdir_p) { }
+        allow(cache).to receive(:register_build) { }
+        allow(FileUtils).to receive(:rm_f) { }
+        allow(File).to receive(:exists?) { false }
+        expect(env).to receive(:execute).with("CC mod.o", ["llc", "mod.c"]).and_return(true)
+        subject.run("mod.o", ["mod.c"], cache, env, "CCCMD" => ["llc", "${_SOURCES}"])
+      end
+
+      it "raises an error when given a source file with an unknown suffix" do
+        expect { subject.run("mod.o", ["mod.xyz"], :cache, env, {}) }.to raise_error /unknown input file type: "mod.xyz"/
+      end
+    end
+  end
+end

spec/rscons/builders/preprocess_spec.rb

@@ -0,0 +1,18 @@
+module Rscons
+  module Builders
+    describe Preprocess do
+      let(:env) {Environment.new}
+      subject {Preprocess.new}
+
+      it "supports overriding CC construction variable" do
+        expect(subject).to receive(:standard_build).with("Preprocess module.pp", "module.pp", ["my_cpp", "-E", "-o", "module.pp", "module.c"], ["module.c"], env, :cache)
+        subject.run("module.pp", ["module.c"], :cache, env, "CC" => "my_cpp")
+      end
+
+      it "supports overriding CPP_CMD construction variable" do
+        expect(subject).to receive(:standard_build).with("Preprocess module.pp", "module.pp", ["my_cpp", "module.c"], ["module.c"], env, :cache)
+        subject.run("module.pp", ["module.c"], :cache, env, "CPP_CMD" => ["my_cpp", "${_SOURCES}"])
+      end
+    end
+  end
+end

spec/rscons/builders/program_spec.rb

@@ -0,0 +1,18 @@
+module Rscons
+  module Builders
+    describe Program do
+      let(:env) {Environment.new}
+      subject {Program.new}
+
+      it "supports overriding CC construction variable" do
+        expect(subject).to receive(:standard_build).with("LD prog", "prog", ["sp-c++", "-o", "prog", "prog.o"], ["prog.o"], env, :cache)
+        subject.run("prog", ["prog.o"], :cache, env, "CC" => "sp-c++")
+      end
+
+      it "supports overriding LDCMD construction variable" do
+        expect(subject).to receive(:standard_build).with("LD prog.exe", "prog.exe", ["special", "LD!", "prog.o"], ["prog.o"], env, :cache)
+        subject.run("prog.exe", ["prog.o"], :cache, env, "LDCMD" => ["special", "LD!", "${_SOURCES}"])
+      end
+    end
+  end
+end

spec/rscons/cache_spec.rb

@@ -1,171 +1,178 @@
 module Rscons
   describe Cache do
     before do
-      File.stub(:read) { nil }
+      allow(File).to receive(:read) { nil }
     end
 
     def build_from(cache)
-      YAML.should_receive(:load).and_return(cache)
+      allow(JSON).to receive(:load) do
-      Cache.new
+        cache
       end
-
+      Cache.instance.tap do |cache|
-    describe ".clear" do
+        cache.send(:initialize!)
-      it "removes the cache file" do
-        FileUtils.should_receive(:rm_f).with(Cache::CACHE_FILE)
-        Cache.clear
       end
     end
 
     describe "#initialize" do
       context "when corrupt" do
         it "prints a warning and defaults to an empty hash" do
-          YAML.should_receive(:load).and_return("string")
+          expect(JSON).to receive(:load).and_return("string")
-          $stderr.should_receive(:puts).with(/Warning:.*was.corrupt/)
+          expect($stderr).to receive(:puts).with(/Warning:.*was.corrupt/)
-          Cache.new.instance_variable_get(:@cache).is_a?(Hash).should be_true
+          c = Cache.instance
+          c.send(:initialize!)
+          expect(c.instance_variable_get(:@cache).is_a?(Hash)).to be_truthy
         end
       end
     end
 
+    describe "#clear" do
+      it "removes the cache file" do
+        expect(FileUtils).to receive(:rm_f).with(Cache::CACHE_FILE)
+        allow(JSON).to receive(:load) {{}}
+        Cache.instance.clear
+      end
+    end
+
     describe "#write" do
-      it "should fill in :version and write to file" do
+      it "fills in 'version' and write to file" do
         cache = {}
         fh = $stdout
-        fh.should_receive(:puts)
+        expect(fh).to receive(:puts)
-        File.should_receive(:open).and_yield(fh)
+        expect(File).to receive(:open).and_yield(fh)
         build_from(cache).write
-        cache[:version].should == Rscons::VERSION
+        expect(cache["version"]).to eq Rscons::VERSION
       end
     end
 
     describe "#up_to_date?" do
       empty_env = "env"
       before do
-        empty_env.stub(:get_user_deps) { nil }
+        allow(empty_env).to receive(:get_user_deps) { nil }
       end
 
       it "returns false when target file does not exist" do
-        File.should_receive(:exists?).with("target").and_return(false)
+        expect(File).to receive(:exists?).with("target").and_return(false)
-        build_from({}).up_to_date?("target", "command", [], empty_env).should be_false
+        expect(build_from({}).up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when target is not registered in the cache" do
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        build_from({}).up_to_date?("target", "command", [], empty_env).should be_false
+        expect(build_from({}).up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when the target's checksum does not match" do
-        _cache = {targets: {"target" => {checksum: "abc"}}}
+        _cache = {"targets" => {"target" => {"checksum" => "abc"}}}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("def")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("def")
-        cache.up_to_date?("target", "command", [], empty_env).should be_false
+        expect(cache.up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when the build command has changed" do
-        _cache = {targets: {"target" => {checksum: "abc", command: "old command"}}}
+        _cache = {"targets" => {"target" => {"checksum" => "abc", "command" => Digest::MD5.hexdigest("old command".inspect)}}}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.up_to_date?("target", "command", [], empty_env).should be_false
+        expect(cache.up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when there is a new dependency" do
-        _cache = {targets: {"target" => {checksum: "abc",
+        _cache = {"targets" => {"target" => {"checksum" => "abc",
-                                         command: "command",
+                                         "command" => Digest::MD5.hexdigest("command".inspect),
-                                         deps: [{fname: "dep.1"}]}}}
+                                         "deps" => [{"fname" => "dep.1"}]}}}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env).should be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_falsey
       end
 
       it "returns false when a dependency's checksum has changed" do
-        _cache = {targets: {"target" => {checksum: "abc",
+        _cache = {"targets" => {"target" => {"checksum" => "abc",
-                                         command: "command",
+                                         "command" => Digest::MD5.hexdigest("command".inspect),
-                                         deps: [{fname: "dep.1",
+                                         "deps" => [{"fname" => "dep.1",
-                                                 checksum: "dep.1.chk"},
+                                                 "checksum" => "dep.1.chk"},
-                                                {fname: "dep.2",
+                                                {"fname" => "dep.2",
-                                                 checksum: "dep.2.chk"},
+                                                 "checksum" => "dep.2.chk"},
-                                                {fname: "extra.dep",
+                                                {"fname" => "extra.dep",
-                                                 checksum: "extra.dep.chk"}],
+                                                 "checksum" => "extra.dep.chk"}],
-                                         user_deps: []}}}
+                                         "user_deps" => []}}}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.should_receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
+        expect(cache).to receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
-        cache.should_receive(:calculate_checksum).with("dep.2").and_return("dep.2.changed")
+        expect(cache).to receive(:calculate_checksum).with("dep.2").and_return("dep.2.changed")
-        cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env).should be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_falsey
       end
 
       it "returns false with strict_deps=true when cache has an extra dependency" do
-        _cache = {targets: {"target" => {checksum: "abc",
+        _cache = {"targets" => {"target" => {"checksum" => "abc",
-                                         command: "command",
+                                         "command" => Digest::MD5.hexdigest("command".inspect),
-                                         deps: [{fname: "dep.1",
+                                         "deps" => [{"fname" => "dep.1",
-                                                 checksum: "dep.1.chk"},
+                                                 "checksum" => "dep.1.chk"},
-                                                {fname: "dep.2",
+                                                {"fname" => "dep.2",
-                                                 checksum: "dep.2.chk"},
+                                                 "checksum" => "dep.2.chk"},
-                                                {fname: "extra.dep",
+                                                {"fname" => "extra.dep",
-                                                 checksum: "extra.dep.chk"}],
+                                                 "checksum" => "extra.dep.chk"}],
-                                         user_deps: []}}}
+                                         "user_deps" => []}}}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env, strict_deps: true).should be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env, strict_deps: true)).to be_falsey
       end
 
       it "returns false when there is a new user dependency" do
-        _cache = {targets: {"target" => {checksum: "abc",
+        _cache = {"targets" => {"target" => {"checksum" => "abc",
-                                         command: "command",
+                                         "command" => Digest::MD5.hexdigest("command".inspect),
-                                         deps: [{fname: "dep.1"}],
+                                         "deps" => [{"fname" => "dep.1"}],
-                                         user_deps: []}}}
+                                         "user_deps" => []}}}
         cache = build_from(_cache)
         env = "env"
-        env.should_receive(:get_user_deps).with("target").and_return(["file.ld"])
+        expect(env).to receive(:get_user_deps).with("target").and_return(["file.ld"])
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.up_to_date?("target", "command", ["dep.1"], env).should be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1"], env)).to be_falsey
       end
 
       it "returns false when a user dependency checksum has changed" do
-        _cache = {targets: {"target" => {checksum: "abc",
+        _cache = {"targets" => {"target" => {"checksum" => "abc",
-                                         command: "command",
+                                         "command" => Digest::MD5.hexdigest("command".inspect),
-                                         deps: [{fname: "dep.1",
+                                         "deps" => [{"fname" => "dep.1",
-                                                 checksum: "dep.1.chk"},
+                                                 "checksum" => "dep.1.chk"},
-                                                {fname: "dep.2",
+                                                {"fname" => "dep.2",
-                                                 checksum: "dep.2.chk"},
+                                                 "checksum" => "dep.2.chk"},
-                                                {fname: "extra.dep",
+                                                {"fname" => "extra.dep",
-                                                 checksum: "extra.dep.chk"}],
+                                                 "checksum" => "extra.dep.chk"}],
-                                         user_deps: [{fname: "user.dep",
+                                         "user_deps" => [{"fname" => "user.dep",
-                                                      checksum: "user.dep.chk"}]}}}
+                                                      "checksum" => "user.dep.chk"}]}}}
         cache = build_from(_cache)
         env = "env"
-        env.should_receive(:get_user_deps).with("target").and_return(["user.dep"])
+        expect(env).to receive(:get_user_deps).with("target").and_return(["user.dep"])
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.should_receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
+        expect(cache).to receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
-        cache.should_receive(:calculate_checksum).with("dep.2").and_return("dep.2.chk")
+        expect(cache).to receive(:calculate_checksum).with("dep.2").and_return("dep.2.chk")
-        cache.should_receive(:calculate_checksum).with("extra.dep").and_return("extra.dep.chk")
+        expect(cache).to receive(:calculate_checksum).with("extra.dep").and_return("extra.dep.chk")
-        cache.should_receive(:calculate_checksum).with("user.dep").and_return("INCORRECT")
+        expect(cache).to receive(:calculate_checksum).with("user.dep").and_return("INCORRECT")
-        cache.up_to_date?("target", "command", ["dep.1", "dep.2"], env).should be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], env)).to be_falsey
       end
 
       it "returns true when no condition for false is met" do
-        _cache = {targets: {"target" => {checksum: "abc",
+        _cache = {"targets" => {"target" => {"checksum" => "abc",
-                                         command: "command",
+                                         "command" => Digest::MD5.hexdigest("command".inspect),
-                                         deps: [{fname: "dep.1",
+                                         "deps" => [{"fname" => "dep.1",
-                                                 checksum: "dep.1.chk"},
+                                                 "checksum" => "dep.1.chk"},
-                                                {fname: "dep.2",
+                                                {"fname" => "dep.2",
-                                                 checksum: "dep.2.chk"},
+                                                 "checksum" => "dep.2.chk"},
-                                                {fname: "extra.dep",
+                                                {"fname" => "extra.dep",
-                                                 checksum: "extra.dep.chk"}],
+                                                 "checksum" => "extra.dep.chk"}],
-                                         user_deps: []}}}
+                                         "user_deps" => []}}}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("target").and_return(true)
+        expect(File).to receive(:exists?).with("target").and_return(true)
-        cache.should_receive(:calculate_checksum).with("target").and_return("abc")
+        expect(cache).to receive(:calculate_checksum).with("target").and_return("abc")
-        cache.should_receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
+        expect(cache).to receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
-        cache.should_receive(:calculate_checksum).with("dep.2").and_return("dep.2.chk")
+        expect(cache).to receive(:calculate_checksum).with("dep.2").and_return("dep.2.chk")
-        cache.should_receive(:calculate_checksum).with("extra.dep").and_return("extra.dep.chk")
+        expect(cache).to receive(:calculate_checksum).with("extra.dep").and_return("extra.dep.chk")
-        cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env).should be_true
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_truthy
       end
     end
 
@@ -174,30 +181,30 @@ module Rscons
         _cache = {}
         cache = build_from(_cache)
         env = "env"
-        env.should_receive(:get_user_deps).with("the target").and_return(["user.dep"])
+        expect(env).to receive(:get_user_deps).with("the target").and_return(["user.dep"])
-        cache.should_receive(:calculate_checksum).with("the target").and_return("the checksum")
+        expect(cache).to receive(:calculate_checksum).with("the target").and_return("the checksum")
-        cache.should_receive(:calculate_checksum).with("dep 1").and_return("dep 1 checksum")
+        expect(cache).to receive(:calculate_checksum).with("dep 1").and_return("dep 1 checksum")
-        cache.should_receive(:calculate_checksum).with("dep 2").and_return("dep 2 checksum")
+        expect(cache).to receive(:calculate_checksum).with("dep 2").and_return("dep 2 checksum")
-        cache.should_receive(:calculate_checksum).with("user.dep").and_return("user.dep checksum")
+        expect(cache).to receive(:calculate_checksum).with("user.dep").and_return("user.dep checksum")
         cache.register_build("the target", "the command", ["dep 1", "dep 2"], env)
-        cached_target = cache.instance_variable_get(:@cache)[:targets]["the target"]
+        cached_target = cache.instance_variable_get(:@cache)["targets"]["the target"]
-        cached_target.should_not be_nil
+        expect(cached_target).to_not be_nil
-        cached_target[:command].should == "the command"
+        expect(cached_target["command"]).to eq Digest::MD5.hexdigest("the command".inspect)
-        cached_target[:checksum].should == "the checksum"
+        expect(cached_target["checksum"]).to eq "the checksum"
-        cached_target[:deps].should == [
+        expect(cached_target["deps"]).to eq [
-          {fname: "dep 1", checksum: "dep 1 checksum"},
+          {"fname" => "dep 1", "checksum" => "dep 1 checksum"},
-          {fname: "dep 2", checksum: "dep 2 checksum"},
+          {"fname" => "dep 2", "checksum" => "dep 2 checksum"},
         ]
-        cached_target[:user_deps].should == [
+        expect(cached_target["user_deps"]).to eq [
-          {fname: "user.dep", checksum: "user.dep checksum"},
+          {"fname" => "user.dep", "checksum" => "user.dep checksum"},
         ]
       end
     end
 
     describe "#targets" do
       it "returns a list of targets that are cached" do
-        cache = {targets: {"t1" => {}, "t2" => {}, "t3" => {}}}
+        cache = {"targets" => {"t1" => {}, "t2" => {}, "t3" => {}}}
-        build_from(cache).targets.should == ["t1", "t2", "t3"]
+        expect(build_from(cache).targets).to eq ["t1", "t2", "t3"]
       end
     end
 
@@ -205,25 +212,35 @@ module Rscons
       it "makes directories and records any created in the cache" do
         _cache = {}
         cache = build_from(_cache)
-        File.should_receive(:exists?).with("one").and_return(true)
+        expect(File).to receive(:exists?).with("one").and_return(true)
-        File.should_receive(:exists?).with("one/two").and_return(false)
+        expect(File).to receive(:exists?).with("one/two").and_return(false)
-        FileUtils.should_receive(:mkdir).with("one/two")
+        expect(FileUtils).to receive(:mkdir).with("one/two")
-        File.should_receive(:exists?).with("one/two/three").and_return(false)
+        expect(File).to receive(:exists?).with("one/two/three").and_return(false)
-        FileUtils.should_receive(:mkdir).with("one/two/three")
+        expect(FileUtils).to receive(:mkdir).with("one/two/three")
-        File.should_receive(:exists?).with("one").and_return(true)
+        expect(File).to receive(:exists?).with("one").and_return(true)
-        File.should_receive(:exists?).with("one/two").and_return(true)
+        expect(File).to receive(:exists?).with("one/two").and_return(true)
-        File.should_receive(:exists?).with("one/two/four").and_return(false)
+        expect(File).to receive(:exists?).with("one/two/four").and_return(false)
-        FileUtils.should_receive(:mkdir).with("one/two/four")
+        expect(FileUtils).to receive(:mkdir).with("one/two/four")
         cache.mkdir_p("one/two/three")
         cache.mkdir_p("one\\two\\four")
-        cache.directories.should == ["one/two", "one/two/three", "one/two/four"]
+        expect(cache.directories).to eq ["one/two", "one/two/three", "one/two/four"]
+      end
+
+      it "handles absolute paths" do
+        _cache = {}
+        cache = build_from(_cache)
+        expect(File).to receive(:exists?).with("/one").and_return(true)
+        expect(File).to receive(:exists?).with("/one/two").and_return(false)
+        expect(FileUtils).to receive(:mkdir).with("/one/two")
+        cache.mkdir_p("/one/two")
+        expect(cache.directories).to eq ["/one/two"]
       end
     end
 
     describe "#directories" do
       it "returns a list of directories that are cached" do
-        _cache = {directories: {"dir1" => true, "dir2" => true}}
+        _cache = {"directories" => {"dir1" => true, "dir2" => true}}
-        build_from(_cache).directories.should == ["dir1", "dir2"]
+        expect(build_from(_cache).directories).to eq ["dir1", "dir2"]
       end
     end
 
@@ -231,23 +248,23 @@ module Rscons
       it "does not re-calculate the checksum when it is already cached" do
         cache = build_from({})
         cache.instance_variable_set(:@lookup_checksums, {"f1" => "f1.chk"})
-        cache.should_not_receive(:calculate_checksum)
+        expect(cache).to_not receive(:calculate_checksum)
-        cache.send(:lookup_checksum, "f1").should == "f1.chk"
+        expect(cache.send(:lookup_checksum, "f1")).to eq "f1.chk"
       end
 
       it "calls calculate_checksum when the checksum is not cached" do
         cache = build_from({})
-        cache.should_receive(:calculate_checksum).with("f1").and_return("ck")
+        expect(cache).to receive(:calculate_checksum).with("f1").and_return("ck")
-        cache.send(:lookup_checksum, "f1").should == "ck"
+        expect(cache.send(:lookup_checksum, "f1")).to eq "ck"
       end
     end
 
     describe "#calculate_checksum" do
       it "calculates the MD5 of the file contents" do
         contents = "contents"
-        File.should_receive(:read).with("fname", mode: "rb").and_return(contents)
+        expect(File).to receive(:read).with("fname", mode: "rb").and_return(contents)
-        Digest::MD5.should_receive(:hexdigest).with(contents).and_return("the_checksum")
+        expect(Digest::MD5).to receive(:hexdigest).with(contents).and_return("the_checksum")
-        build_from({}).send(:calculate_checksum, "fname").should == "the_checksum"
+        expect(build_from({}).send(:calculate_checksum, "fname")).to eq "the_checksum"
       end
     end
   end

spec/rscons/environment_spec.rb

@@ -3,42 +3,63 @@ module Rscons
     describe "#initialize" do
       it "adds the default builders when they are not excluded" do
         env = Environment.new
-        env.builders.size.should be > 0
+        expect(env.builders.size).to be > 0
-        env.builders.map {|name, builder| builder.is_a?(Builder)}.all?.should be_true
+        expect(env.builders.map {|name, builder| builder.is_a?(Builder)}.all?).to be_truthy
-        env.builders.find {|name, builder| name == "Object"}.should_not be_nil
+        expect(env.builders.find {|name, builder| name == "Object"}).to_not be_nil
-        env.builders.find {|name, builder| name == "Program"}.should_not be_nil
+        expect(env.builders.find {|name, builder| name == "Program"}).to_not be_nil
-        env.builders.find {|name, builder| name == "Library"}.should_not be_nil
+        expect(env.builders.find {|name, builder| name == "Library"}).to_not be_nil
       end
 
       it "excludes the default builders with exclude_builders: :all" do
         env = Environment.new(exclude_builders: true)
-        env.builders.size.should == 0
+        expect(env.builders.size).to eq 0
       end
 
       context "when a block is given" do
         it "yields self and invokes #process()" do
           env = Environment.new do |env|
-            env.should_receive(:process)
+            expect(env).to receive(:process)
           end
         end
       end
     end
 
     describe "#clone" do
-      it 'should create unique copies of each construction variable' do
+      it 'creates unique copies of each construction variable' do
         env = Environment.new
         env["CPPPATH"] << "path1"
         env2 = env.clone
         env2["CPPPATH"] << "path2"
-        env["CPPPATH"].should == ["path1"]
+        expect(env["CPPPATH"]).to eq ["path1"]
-        env2["CPPPATH"].should == ["path1", "path2"]
+        expect(env2["CPPPATH"]).to eq ["path1", "path2"]
+      end
+
+      it "supports nil, false, true, String, Symbol, Array, Hash, and Integer variables" do
+        env = Environment.new
+        env["nil"] = nil
+        env["false"] = false
+        env["true"] = true
+        env["String"] = "String"
+        env["Symbol"] = :Symbol
+        env["Array"] = ["a", "b"]
+        env["Hash"] = {"a" => "b"}
+        env["Integer"] = 1234
+        env2 = env.clone
+        expect(env2["nil"]).to be_nil
+        expect(env2["false"].object_id).to eq(false.object_id)
+        expect(env2["true"].object_id).to eq(true.object_id)
+        expect(env2["String"]).to eq("String")
+        expect(env2["Symbol"]).to eq(:Symbol)
+        expect(env2["Array"]).to eq(["a", "b"])
+        expect(env2["Hash"]).to eq({"a" => "b"})
+        expect(env2["Integer"]).to eq(1234)
       end
 
       context "when a block is given" do
         it "yields self and invokes #process()" do
           env = Environment.new
           env.clone do |env2|
-            env2.should_receive(:process)
+            expect(env2).to receive(:process)
           end
         end
       end
@@ -47,9 +68,9 @@ module Rscons
     describe "#add_builder" do
       it "adds the builder to the list of builders" do
         env = Environment.new(exclude_builders: true)
-        env.builders.keys.should == []
+        expect(env.builders.keys).to eq []
         env.add_builder(Rscons::Builders::Object.new)
-        env.builders.keys.should == ["Object"]
+        expect(env.builders.keys).to eq ["Object"]
       end
     end
 
@@ -57,20 +78,20 @@ module Rscons
       context "with no build directories" do
         it "returns the name of the source file with suffix changed" do
           env = Environment.new
-          env.get_build_fname("src/dir/file.c", ".o").should == "src/dir/file.o"
+          expect(env.get_build_fname("src/dir/file.c", ".o")).to eq "src/dir/file.o"
-          env.get_build_fname("src\\dir\\other.d", ".a").should == "src/dir/other.a"
+          expect(env.get_build_fname("src\\dir\\other.d", ".a")).to eq "src/dir/other.a"
-          env.get_build_fname("source.cc", ".o").should == "source.o"
+          expect(env.get_build_fname("source.cc", ".o")).to eq "source.o"
         end
 
         context "with a build_root" do
           it "uses the build_root unless the path is absolute" do
             env = Environment.new
             env.build_root = "build/proj"
-            env.get_build_fname("src/dir/file.c", ".o").should == "build/proj/src/dir/file.o"
+            expect(env.get_build_fname("src/dir/file.c", ".o")).to eq "build/proj/src/dir/file.o"
-            env.get_build_fname("/some/lib.c", ".a").should == "/some/lib.a"
+            expect(env.get_build_fname("/some/lib.c", ".a")).to eq "/some/lib.a"
-            env.get_build_fname("C:\\abspath\\mod.cc", ".o").should == "C:/abspath/mod.o"
+            expect(env.get_build_fname("C:\\abspath\\mod.cc", ".o")).to eq "C:/abspath/mod.o"
-            env.get_build_fname("build\\proj\\generated.c", ".o").should == "build/proj/generated.o"
+            expect(env.get_build_fname("build\\proj\\generated.c", ".o")).to eq "build/proj/generated.o"
-            env.get_build_fname("build/proj.XX", ".yy").should == "build/proj/build/proj.yy"
+            expect(env.get_build_fname("build/proj.XX", ".yy")).to eq "build/proj/build/proj.yy"
           end
         end
       end
@@ -80,10 +101,10 @@ module Rscons
           env = Environment.new
           env.build_dir("src", "bld")
           env.build_dir(%r{^libs/([^/]+)}, 'build/libs/\1')
-          env.get_build_fname("src/input.cc", ".o").should == "bld/input.o"
+          expect(env.get_build_fname("src/input.cc", ".o")).to eq "bld/input.o"
-          env.get_build_fname("libs/lib1/some/file.c", ".o").should == "build/libs/lib1/some/file.o"
+          expect(env.get_build_fname("libs/lib1/some/file.c", ".o")).to eq "build/libs/lib1/some/file.o"
-          env.get_build_fname("libs/otherlib/otherlib.cc", ".o").should == "build/libs/otherlib/otherlib.o"
+          expect(env.get_build_fname("libs/otherlib/otherlib.cc", ".o")).to eq "build/libs/otherlib/otherlib.o"
-          env.get_build_fname("other_directory/o.d", ".a").should == "other_directory/o.a"
+          expect(env.get_build_fname("other_directory/o.d", ".a")).to eq "other_directory/o.a"
         end
 
         context "with a build_root" do
@@ -93,11 +114,11 @@ module Rscons
             env.build_dir(%r{^libs/([^/]+)}, 'build/libs/\1')
             env.build_root = "bldit"
 
-            env.get_build_fname("src/input.cc", ".o").should == "bld/input.o"
+            expect(env.get_build_fname("src/input.cc", ".o")).to eq "bld/input.o"
-            env.get_build_fname("libs/lib1/some/file.c", ".o").should == "build/libs/lib1/some/file.o"
+            expect(env.get_build_fname("libs/lib1/some/file.c", ".o")).to eq "build/libs/lib1/some/file.o"
-            env.get_build_fname("libs/otherlib/otherlib.cc", ".o").should == "build/libs/otherlib/otherlib.o"
+            expect(env.get_build_fname("libs/otherlib/otherlib.cc", ".o")).to eq "build/libs/otherlib/otherlib.o"
-            env.get_build_fname("other_directory/o.d", ".a").should == "bldit/other_directory/o.a"
+            expect(env.get_build_fname("other_directory/o.d", ".a")).to eq "bldit/other_directory/o.a"
-            env.get_build_fname("bldit/some/mod.d", ".a").should == "bldit/some/mod.a"
+            expect(env.get_build_fname("bldit/some/mod.d", ".a")).to eq "bldit/some/mod.a"
           end
         end
       end
@@ -107,7 +128,7 @@ module Rscons
       it "allows reading construction variables" do
         env = Environment.new
         env["CFLAGS"] = ["-g", "-Wall"]
-        env["CFLAGS"].should == ["-g", "-Wall"]
+        expect(env["CFLAGS"]).to eq ["-g", "-Wall"]
       end
     end
 
@@ -117,9 +138,9 @@ module Rscons
         env["CFLAGS"] = ["-g", "-Wall"]
         env["CFLAGS"] -= ["-g"]
         env["CFLAGS"] += ["-O3"]
-        env["CFLAGS"].should == ["-Wall", "-O3"]
+        expect(env["CFLAGS"]).to eq ["-Wall", "-O3"]
         env["other_var"] = "val33"
-        env["other_var"].should == "val33"
+        expect(env["other_var"]).to eq "val33"
       end
     end
 
@@ -129,8 +150,8 @@ module Rscons
         env["CFLAGS"] = ["-g"]
         env["CPPPATH"] = ["inc"]
         env.append("CFLAGS" => ["-Wall"], "CPPPATH" => ["include"])
-        env["CFLAGS"].should == ["-Wall"]
+        expect(env["CFLAGS"]).to eq ["-Wall"]
-        env["CPPPATH"].should == ["include"]
+        expect(env["CPPPATH"]).to eq ["include"]
       end
     end
 
@@ -140,9 +161,10 @@ module Rscons
         env.Program("a.out", "main.c")
 
         cache = "cache"
-        Cache.should_receive(:new).and_return(cache)
+        expect(Cache).to receive(:instance).and_return(cache)
-        env.should_receive(:run_builder).with(anything, "a.out", ["main.c"], cache, {}).and_return(true)
+        expect(cache).to receive(:clear_checksum_cache!)
-        cache.should_receive(:write)
+        expect(env).to receive(:run_builder).with(anything, "a.out", ["main.c"], cache, {}).and_return(true)
+        expect(cache).to receive(:write)
 
         env.process
       end
@@ -153,10 +175,11 @@ module Rscons
         env.Object("main.o", "other.cc")
 
         cache = "cache"
-        Cache.should_receive(:new).and_return(cache)
+        expect(Cache).to receive(:instance).and_return(cache)
-        env.should_receive(:run_builder).with(anything, "main.o", ["other.cc"], cache, {}).and_return("main.o")
+        expect(cache).to receive(:clear_checksum_cache!)
-        env.should_receive(:run_builder).with(anything, "a.out", ["main.o"], cache, {}).and_return("a.out")
+        expect(env).to receive(:run_builder).with(anything, "main.o", ["other.cc"], cache, {}).and_return("main.o")
-        cache.should_receive(:write)
+        expect(env).to receive(:run_builder).with(anything, "a.out", ["main.o"], cache, {}).and_return("a.out")
+        expect(cache).to receive(:write)
 
         env.process
       end
@@ -167,12 +190,28 @@ module Rscons
         env.Object("main.o", "other.cc")
 
         cache = "cache"
-        Cache.should_receive(:new).and_return(cache)
+        expect(Cache).to receive(:instance).and_return(cache)
-        env.should_receive(:run_builder).with(anything, "main.o", ["other.cc"], cache, {}).and_return(false)
+        expect(cache).to receive(:clear_checksum_cache!)
-        cache.should_receive(:write)
+        expect(env).to receive(:run_builder).with(anything, "main.o", ["other.cc"], cache, {}).and_return(false)
+        expect(cache).to receive(:write)
 
         expect { env.process }.to raise_error BuildError, /Failed.to.build.main.o/
       end
+
+      it "writes the cache when the Builder raises an exception" do
+        env = Environment.new
+        env.Object("module.o", "module.c")
+
+        cache = "cache"
+        expect(Cache).to receive(:instance).and_return(cache)
+        expect(cache).to receive(:clear_checksum_cache!)
+        allow(env).to receive(:run_builder) do |builder, target, sources, cache, vars|
+          raise "Ruby exception thrown by builder"
+        end
+        expect(cache).to receive(:write)
+
+        expect { env.process }.to raise_error RuntimeError, /Ruby exception thrown by builder/
+      end
     end
 
     describe "#clear_targets" do
@@ -195,7 +234,7 @@ module Rscons
         env["specialflag"] = "-z"
         template = ["cmd", "-I${path}", "${flags}", "${_source}", "${_dest}"]
         cmd = env.build_command(template, "_source" => "infile", "_dest" => "outfile")
-        cmd.should == ["cmd", "-Idir1", "-Idir2", "-x", "-y", "-z", "infile", "outfile"]
+        expect(cmd).to eq ["cmd", "-Idir1", "-Idir2", "-x", "-y", "-z", "infile", "outfile"]
       end
     end
 
@@ -205,11 +244,12 @@ module Rscons
         env["path"] = ["dir1", "dir2"]
         env["flags"] = ["-x", "-y", "${specialflag}"]
         env["specialflag"] = "-z"
-        env.expand_varref(["-p${path}", "${flags}"]).should == ["-pdir1", "-pdir2", "-x", "-y", "-z"]
+        env["foo"] = {}
-        env.expand_varref("foo").should == "foo"
+        expect(env.expand_varref(["-p${path}", "${flags}"])).to eq ["-pdir1", "-pdir2", "-x", "-y", "-z"]
+        expect(env.expand_varref("foo")).to eq "foo"
         expect {env.expand_varref("${foo}")}.to raise_error /expand.a.variable.reference/
-        env.expand_varref("${specialflag}").should == "-z"
+        expect(env.expand_varref("${specialflag}")).to eq "-z"
-        env.expand_varref("${path}").should == ["dir1", "dir2"]
+        expect(env.expand_varref("${path}")).to eq ["dir1", "dir2"]
       end
     end
 
@@ -218,8 +258,8 @@ module Rscons
         context "with no errors" do
           it "prints the short description and executes the command" do
             env = Environment.new(echo: :short)
-            env.should_receive(:puts).with("short desc")
+            expect(env).to receive(:puts).with("short desc")
-            env.should_receive(:system).with("a", "command", {}).and_return(true)
+            expect(env).to receive(:system).with(*Rscons.command_executer, "a", "command").and_return(true)
             env.execute("short desc", ["a", "command"])
           end
         end
@@ -227,10 +267,10 @@ module Rscons
         context "with errors" do
           it "prints the short description, executes the command, and prints the failed command line" do
             env = Environment.new(echo: :short)
-            env.should_receive(:puts).with("short desc")
+            expect(env).to receive(:puts).with("short desc")
-            env.should_receive(:system).with("a", "command", {}).and_return(false)
+            expect(env).to receive(:system).with(*Rscons.command_executer, "a", "command").and_return(false)
-            $stdout.should_receive(:write).with("Failed command was: ")
+            expect($stdout).to receive(:write).with("Failed command was: ")
-            env.should_receive(:puts).with("a command")
+            expect(env).to receive(:puts).with("a command")
             env.execute("short desc", ["a", "command"])
           end
         end
@@ -239,9 +279,9 @@ module Rscons
       context "with echo: :command" do
         it "prints the command executed and executes the command" do
           env = Environment.new(echo: :command)
-          env.should_receive(:puts).with("a command '--arg=val with spaces'")
+          expect(env).to receive(:puts).with("a command '--arg=val with spaces'")
-          env.should_receive(:system).with("a", "command", "--arg=val with spaces", opt: :val).and_return(false)
+          expect(env).to receive(:system).with({modified: :environment}, *Rscons.command_executer, "a", "command", "--arg=val with spaces", {opt: :val}).and_return(false)
-          env.execute("short desc", ["a", "command", "--arg=val with spaces"], opt: :val)
+          env.execute("short desc", ["a", "command", "--arg=val with spaces"], env: {modified: :environment}, options: {opt: :val})
         end
       end
     end
@@ -249,20 +289,19 @@ module Rscons
     describe "#method_missing" do
       it "calls the original method missing when the target method is not a known builder" do
         env = Environment.new
-        env.should_receive(:orig_method_missing).with(:foobar)
+        expect {env.foobar}.to raise_error /undefined method .foobar./
-        env.foobar
       end
 
       it "records the target when the target method is a known builder" do
         env = Environment.new
-        env.instance_variable_get(:@targets).should == {}
+        expect(env.instance_variable_get(:@targets)).to eq({})
-        env.Program("target", ["src1", "src2"], var: "val")
+        env.Object("target.o", ["src1.c", "src2.c"], var: "val")
-        target = env.instance_variable_get(:@targets)["target"]
+        target = env.instance_variable_get(:@targets)["target.o"]
-        target.should_not be_nil
+        expect(target).to_not be_nil
-        target[:builder].is_a?(Builder).should be_true
+        expect(target[:builder].is_a?(Builder)).to be_truthy
-        target[:source].should == ["src1", "src2"]
+        expect(target[:sources]).to eq ["src1.c", "src2.c"]
-        target[:vars].should == {var: "val"}
+        expect(target[:vars]).to eq({var: "val"})
-        target[:args].should == []
+        expect(target[:args]).to eq []
       end
 
       it "raises an error when vars is not a Hash" do
@@ -275,13 +314,13 @@ module Rscons
       it "records the given dependencies in @user_deps" do
         env = Environment.new
         env.depends("foo", "bar", "baz")
-        env.instance_variable_get(:@user_deps).should == {"foo" => ["bar", "baz"]}
+        expect(env.instance_variable_get(:@user_deps)).to eq({"foo" => ["bar", "baz"]})
       end
       it "records user dependencies only once" do
         env = Environment.new
         env.instance_variable_set(:@user_deps, {"foo" => ["bar"]})
         env.depends("foo", "bar", "baz")
-        env.instance_variable_get(:@user_deps).should == {"foo" => ["bar", "baz"]}
+        expect(env.instance_variable_get(:@user_deps)).to eq({"foo" => ["bar", "baz"]})
       end
     end
 
@@ -296,9 +335,9 @@ module Rscons
         cache = "cache"
         env = Environment.new
         env.add_builder(ABuilder.new)
-        env.builders["Object"].should_receive(:run).with("mod.o", ["mod.c"], cache, env, anything).and_return("mod.o")
+        expect(env.builders["Object"]).to receive(:run).with("mod.o", ["mod.c"], cache, env, anything).and_return("mod.o")
-        env.builders["ABuilder"].should_receive(:run).with("mod2.ab_out", ["mod2.ab_in"], cache, env, anything).and_return("mod2.ab_out")
+        expect(env.builders["ABuilder"]).to receive(:run).with("mod2.ab_out", ["mod2.ab_in"], cache, env, anything).and_return("mod2.ab_out")
-        env.build_sources(["precompiled.o", "mod.c", "mod2.ab_in"], [".o", ".ab_out"], cache, {}).should == ["precompiled.o", "mod.o", "mod2.ab_out"]
+        expect(env.build_sources(["precompiled.o", "mod.c", "mod2.ab_in"], [".o", ".ab_out"], cache, {})).to eq ["precompiled.o", "mod.o", "mod2.ab_out"]
       end
     end
 
@@ -310,32 +349,105 @@ module Rscons
             build_op[:vars]["CFLAGS"] += ["-O3", "-DSPECIAL"]
           end
         end
-        env.builders["Object"].stub(:run) do |target, sources, cache, env, vars|
+        allow(env.builders["Object"]).to receive(:run) do |target, sources, cache, env, vars|
-          vars["CFLAGS"].should == []
+          expect(vars["CFLAGS"]).to eq []
         end
         env.run_builder(env.builders["Object"], "build/normal/module.o", ["src/normal/module.c"], "cache", {})
-        env.builders["Object"].stub(:run) do |target, sources, cache, env, vars|
+        allow(env.builders["Object"]).to receive(:run) do |target, sources, cache, env, vars|
-          vars["CFLAGS"].should == ["-O3", "-DSPECIAL"]
+          expect(vars["CFLAGS"]).to eq ["-O3", "-DSPECIAL"]
         end
         env.run_builder(env.builders["Object"], "build/special/module.o", ["src/special/module.c"], "cache", {})
       end
     end
 
+    describe "#shell" do
+      it "executes the given shell command and returns the results" do
+        env = Environment.new
+        expect(env.shell("echo hello").strip).to eq("hello")
+      end
+      it "determines shell flag to be /c when SHELL is specified as 'cmd'" do
+        env = Environment.new
+        env["SHELL"] = "cmd"
+        expect(IO).to receive(:popen).with(["cmd", "/c", "my_cmd"])
+        env.shell("my_cmd")
+      end
+      it "determines shell flag to be -c when SHELL is specified as something else" do
+        env = Environment.new
+        env["SHELL"] = "my_shell"
+        expect(IO).to receive(:popen).with(["my_shell", "-c", "my_cmd"])
+        env.shell("my_cmd")
+      end
+    end
+
+    describe "#parse_flags" do
+      it "executes the shell command and parses the returned flags when the input argument begins with !" do
+        env = Environment.new
+        env["CFLAGS"] = ["-g"]
+        expect(env).to receive(:shell).with("my_command").and_return(%[-arch my_arch -Done=two -include ii -isysroot sr -Iincdir -Llibdir -lmy_lib -mno-cygwin -mwindows -pthread -std=c99 -Wa,'asm,args 1 2' -Wl,linker,"args 1 2" -Wp,cpp,args,1,2 -arbitrary +other_arbitrary some_lib /a/b/c/lib])
+        rv = env.parse_flags("!my_command")
+        expect(rv).to eq({
+          "CCFLAGS" => %w[-arch my_arch -include ii -isysroot sr -mno-cygwin -pthread -arbitrary +other_arbitrary],
+          "LDFLAGS" => %w[-arch my_arch -isysroot sr -mno-cygwin -mwindows -pthread] + ["linker", "args 1 2"] + %w[+other_arbitrary],
+          "CPPPATH" => %w[incdir],
+          "LIBS" => %w[my_lib some_lib /a/b/c/lib],
+          "LIBPATH" => %w[libdir],
+          "CPPDEFINES" => %w[one=two],
+          "CFLAGS" => %w[-std=c99],
+          "ASFLAGS" => ["asm", "args 1 2"],
+          "CPPFLAGS" => %w[cpp args 1 2],
+        })
+        expect(env["CFLAGS"]).to eq(["-g"])
+        expect(env["ASFLAGS"]).to eq([])
+        env.merge_flags(rv)
+        expect(env["CFLAGS"]).to eq(["-g", "-std=c99"])
+        expect(env["ASFLAGS"]).to eq(["asm", "args 1 2"])
+      end
+    end
+
+    describe "#parse_flags!" do
+      it "parses the given build flags and merges them into the Environment" do
+        env = Environment.new
+        env["CFLAGS"] = ["-g"]
+        rv = env.parse_flags!("-I incdir -D my_define -L /a/libdir -l /some/lib")
+        expect(rv).to eq({
+          "CPPPATH" => %w[incdir],
+          "LIBS" => %w[/some/lib],
+          "LIBPATH" => %w[/a/libdir],
+          "CPPDEFINES" => %w[my_define],
+        })
+        expect(env["CPPPATH"]).to eq(%w[incdir])
+        expect(env["LIBS"]).to eq(%w[/some/lib])
+        expect(env["LIBPATH"]).to eq(%w[/a/libdir])
+        expect(env["CPPDEFINES"]).to eq(%w[my_define])
+      end
+    end
+
+    describe "#merge_flags" do
+      it "appends array contents and replaces other variable values" do
+        env = Environment.new
+        env["CPPPATH"] = ["incdir"]
+        env["CSUFFIX"] = ".x"
+        env.merge_flags("CPPPATH" => ["a"], "CSUFFIX" => ".c")
+        expect(env["CPPPATH"]).to eq(%w[incdir a])
+        expect(env["CSUFFIX"]).to eq(".c")
+      end
+    end
+
     describe ".parse_makefile_deps" do
       it 'handles dependencies on one line' do
-        File.should_receive(:read).with('makefile').and_return(<<EOS)
+        expect(File).to receive(:read).with('makefile').and_return(<<EOS)
 module.o: source.cc
 EOS
-        Environment.parse_makefile_deps('makefile', 'module.o').should == ['source.cc']
+        expect(Environment.parse_makefile_deps('makefile', 'module.o')).to eq ['source.cc']
       end
 
       it 'handles dependencies split across many lines' do
-        File.should_receive(:read).with('makefile').and_return(<<EOS)
+        expect(File).to receive(:read).with('makefile').and_return(<<EOS)
 module.o: module.c \\
   module.h \\
   other.h
 EOS
-        Environment.parse_makefile_deps('makefile', 'module.o').should == [
+        expect(Environment.parse_makefile_deps('makefile', 'module.o')).to eq [
           'module.c', 'module.h', 'other.h']
       end
     end

spec/rscons/varset_spec.rb

@@ -1,112 +1,162 @@
 module Rscons
   describe VarSet do
-    describe '.initialize' do
+    describe '#initialize' do
       it "initializes variables from a Hash" do
         v = VarSet.new({"one" => 1, "two" => :two})
-        v["one"].should == 1
+        expect(v["one"]).to eq(1)
-        v["two"].should == :two
+        expect(v["two"]).to eq(:two)
       end
       it "initializes variables from another VarSet" do
         v = VarSet.new({"one" => 1})
         v2 = VarSet.new(v)
-        v2["one"].should == 1
+        expect(v2["one"]).to eq 1
       end
       it "makes a deep copy of the given VarSet" do
         v = VarSet.new({"array" => [1, 2, 3]})
         v2 = VarSet.new(v)
         v["array"] << 4
-        v["array"].should == [1, 2, 3, 4]
+        expect(v["array"]).to eq([1, 2, 3, 4])
-        v2["array"].should == [1, 2, 3]
+        expect(v2["array"]).to eq([1, 2, 3])
       end
     end
 
-    describe :[] do
+    describe "#[]" do
+      it "allows accessing a variable with its verbatim value if type is not specified" do
         v = VarSet.new({"fuz" => "a string", "foo" => 42, "bar" => :baz,
                         "qax" => [3, 6], "qux" => {a: :b}})
-      it "allows accessing a variable with its verbatim value if type is not specified" do
+        expect(v["fuz"]).to eq("a string")
-        v["fuz"].should == "a string"
+        expect(v["foo"]).to eq(42)
-        v["foo"].should == 42
+        expect(v["bar"]).to eq(:baz)
-        v["bar"].should == :baz
+        expect(v["qax"]).to eq([3, 6])
-        v["qax"].should == [3, 6]
+        expect(v["qux"]).to eq({a: :b})
-        v["qux"].should == {a: :b}
       end
     end
 
-    describe :[]= do
+    describe "#[]=" do
       it "allows assigning to variables" do
         v = VarSet.new("CFLAGS" => ["-Wall", "-O3"])
         v["CPPPATH"] = ["one", "two"]
-        v["CFLAGS"].should == ["-Wall", "-O3"]
+        expect(v["CFLAGS"]).to eq(["-Wall", "-O3"])
-        v["CPPPATH"].should == ["one", "two"]
+        expect(v["CPPPATH"]).to eq(["one", "two"])
       end
     end
 
-    describe '.append' do
+    describe "#include?" do
+      it "returns whether the variable is in the VarSet" do
+        v = VarSet.new("CFLAGS" => [], :foo => :bar)
+
+        expect(v.include?("CFLAGS")).to be_truthy
+        expect(v.include?(:CFLAGS)).to be_falsey
+        expect(v.include?(:foo)).to be_truthy
+        expect(v.include?("foo")).to be_falsey
+        expect(v.include?("bar")).to be_falsey
+
+        v2 = v.clone
+        v2.append("bar" => [])
+
+        expect(v2.include?("CFLAGS")).to be_truthy
+        expect(v2.include?(:CFLAGS)).to be_falsey
+        expect(v2.include?(:foo)).to be_truthy
+        expect(v2.include?("foo")).to be_falsey
+        expect(v2.include?("bar")).to be_truthy
+      end
+    end
+
+    describe '#append' do
       it "adds values from a Hash to the VarSet" do
         v = VarSet.new("LDFLAGS" => "-lgcc")
         v.append("LIBS" => "gcc", "LIBPATH" => ["mylibs"])
-        v.vars.keys.should =~ ["LDFLAGS", "LIBS", "LIBPATH"]
+        expect(v["LDFLAGS"]).to eq("-lgcc")
+        expect(v["LIBS"]).to eq("gcc")
+        expect(v["LIBPATH"]).to eq(["mylibs"])
       end
+
       it "adds values from another VarSet to the VarSet" do
         v = VarSet.new("CPPPATH" => ["mydir"])
         v2 = VarSet.new("CFLAGS" => ["-O0"], "CPPPATH" => ["different_dir"])
         v.append(v2)
-        v.vars.keys.should =~ ["CPPPATH", "CFLAGS"]
+        expect(v["CFLAGS"]).to eq(["-O0"])
-        v["CPPPATH"].should == ["different_dir"]
+        expect(v["CPPPATH"]).to eq(["different_dir"])
+      end
+
+      it "does not pick up subsequent variable changes from a given VarSet" do
+        v = VarSet.new("dirs" => ["a"])
+        v2 = VarSet.new
+        v2.append(v)
+        v["dirs"] << "b"
+        expect(v["dirs"]).to eq(["a", "b"])
+        expect(v2["dirs"]).to eq(["a"])
       end
     end
 
-    describe '.merge' do
+    describe '#merge' do
       it "returns a new VarSet merged with the given Hash" do
         v = VarSet.new("foo" => "yoda")
         v2 = v.merge("baz" => "qux")
-        v.vars.keys.should == ["foo"]
+        expect(v["foo"]).to eq("yoda")
-        v2.vars.keys.should =~ ["foo", "baz"]
+        expect(v2["foo"]).to eq("yoda")
+        expect(v2["baz"]).to eq("qux")
       end
+
       it "returns a new VarSet merged with the given VarSet" do
         v = VarSet.new("foo" => ["a", "b"], "bar" => 42)
         v2 = v.merge(VarSet.new("bar" => 33, "baz" => :baz))
         v2["foo"] << "c"
-        v["foo"].should == ["a", "b"]
+        expect(v["foo"]).to eq ["a", "b"]
-        v["bar"].should == 42
+        expect(v["bar"]).to eq 42
-        v2["foo"].should == ["a", "b", "c"]
+        expect(v2["foo"]).to eq ["a", "b", "c"]
-        v2["bar"].should == 33
+        expect(v2["bar"]).to eq 33
+      end
+
+      it "does not pick up subsequent variable changes from a given VarSet" do
+        v = VarSet.new("var" => ["a", "b"], "var2" => ["1", "2"])
+        v["var2"] << "3"
+        v2 = v.clone
+        v["var"] << "c"
+        expect(v["var"]).to eq(["a", "b", "c"])
+        expect(v["var2"]).to eq(["1", "2", "3"])
+        expect(v2["var"]).to eq(["a", "b"])
+        expect(v2["var2"]).to eq(["1", "2", "3"])
       end
     end
 
-    describe '.expand_varref' do
+    describe '#expand_varref' do
       v = VarSet.new("CFLAGS" => ["-Wall", "-O2"],
                      "CC" => "gcc",
                      "CPPPATH" => ["dir1", "dir2"],
                      "compiler" => "${CC}",
-                     "cmd" => ["${CC}", "-c", "${CFLAGS}", "-I${CPPPATH}"])
+                     "cmd" => ["${CC}", "-c", "${CFLAGS}", "-I${CPPPATH}"],
+                     "hash" => {})
       it "expands to the string itself if the string is not a variable reference" do
-        v.expand_varref("CC").should == "CC"
+        expect(v.expand_varref("CC")).to eq("CC")
-        v.expand_varref("CPPPATH").should == "CPPPATH"
+        expect(v.expand_varref("CPPPATH")).to eq("CPPPATH")
-        v.expand_varref("str").should == "str"
+        expect(v.expand_varref("str")).to eq("str")
       end
       it "expands a single variable reference beginning with a '$'" do
-        v.expand_varref("${CC}").should == "gcc"
+        expect(v.expand_varref("${CC}")).to eq("gcc")
-        v.expand_varref("${CPPPATH}").should == ["dir1", "dir2"]
+        expect(v.expand_varref("${CPPPATH}")).to eq(["dir1", "dir2"])
       end
       it "expands a single variable reference in ${arr} notation" do
-        v.expand_varref("prefix${CFLAGS}suffix").should == ["prefix-Wallsuffix", "prefix-O2suffix"]
+        expect(v.expand_varref("prefix${CFLAGS}suffix")).to eq(["prefix-Wallsuffix", "prefix-O2suffix"])
-        v.expand_varref(v["cmd"]).should == ["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"]
+        expect(v.expand_varref(v["cmd"])).to eq(["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"])
       end
       it "expands a variable reference recursively" do
-        v.expand_varref("${compiler}").should == "gcc"
+        expect(v.expand_varref("${compiler}")).to eq("gcc")
-        v.expand_varref("${cmd}").should == ["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"]
+        expect(v.expand_varref("${cmd}")).to eq(["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"])
       end
       it "resolves multiple variable references in one element by enumerating all combinations" do
-        v.expand_varref("cflag: ${CFLAGS}, cpppath: ${CPPPATH}, compiler: ${compiler}").should == [
+        expect(v.expand_varref("cflag: ${CFLAGS}, cpppath: ${CPPPATH}, compiler: ${compiler}")).to eq([
           "cflag: -Wall, cpppath: dir1, compiler: gcc",
           "cflag: -O2, cpppath: dir1, compiler: gcc",
           "cflag: -Wall, cpppath: dir2, compiler: gcc",
           "cflag: -O2, cpppath: dir2, compiler: gcc",
-        ]
+        ])
       end
-      it "raises an error when a variable reference refers to a non-existent variable" do
+      it "returns an empty string when a variable reference refers to a non-existent variable" do
-        expect { v.expand_varref("${not_here}") }.to raise_error /I do not know how to expand a variable reference to a NilClass/
+        expect(v.expand_varref("${not_here}")).to eq("")
+      end
+      it "raises an error when a variable reference refers to an unhandled type" do
+        expect { v.expand_varref("${hash}") }.to raise_error /I do not know how to expand a variable reference to a Hash/
       end
     end
   end

spec/rscons_spec.rb

@@ -2,25 +2,114 @@ describe Rscons do
   describe ".clean" do
     it "removes all build targets and created directories" do
       cache = "cache"
-      Rscons::Cache.should_receive(:new).and_return(cache)
+      expect(Rscons::Cache).to receive(:instance).and_return(cache)
-      cache.should_receive(:targets).and_return(["build/a.out", "build/main.o"])
+      expect(cache).to receive(:targets).and_return(["build/a.out", "build/main.o"])
-      FileUtils.should_receive(:rm_f).with("build/a.out")
+      expect(FileUtils).to receive(:rm_f).with("build/a.out")
-      FileUtils.should_receive(:rm_f).with("build/main.o")
+      expect(FileUtils).to receive(:rm_f).with("build/main.o")
-      cache.should_receive(:directories).and_return(["build/one", "build/one/two", "build", "other"])
+      expect(cache).to receive(:directories).and_return(["build/one", "build/one/two", "build", "other"])
-      File.should_receive(:directory?).with("build/one/two").and_return(true)
+      expect(File).to receive(:directory?).with("build/one/two").and_return(true)
-      Dir.should_receive(:entries).with("build/one/two").and_return([".", ".."])
+      expect(Dir).to receive(:entries).with("build/one/two").and_return([".", ".."])
-      Dir.should_receive(:rmdir).with("build/one/two")
+      expect(Dir).to receive(:rmdir).with("build/one/two")
-      File.should_receive(:directory?).with("build/one").and_return(true)
+      expect(File).to receive(:directory?).with("build/one").and_return(true)
-      Dir.should_receive(:entries).with("build/one").and_return([".", ".."])
+      expect(Dir).to receive(:entries).with("build/one").and_return([".", ".."])
-      Dir.should_receive(:rmdir).with("build/one")
+      expect(Dir).to receive(:rmdir).with("build/one")
-      File.should_receive(:directory?).with("build").and_return(true)
+      expect(File).to receive(:directory?).with("build").and_return(true)
-      Dir.should_receive(:entries).with("build").and_return([".", ".."])
+      expect(Dir).to receive(:entries).with("build").and_return([".", ".."])
-      Dir.should_receive(:rmdir).with("build")
+      expect(Dir).to receive(:rmdir).with("build")
-      File.should_receive(:directory?).with("other").and_return(true)
+      expect(File).to receive(:directory?).with("other").and_return(true)
-      Dir.should_receive(:entries).with("other").and_return([".", "..", "other.file"])
+      expect(Dir).to receive(:entries).with("other").and_return([".", "..", "other.file"])
-      Rscons::Cache.should_receive(:clear)
+      expect(cache).to receive(:clear)
 
       Rscons.clean
     end
   end
+
+  describe ".get_system_shell" do
+    before(:each) do
+      Rscons.class_variable_set(:@@shell, nil)
+    end
+
+    after(:each) do
+      Rscons.class_variable_set(:@@shell, nil)
+    end
+
+    it "uses the SHELL environment variable if it tests successfully" do
+      my_ENV = {"SHELL" => "my_shell"}
+      allow(ENV).to receive(:[]) {|*args| my_ENV[*args]}
+      io = StringIO.new("success\n")
+      expect(IO).to receive(:popen).with(["my_shell", "-c", "echo success"]).and_yield(io)
+      expect(Rscons.get_system_shell).to eq(["my_shell", "-c"])
+    end
+
+    it "uses sh -c on a mingw platform if it tests successfully" do
+      my_ENV = {"SHELL" => nil}
+      allow(ENV).to receive(:[]) {|*args| my_ENV[*args]}
+      io = StringIO.new("success\n")
+      expect(IO).to receive(:popen).with(["sh", "-c", "echo success"]).and_yield(io)
+      expect(Object).to receive(:const_get).with("RUBY_PLATFORM").and_return("x86-mingw")
+      expect(Rscons.get_system_shell).to eq(["sh", "-c"])
+    end
+
+    it "uses cmd /c on a mingw platform if sh -c does not test successfully" do
+      my_ENV = {"SHELL" => nil}
+      allow(ENV).to receive(:[]) {|*args| my_ENV[*args]}
+      io = StringIO.new("success\n")
+      expect(IO).to receive(:popen).with(["sh", "-c", "echo success"]).and_raise "ENOENT"
+      expect(Object).to receive(:const_get).with("RUBY_PLATFORM").and_return("x86-mingw")
+      expect(Rscons.get_system_shell).to eq(["cmd", "/c"])
+    end
+
+    it "uses sh -c on a non-mingw platform if SHELL is not specified" do
+      my_ENV = {"SHELL" => nil}
+      allow(ENV).to receive(:[]) {|*args| my_ENV[*args]}
+      expect(Object).to receive(:const_get).with("RUBY_PLATFORM").and_return("x86-linux")
+      expect(Rscons.get_system_shell).to eq(["sh", "-c"])
+    end
+  end
+
+  context "command executer" do
+    describe ".command_executer" do
+      before(:each) do
+        Rscons.class_variable_set(:@@command_executer, nil)
+      end
+
+      after(:each) do
+        Rscons.class_variable_set(:@@command_executer, nil)
+      end
+
+      it "returns ['env'] if mingw platform in MSYS and 'env' works" do
+        expect(Object).to receive(:const_get).and_return("x86-mingw")
+        expect(ENV).to receive(:keys).and_return(["MSYSCON"])
+        io = StringIO.new("success\n")
+        expect(IO).to receive(:popen).with(["env", "echo", "success"]).and_yield(io)
+        expect(Rscons.command_executer).to eq(["env"])
+      end
+
+      it "returns [] if mingw platform in MSYS and 'env' does not work" do
+        expect(Object).to receive(:const_get).and_return("x86-mingw")
+        expect(ENV).to receive(:keys).and_return(["MSYSCON"])
+        expect(IO).to receive(:popen).with(["env", "echo", "success"]).and_raise "ENOENT"
+        expect(Rscons.command_executer).to eq([])
+      end
+
+      it "returns [] if mingw platform not in MSYS" do
+        expect(Object).to receive(:const_get).and_return("x86-mingw")
+        expect(ENV).to receive(:keys).and_return(["COMSPEC"])
+        expect(Rscons.command_executer).to eq([])
+      end
+
+      it "returns [] if not mingw platform" do
+        expect(Object).to receive(:const_get).and_return("x86-linux")
+        expect(Rscons.command_executer).to eq([])
+      end
+    end
+
+    describe ".command_executer=" do
+      it "overrides the value of @@command_executer" do
+        Rscons.class_variable_set(:@@command_executer, ["env"])
+        Rscons.command_executer = []
+        expect(Rscons.class_variable_get(:@@command_executer)).to eq([])
+      end
+    end
+  end
 end