v1.7.0

.gitignore

@@ -1,18 +1,6 @@
-*.gem
+/.yardoc/
-*.rbc
+/_yardoc/
-.bundle
+/coverage/
-.config
+/doc/
-.yardoc
+/pkg/
-Gemfile.lock
+/build_test_run/
-InstalledFiles
-_yardoc
-coverage
-doc/
-lib/bundler/man
-pkg
-rdoc
-spec/reports
-test/tmp
-test/version_tmp
-tmp
-build_test_run

Gemfile.lock

@@ -0,0 +1,45 @@
+PATH
+  remote: .
+  specs:
+    rscons (1.7.0)
+      json (~> 1.0)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.2.5)
+    docile (1.1.5)
+    json (1.8.1)
+    multi_json (1.10.1)
+    rake (10.3.2)
+    redcarpet (3.1.2)
+    rspec (3.0.0)
+      rspec-core (~> 3.0.0)
+      rspec-expectations (~> 3.0.0)
+      rspec-mocks (~> 3.0.0)
+    rspec-core (3.0.1)
+      rspec-support (~> 3.0.0)
+    rspec-expectations (3.0.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.0.0)
+    rspec-mocks (3.0.1)
+      rspec-support (~> 3.0.0)
+    rspec-support (3.0.0)
+    simplecov (0.8.2)
+      docile (~> 1.1.0)
+      multi_json
+      simplecov-html (~> 0.8.0)
+    simplecov-html (0.8.0)
+    yard (0.8.7.4)
+
+PLATFORMS
+  ruby
+  x86-mingw32
+
+DEPENDENCIES
+  rake
+  redcarpet
+  rscons!
+  rspec
+  simplecov
+  yard

README.md

@@ -173,6 +173,9 @@ Each build hook block will be invoked for every build operation, so the block
 should test the target or sources if its action should only apply to some
 subset of build targets or source files.
 
+Build hooks can alter construction variable values for a particular build
+operation. Build hooks can also register new build targets.
+
 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
@@ -317,6 +320,19 @@ cloned_env["CPPPATH"] << "three"
 
 `base_env["CPPPATH"]` will not include "three".
 
+#### Build Hooks
+
+Environments can have build hooks which are added with `env.add_build_hook()`.
+Build hooks are invoked immediately before a builder executes.
+Build hooks can modify the construction variables in use for the build
+operation.
+They can also register new build targets.
+
+Environments can also have post-build hooks added with `env.add_post_build_hook()`.
+Post-build hooks are only invoked if the build operation was a success.
+Post-build hooks can invoke commands using the newly-built files, or register
+new build targets.
+
 ### Construction Variable Naming
 
 * uppercase strings - the default construction variables that Rscons uses
@@ -329,6 +345,35 @@ http://rubydoc.info/github/holtrop/rscons/frames.
 
 ## Release Notes
 
+### v1.7.0
+
+- allow build hooks to register new build targets
+- add post-build hooks (register with Environment#add_post_build_hook)
+- clear all build targets after processing an Environment
+- allow trailing slashes in arguments to Environment#build_dir
+
+### v1.6.1
+
+- add DEPFILESUFFIX construction variable to override dependency file suffix
+- fix Environment#depends to expand its arguments for construction variables
+
+### v1.6.0
+
+- support lambdas as construction variable values
+
+### v1.5.0
+
+- add "json" as a runtime dependency
+- update construction variables to match SCons more closely
+  - add CPPDEFPREFIX, INCPREFIX, CPPDEFINES, CCFLAGS, LIBDIRPREFIX, and LIBLINKPREFIX
+- add Environment#shell
+- add Environment#parse_flags, #parse_flags!, #merge_flags
+- unbuffer $stdout by default
+- add PROGSUFFIX construction variable (defaults to .exe on MinGW/Cygwin)
+- add Rscons::BuildTarget and Builder#create_build_target
+- update specs to RSpec 3.x and fix to run on MinGW/Cygwin/Linux
+- add YARD documentation to get to 100% coverage
+
 ### v1.4.3
 
 - fix builders properly using construction variable overrides

Rakefile.rb

@@ -8,6 +8,10 @@ end
 require "bundler/gem_tasks"
 require "rspec/core/rake_task"
 require "yard"
+require "rake/clean"
+
+CLEAN.include %w[build_test_run .yardoc doc coverage]
+CLOBBER.include %w[pkg]
 
 RSpec::Core::RakeTask.new(:spec)
 
@@ -16,11 +20,3 @@ YARD::Rake::YardocTask.new do |yard|
 end
 
 task :default => :spec
-
-task :clean do
-  FileUtils.rm_rf(["build_test_run", "doc", "coverage"])
-end
-
-task :clobber => :clean do
-  FileUtils.rm_rf(["pkg"])
-end

lib/rscons/builders/object.rb

@@ -19,6 +19,7 @@ module Rscons
       def default_variables(env)
         {
           'OBJSUFFIX' => '.o',
+          'DEPFILESUFFIX' => '.mf',
 
           'CPPDEFPREFIX' => '-D',
           'INCPREFIX' => '-I',
@@ -87,7 +88,7 @@ module Rscons
         vars = vars.merge({
           '_TARGET' => target,
           '_SOURCES' => sources,
-          '_DEPFILE' => Rscons.set_suffix(target, '.mf'),
+          '_DEPFILE' => Rscons.set_suffix(target, env.expand_varref("${DEPFILESUFFIX}", vars)),
         })
         com_prefix = KNOWN_SUFFIXES.find do |compiler, suffix_var|
           sources.first.end_with?(*env.expand_varref("${#{suffix_var}}"))

lib/rscons/environment.rb

@@ -7,7 +7,7 @@ module Rscons
   # contains a collection of construction variables, options, builders, and
   # rules for building targets.
   class Environment
-    # @return [Hash] Set of \{"builder_name" => builder_object} pairs.
+    # @return [Hash] Set of !{"builder_name" => builder_object} pairs.
     attr_reader :builders
 
     # :command, :short, or :off
@@ -42,7 +42,7 @@ module Rscons
       @user_deps = {}
       @builders = {}
       @build_dirs = []
-      @build_hooks = []
+      @build_hooks = {pre: [], post: []}
       unless options[:exclude_builders]
         DEFAULT_BUILDERS.each do |builder_class_name|
           builder_class = Builders.const_get(builder_class_name)
@@ -103,9 +103,12 @@ module Rscons
         end
       end
       if clone.include?(:build_hooks)
-        @build_hooks.each do |build_hook_block|
+        @build_hooks[:pre].each do |build_hook_block|
           env.add_build_hook(&build_hook_block)
         end
+        @build_hooks[:post].each do |build_hook_block|
+          env.add_post_build_hook(&build_hook_block)
+        end
       end
 
       if block_given?
@@ -132,6 +135,12 @@ module Rscons
 
     # Add a build hook to the Environment.
     #
+    # Build hooks are Ruby blocks which are invoked immediately before a
+    # build operation takes place. Build hooks have an opportunity to modify
+    # the construction variables in use for the build operation based on the
+    # builder in use, target file name, or sources. Build hooks can also
+    # register new build targets.
+    #
     # @yield [build_op]
     #   Invoke the given block with the current build operation.
     # @yieldparam build_op [Hash]
@@ -144,19 +153,45 @@ module Rscons
     #
     # @return [void]
     def add_build_hook(&block)
-      @build_hooks << block
+      @build_hooks[:pre] << block
+    end
+
+    # Add a post build hook to the Environment.
+    #
+    # Post-build hooks are Ruby blocks which are invoked immediately after a
+    # build operation takes place. Post-build hooks are only invoked if the
+    # build operation succeeded. Post-build hooks can register new build
+    # targets.
+    #
+    # @since 1.7.0
+    #
+    # @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_post_build_hook(&block)
+      @build_hooks[:post] << 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 src_dir [String, Regexp] 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)
+      if src_dir.is_a?(String)
+        src_dir = src_dir.gsub("\\", "/").sub(%r{/*$}, "")
+      end
       @build_dirs << [src_dir, obj_dir]
     end
 
@@ -216,23 +251,25 @@ module Rscons
     #
     # @return [void]
     def process
-      unless @targets.empty?
+      expand_paths!
-        expand_paths!
+      while @targets.size > 0
+        targets = @targets
+        @targets = {}
         cache = Cache.instance
         cache.clear_checksum_cache!
         targets_processed = {}
         process_target = proc do |target|
           targets_processed[target] ||= begin
-            @targets[target][:sources].each do |src|
+            targets[target][:sources].each do |src|
-              if @targets.include?(src) and not targets_processed.include?(src)
+              if targets.include?(src) and not targets_processed.include?(src)
                 process_target.call(src)
               end
             end
-            result = run_builder(@targets[target][:builder],
+            result = run_builder(targets[target][:builder],
                                  target,
-                                 @targets[target][:sources],
+                                 targets[target][:sources],
                                  cache,
-                                 @targets[target][:vars] || {})
+                                 targets[target][:vars] || {})
             unless result
               raise BuildError.new("Failed to build #{target}")
             end
@@ -240,7 +277,7 @@ module Rscons
           end
         end
         begin
-          @targets.each do |target, target_params|
+          targets.each do |target, target_params|
             process_target.call(target)
           end
         ensure
@@ -263,11 +300,13 @@ module Rscons
     #
     # @return [Array, String] Expansion of the variable reference.
     def expand_varref(varref, extra_vars = nil)
-      if extra_vars.nil?
+      vars = if extra_vars.nil?
-        @varset
+               @varset
-      else
+             else
-        @varset.merge(extra_vars)
+               @varset.merge(extra_vars)
-      end.expand_varref(varref)
+             end
+      lambda_args = [env: self, vars: vars]
+      vars.expand_varref(varref, lambda_args)
     end
     alias_method :build_command, :expand_varref
 
@@ -349,7 +388,8 @@ module Rscons
     #
     # @return [void]
     def depends(target, *user_deps)
-      target = target.to_s
+      target = expand_varref(target.to_s)
+      user_deps = user_deps.map {|ud| expand_varref(ud)}
       @user_deps[target] ||= []
       @user_deps[target] = (@user_deps[target] + user_deps).uniq
     end
@@ -407,17 +447,22 @@ module Rscons
     # @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|
+      call_build_hooks = lambda do |sec|
-        build_operation = {
+        @build_hooks[sec].each do |build_hook_block|
-          builder: builder,
+          build_operation = {
-          target: target,
+            builder: builder,
-          sources: sources,
+            target: target,
-          vars: vars,
+            sources: sources,
-          env: self,
+            vars: vars,
-        }
+            env: self,
-        build_hook_block.call(build_operation)
+          }
+          build_hook_block.call(build_operation)
+        end
       end
-      builder.run(target, sources, cache, self, vars)
+      call_build_hooks[:pre]
+      rv = builder.run(target, sources, cache, self, vars)
+      call_build_hooks[:post] if rv
+      rv
     end
 
     # Expand a path to be relative to the Environment's build root.

lib/rscons/varset.rb

@@ -83,32 +83,41 @@ module Rscons
     end
     alias_method :clone, :merge
 
-    # Replace "$\{var}" variable references in varref with the expanded
+    # Replace "$!{var}" variable references in varref with the expanded
     # variables' values, recursively.
     #
-    # @param varref [String, Array] Value containing references to variables.
+    # @param varref [nil, String, Array, Proc]
+    #   Value containing references to variables.
+    # @param lambda_args [Array]
+    #   Arguments to pass to any lambda variable values to be expanded.
     #
-    # @return [String, Array]
+    # @return [nil, String, Array]
-    #   Expanded value with "$\{var}" variable references replaced.
+    #   Expanded value with "$!{var}" variable references replaced.
-    def expand_varref(varref)
+    def expand_varref(varref, lambda_args)
-      if varref.is_a?(Array)
+      if varref.is_a?(String)
-        varref.map do |ent|
-          expand_varref(ent)
-        end.flatten
-      else
         if varref =~ /^(.*)\$\{([^}]+)\}(.*)$/
           prefix, varname, suffix = $1, $2, $3
-          varval = expand_varref(self[varname])
+          varval = expand_varref(self[varname], lambda_args)
           if varval.is_a?(String) or varval.nil?
-            expand_varref("#{prefix}#{varval}#{suffix}")
+            expand_varref("#{prefix}#{varval}#{suffix}", lambda_args)
           elsif varval.is_a?(Array)
-            varval.map {|vv| expand_varref("#{prefix}#{vv}#{suffix}")}.flatten
+            varval.map {|vv| expand_varref("#{prefix}#{vv}#{suffix}", lambda_args)}.flatten
           else
             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
+      elsif varref.is_a?(Array)
+        varref.map do |ent|
+          expand_varref(ent, lambda_args)
+        end.flatten
+      elsif varref.is_a?(Proc)
+        expand_varref(varref[*lambda_args], lambda_args)
+      elsif varref.nil?
+        nil
+      else
+        raise "Unknown varref type: #{varref.class} (#{varref.inspect})"
       end
     end
 

lib/rscons/version.rb

@@ -1,4 +1,4 @@
 module Rscons
   # gem version
-  VERSION = "1.5.0"
+  VERSION = "1.7.0"
 end

spec/build_tests_spec.rb

@@ -10,6 +10,7 @@ class Dir
 end
 
 describe Rscons do
+
   BUILD_TEST_RUN_DIR = "build_test_run"
 
   def rm_rf(dir)
@@ -120,34 +121,43 @@ describe Rscons do
 
   it 'rebuilds a C module when a header it depends on changes' do
     test_dir('header')
-    env = Rscons::Environment.new do |env|
+    make_env = lambda do
-      env.Program('header', Dir['*.c'])
+      Rscons::Environment.new do |env|
+        env.Program('header', Dir['*.c'])
+      end
     end
+    make_env[]
     expect(`./header`).to eq "The value is 2\n"
     file_sub('header.h') {|line| line.sub(/2/, '5')}
-    env.process
+    make_env[]
     expect(`./header`).to eq "The value is 5\n"
   end
 
   it 'does not rebuild a C module when its dependencies have not changed' do
     test_dir('header')
-    env = Rscons::Environment.new do |env|
+    make_env = lambda do
-      env.Program('header', Dir['*.c'])
+      Rscons::Environment.new do |env|
+        env.Program('header', Dir['*.c'])
+      end
     end
+    env = make_env[]
     expect(`./header`).to eq "The value is 2\n"
     expect(lines).to eq [
       'CC header.o',
       "LD header#{env["PROGSUFFIX"]}",
     ]
-    env.process
+    make_env[]
     expect(lines).to eq []
   end
 
   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|
+    make_env = lambda do
-      env.Program('header', Dir['*.c'])
+      Rscons::Environment.new do |env|
+        env.Program('header', Dir['*.c'])
+      end
     end
+    env = make_env[]
     expect(`./header`).to eq "The value is 2\n"
     expect(lines).to eq [
       'CC header.o',
@@ -155,7 +165,7 @@ describe Rscons do
     ]
     sleep 0.05
     file_sub('header.c') {|line| line}
-    env.process
+    make_env[]
     expect(lines).to eq []
   end
 
@@ -187,6 +197,19 @@ describe Rscons do
     expect(File.exists?('build_two/two.o')).to be_truthy
   end
 
+  it "supports trailing slashes at the end of build_dir sources and destinations" do
+    test_dir("build_dir")
+    Rscons::Environment.new do |env|
+      env.append("CPPPATH" => Dir["src/**/*/"])
+      env.build_dir("src/one/", "build_one/")
+      env.build_dir("src/two", "build_two")
+      env.Program("build_dir", Dir["src/**/*.c"])
+    end
+    expect(`./build_dir`).to eq "Hello from two()\n"
+    expect(File.exists?("build_one/one.o")).to be_truthy
+    expect(File.exists?("build_two/two.o")).to be_truthy
+  end
+
   it 'uses build directories before build root' do
     test_dir('build_dir')
     env = Rscons::Environment.new do |env|
@@ -303,11 +326,14 @@ EOF
       end
     end
 
-    env = Rscons::Environment.new do |env|
+    make_env = lambda do
-      env.add_builder(CHGen.new)
+      Rscons::Environment.new do |env|
-      env.CHGen("inc.c", ["program.c"])
+        env.add_builder(CHGen.new)
-      env.Program("program", Dir["*.c"] + ["inc.c"])
+        env.CHGen("inc.c", ["program.c"])
+        env.Program("program", %w[program.c inc.c])
+      end
     end
+    env = make_env[]
 
     expect(lines).to eq ["CHGen inc.c", "CC program.o", "CC inc.o", "LD program#{env["PROGSUFFIX"]}"]
     expect(File.exists?("inc.c")).to be_truthy
@@ -315,7 +341,7 @@ EOF
     expect(`./program`).to eq "The value is 42\n"
 
     File.open("inc.c", "w") {|fh| fh.puts "int THE_VALUE = 33;"}
-    env.process
+    make_env[]
     expect(lines).to eq ["CHGen inc.c"]
     expect(`./program`).to eq "The value is 42\n"
   end
@@ -347,12 +373,16 @@ EOF
   it 'allows cloning all attributes of an Environment object' do
     test_dir('clone_env')
 
+    built_targets = []
     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.add_post_build_hook do |build_op|
+        built_targets << build_op[:target]
+      end
       env.Program('program', Dir['src/*.c'])
     end
 
@@ -365,6 +395,12 @@ EOF
       %Q{gcc -o program#{env1["PROGSUFFIX"]} build/program.o},
       %Q{gcc -o program2#{env2["PROGSUFFIX"]} build/program.o},
     ]
+    expect(built_targets).to eq([
+      "build/program.o",
+      "program#{env1['PROGSUFFIX']}",
+      "build/program.o",
+      "program2#{env1['PROGSUFFIX']}",
+    ])
   end
 
   it 'builds a C++ program with one source file' do
@@ -543,4 +579,125 @@ EOF
     expect(File.exists?('inc.h')).to be_truthy
     expect(`./program`).to eq "The value is 678\n"
   end
+
+  it "supports lambdas as construction variable values" do
+    env = Rscons::Environment.new do |env|
+      env["prefix"] = "-H"
+      env["suffix"] = "xyz"
+      env[:cfg] = {val: 44}
+      env["computed"] = lambda do |args|
+        "#{args[:env]['prefix']}#{args[:env][:cfg][:val]}#{args[:env]['suffix']}"
+      end
+      env["lambda_recurse"] = lambda do |args|
+        "${prefix}ello"
+      end
+    end
+    e2 = env.clone
+    e2[:cfg][:val] = 38
+    expect(env.expand_varref("${computed}")).to eq("-H44xyz")
+    expect(e2.expand_varref("${computed}")).to eq("-H38xyz")
+    expect(env.expand_varref("${lambda_recurse}")).to eq("-Hello")
+  end
+
+  it "supports registering build targets from within a build hook" do
+    test_dir("simple")
+    Rscons::Environment.new do |env|
+      env.Program("simple", Dir["*.c"])
+      env.add_build_hook do |build_op|
+        if build_op[:target].end_with?(".o")
+          env.Disassemble("#{build_op[:target]}.txt", build_op[:target])
+        end
+      end
+    end
+    expect(File.exists?("simple.o")).to be_truthy
+    expect(File.exists?("simple.o.txt")).to be_truthy
+    expect(`./simple`).to eq "This is a simple C program\n"
+  end
+
+  it "supports post-build hooks" do
+    test_dir("simple")
+    built_targets = []
+    env = Rscons::Environment.new do |env|
+      env.Program("simple", Dir["*.c"])
+      env.add_post_build_hook do |build_op|
+        built_targets << build_op[:target]
+        expect(File.exists?(build_op[:target])).to be_truthy
+      end
+    end
+    expect(File.exists?("simple.o")).to be_truthy
+    expect(`./simple`).to eq "This is a simple C program\n"
+    expect(built_targets).to eq ["simple.o", "simple#{env["PROGSUFFIX"]}"]
+  end
+
+  it "supports multiple values for CXXSUFFIX" do
+    test_dir("simple_cc")
+    File.open("other.cccc", "w") {|fh| fh.puts}
+    Rscons::Environment.new do |env|
+      env["CXXSUFFIX"] = %w[.cccc .cc]
+      env["CXXFLAGS"] += %w[-x c++]
+      env.Program("simple", Dir["*.cc"] + ["other.cccc"])
+    end
+    expect(File.exists?("simple.o")).to be_truthy
+    expect(File.exists?("other.o")).to be_truthy
+    expect(`./simple`).to eq "This is a simple C++ program\n"
+  end
+
+  it "supports multiple values for CSUFFIX" do
+    test_dir("build_dir")
+    FileUtils.mv("src/one/one.c", "src/one/one.yargh")
+    Rscons::Environment.new do |env|
+      env["CSUFFIX"] = %w[.yargh .c]
+      env["CFLAGS"] += %w[-x c]
+      env["CPPPATH"] += Dir["src/**/"]
+      env.Program("build_dir", Dir["src/**/*.{c,yargh}"])
+    end
+    expect(File.exists?("src/one/one.o")).to be_truthy
+    expect(File.exists?("src/two/two.o")).to be_truthy
+    expect(`./build_dir`).to eq "Hello from two()\n"
+  end
+
+  it "supports multiple values for OBJSUFFIX" do
+    test_dir("two_sources")
+    env = Rscons::Environment.new() do |env|
+      env["OBJSUFFIX"] = %w[.oooo .ooo]
+      env.Object("one.oooo", "one.c", "CPPFLAGS" => ["-DONE"])
+      env.Object("two.ooo", "two.c")
+      env.Program("two_sources", %w[one.oooo two.ooo])
+    end
+    expect(File.exists?("two_sources#{env["PROGSUFFIX"]}")).to be_truthy
+    expect(`./two_sources`).to eq "This is a C program with two sources.\n"
+  end
+
+  it "supports multiple values for LIBSUFFIX" do
+    test_dir("two_sources")
+    env = Rscons::Environment.new() do |env|
+      env["LIBSUFFIX"] = %w[.aaaa .aaa]
+      env.Library("one.aaaa", "one.c", "CPPFLAGS" => ["-DONE"])
+      env.Library("two.aaa", "two.c")
+      env.Program("two_sources", %w[one.aaaa two.aaa])
+    end
+    expect(File.exists?("two_sources#{env["PROGSUFFIX"]}")).to be_truthy
+    expect(`./two_sources`).to eq "This is a C program with two sources.\n"
+  end
+
+  it "supports multiple values for ASSUFFIX" do
+    test_dir("two_sources")
+    env = Rscons::Environment.new() do |env|
+      env["ASSUFFIX"] = %w[.ssss .sss]
+      env["CFLAGS"] += %w[-S]
+      env.Object("one.ssss", "one.c", "CPPFLAGS" => ["-DONE"])
+      env.Object("two.sss", "two.c")
+      env.Program("two_sources", %w[one.ssss two.sss], "ASFLAGS" => env["ASFLAGS"] + %w[-x assembler])
+    end
+    expect(lines).to eq([
+      "CC one.ssss",
+      "CC two.sss",
+      "AS one.o",
+      "AS two.o",
+      "LD two_sources#{env["PROGSUFFIX"]}",
+    ])
+    expect(File.exists?("two_sources#{env["PROGSUFFIX"]}")).to be_truthy
+    expect(`./two_sources`).to eq "This is a C program with two sources.\n"
+  end
+
 end

spec/rscons/builders/object_spec.rb

@@ -2,19 +2,31 @@ module Rscons
   module Builders
     describe Object do
       let(:env) {Environment.new}
+      let(:cache) {double(Cache)}
       subject {Object.new}
 
       it "supports overriding CCCMD construction variable" do
-        cache = "cache"
+        expect(cache).to receive(:up_to_date?).and_return(false)
-        allow(cache).to receive(:up_to_date?) { false }
+        expect(cache).to receive(:mkdir_p)
-        allow(cache).to receive(:mkdir_p) { }
+        expect(FileUtils).to receive(:rm_f)
-        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)
+        expect(File).to receive(:exists?).and_return(false)
+        expect(cache).to receive(:register_build)
+
         subject.run("mod.o", ["mod.c"], cache, env, "CCCMD" => ["llc", "${_SOURCES}"])
       end
 
+      it "supports overriding DEPFILESUFFIX construction variable" do
+        expect(cache).to receive(:up_to_date?).and_return(false)
+        expect(cache).to receive(:mkdir_p)
+        expect(FileUtils).to receive(:rm_f)
+        expect(env).to receive(:execute).with(anything, %w[gcc -c -o f.o -MMD -MF f.d in.c]).and_return(true)
+        expect(File).to receive(:exists?).with("f.d").and_return(false)
+        expect(cache).to receive(:register_build)
+
+        subject.run("f.o", ["in.c"], cache, env, "DEPFILESUFFIX" => ".d")
+      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

spec/rscons/environment_spec.rb

@@ -247,7 +247,7 @@ module Rscons
         env["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("${foo}")}.to raise_error /expand.a.variable.reference/
+        expect {env.expand_varref("${foo}")}.to raise_error /Unknown.varref.type/
         expect(env.expand_varref("${specialflag}")).to eq "-z"
         expect(env.expand_varref("${path}")).to eq ["dir1", "dir2"]
       end
@@ -322,6 +322,13 @@ module Rscons
         env.depends("foo", "bar", "baz")
         expect(env.instance_variable_get(:@user_deps)).to eq({"foo" => ["bar", "baz"]})
       end
+      it "expands arguments for construction variable references" do
+        env = Environment.new
+        env["foo"] = "foo.exe"
+        env["bar"] = "bar.c"
+        env.depends("${foo}", "${bar}", "a.h")
+        expect(env.instance_variable_get(:@user_deps)).to eq({"foo.exe" => ["bar.c", "a.h"]})
+      end
     end
 
     describe "#build_sources" do

spec/rscons/varset_spec.rb

@@ -126,26 +126,26 @@ module Rscons
                      "CPPPATH" => ["dir1", "dir2"],
                      "compiler" => "${CC}",
                      "cmd" => ["${CC}", "-c", "${CFLAGS}", "-I${CPPPATH}"],
-                     "hash" => {})
+                     "lambda" => lambda {|args| "#{args[:v]}--12"})
       it "expands to the string itself if the string is not a variable reference" do
-        expect(v.expand_varref("CC")).to eq("CC")
+        expect(v.expand_varref("CC", :lambda_args)).to eq("CC")
-        expect(v.expand_varref("CPPPATH")).to eq("CPPPATH")
+        expect(v.expand_varref("CPPPATH", :lambda_args)).to eq("CPPPATH")
-        expect(v.expand_varref("str")).to eq("str")
+        expect(v.expand_varref("str", :lambda_args)).to eq("str")
       end
       it "expands a single variable reference beginning with a '$'" do
-        expect(v.expand_varref("${CC}")).to eq("gcc")
+        expect(v.expand_varref("${CC}", :lambda_args)).to eq("gcc")
-        expect(v.expand_varref("${CPPPATH}")).to eq(["dir1", "dir2"])
+        expect(v.expand_varref("${CPPPATH}", :lambda_args)).to eq(["dir1", "dir2"])
       end
       it "expands a single variable reference in ${arr} notation" do
-        expect(v.expand_varref("prefix${CFLAGS}suffix")).to eq(["prefix-Wallsuffix", "prefix-O2suffix"])
+        expect(v.expand_varref("prefix${CFLAGS}suffix", :lambda_args)).to eq(["prefix-Wallsuffix", "prefix-O2suffix"])
-        expect(v.expand_varref(v["cmd"])).to eq(["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"])
+        expect(v.expand_varref(v["cmd"], :lambda_args)).to eq(["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"])
       end
       it "expands a variable reference recursively" do
-        expect(v.expand_varref("${compiler}")).to eq("gcc")
+        expect(v.expand_varref("${compiler}", :lambda_args)).to eq("gcc")
-        expect(v.expand_varref("${cmd}")).to eq(["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"])
+        expect(v.expand_varref("${cmd}", :lambda_args)).to eq(["gcc", "-c", "-Wall", "-O2", "-Idir1", "-Idir2"])
       end
       it "resolves multiple variable references in one element by enumerating all combinations" do
-        expect(v.expand_varref("cflag: ${CFLAGS}, cpppath: ${CPPPATH}, compiler: ${compiler}")).to eq([
+        expect(v.expand_varref("cflag: ${CFLAGS}, cpppath: ${CPPPATH}, compiler: ${compiler}", :lambda_args)).to eq([
           "cflag: -Wall, cpppath: dir1, compiler: gcc",
           "cflag: -O2, cpppath: dir1, compiler: gcc",
           "cflag: -Wall, cpppath: dir2, compiler: gcc",
@@ -153,10 +153,19 @@ module Rscons
         ])
       end
       it "returns an empty string when a variable reference refers to a non-existent variable" do
-        expect(v.expand_varref("${not_here}")).to eq("")
+        expect(v.expand_varref("${not_here}", :lambda_args)).to eq("")
       end
-      it "raises an error when a variable reference refers to an unhandled type" do
+      it "calls a lambda with the given lambda arguments" do
-        expect { v.expand_varref("${hash}") }.to raise_error /I do not know how to expand a variable reference to a Hash/
+        expect(v.expand_varref("${lambda}", [v: "fez"])).to eq("fez--12")
+      end
+      it "raises an error when given an invalid argument" do
+        expect { v.expand_varref({a: :b}, :lambda_args) }.to raise_error /Unknown varref type: Hash/
+      end
+      it "raises an error when an expanded variable is an unexpected type" do
+        expect(v).to receive(:[]).at_least(1).times.with("bad").and_return("bad_val")
+        expect(v).to receive(:expand_varref).with("bad_val", :lambda_args).and_return({a: :b})
+        expect(v).to receive(:expand_varref).and_call_original
+        expect { v.expand_varref("${bad}", :lambda_args) }.to raise_error /I do not know how to expand a variable reference to a Hash/
       end
     end
   end