bundle update

It really wasn't necessary since Cache#write is not called often.

CHANGELOG.md

@@ -0,0 +1,210 @@
+## ChangeLog
+
+### v1.17.0
+
+#### New Features
+
+- allow construction variable expansion on `true` and `false` values.
+- remove makefile target name check when parsing dependencies
+
+### v1.16.0
+
+#### New Features
+
+- Add `Rscons.glob`
+- Support command-line variables
+- improve debuggability of cache.up_to_date?
+- allow passing a VarSet into cache methods
+
+#### Fixes
+
+- generate dependencies for D builds
+
+### v1.15.0
+
+- allow json 1.x or 2.x
+
+### v1.14.0
+
+#### New Features
+
+- #45 - Add Rscons::VarSet#values_at
+
+#### Fixes
+
+- #44 - Environment#print_builder_run_message should support string commands
+
+### v1.13.0
+
+#### New Features
+
+- #43 - Add ability to record side-effect file production
+
+### v1.12.0
+
+#### New Features
+
+- #40 - env.depends should imply env.build_after
+- #41 - be more colorful
+
+#### Fixes
+
+- #39 - wait for in-progress subcommands to complete on build failure
+- #42 - cloned Environments should inherit n_threads
+
+### v1.11.1
+
+#### Fixes
+
+- fix the circular build dependency detection logic
+
+### v1.11.0
+
+#### New Features
+
+- Change default Environment :clone option to :all to clone all attributes
+- #38 - raise error when circular dependencies are found
+- #34 - Allow overriding n_threads on a per-Environment level
+
+#### Fixes
+
+- #35 - env.build_after should expand paths
+- #36 - SHCFLAGS and SHCXXFLAGS should inherit non-SH flags by default
+- #37 - Fix non-blocking thread-wait if Rscons.n_threads is set to 0
+
+### v1.10.0
+
+#### New Features
+
+- #23 - add parallelization - builds are now parallelized by default
+- #31 - add LEXSUFFIX, YACCSUFFIX construction variables
+- #30 - place object files for absolute source paths under build_root
+- #28 - support redirecting standard output using the Command builder
+- Always use a build root and default it to "build"
+- Add builder features
+- #8 - add SharedObject and SharedLibrary builders
+
+#### Fixes
+
+- expand target and source paths before calling Builder#create_build_target
+- #29 - fix PROGSUFFIX handling
+- #32 - Pre-build hooks do not respect modified key values
+
+### v1.9.3
+
+- Environment#parse_flags should put -std=XXX flags in CCFLAGS, not CFLAGS
+
+### v1.9.2
+
+- allow phony targets in conjunction with build roots
+
+### v1.9.1
+
+- change *SUFFIX defaults to arrays
+- add various C++ file suffixes
+- use ${INCPREFIX} instead of hard-coded "-I" in Preprocess builder
+
+### v1.9.0
+
+#### New Features
+
+- #6 - add Install and Copy builders
+- #22 - allow overriding Command builder short description with CMD_DESC variable
+- #24 - add "rscons" executable
+- #25 - add support for phony targets given as Symbols instead of Strings
+- #26 - support registering multiple build targets with the same target name
+- #27 - add Directory builder
+
+#### Fixes
+
+- #20 - fix variable references that expand to arrays in build target sources
+- #21 - rework Preprocess builder to consider deep dependencies
+- fix Rscons.set_suffix to append the given suffix if the filename has none
+- remove ${CFLAGS} from default CPP_CMD
+
+### v1.8.1
+
+- fix Environment#dump when construction variables are symbols
+
+### v1.8.0
+
+- new Command builder to execute arbitrary user commands
+- new SimpleBuilder class
+  - create new builders quickly by passing a block to Environment#add_builder
+- improved YARD documentation
+- add Environment#dump to debug Environment construction variables
+
+### 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
+- 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
+  file or an array of target file names

Gemfile.lock

@@ -1,38 +1,36 @@
 PATH
   remote: .
   specs:
-    rscons (1.13.0)
-      json (~> 1.0)
+    rscons (1.17.0)
+      json (>= 1.8, < 3.0)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    diff-lcs (1.2.5)
-    docile (1.1.5)
-    json (1.8.3)
-    rake (10.4.2)
-    rdoc (4.2.0)
-      json (~> 1.4)
-    redcarpet (3.3.3)
-    rspec (3.4.0)
-      rspec-core (~> 3.4.0)
-      rspec-expectations (~> 3.4.0)
-      rspec-mocks (~> 3.4.0)
-    rspec-core (3.4.1)
-      rspec-support (~> 3.4.0)
-    rspec-expectations (3.4.0)
+    diff-lcs (1.3)
+    docile (1.3.2)
+    json (2.2.0)
+    rake (12.3.2)
+    rdoc (6.1.1)
+    rspec (3.8.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+    rspec-core (3.8.2)
+      rspec-support (~> 3.8.0)
+    rspec-expectations (3.8.4)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-mocks (3.4.0)
+      rspec-support (~> 3.8.0)
+    rspec-mocks (3.8.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-support (3.4.1)
-    simplecov (0.11.1)
+      rspec-support (~> 3.8.0)
+    rspec-support (3.8.2)
+    simplecov (0.15.0)
       docile (~> 1.1.0)
-      json (~> 1.8)
+      json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
-    simplecov-html (0.10.0)
-    yard (0.8.7.6)
+    simplecov-html (0.10.2)
+    yard (0.9.20)
 
 PLATFORMS
   ruby
@@ -41,11 +39,10 @@ PLATFORMS
 DEPENDENCIES
   rake
   rdoc
-  redcarpet
   rscons!
   rspec
   simplecov
   yard
 
 BUNDLED WITH
-   1.10.6
+   1.17.3

README.md

@@ -1,7 +1,7 @@
 # Rscons
 
-Rscons is a software construction framework inspired by SCons and implemented
-in Ruby.
+Rscons (https://github.com/holtrop/rscons) is a software construction framework
+inspired by SCons and implemented in Ruby.
 
 [![Gem Version](https://badge.fury.io/rb/rscons.png)](http://badge.fury.io/rb/rscons)
 
@@ -30,7 +30,7 @@ task block or split among multiple tasks.
 ```ruby
 Rscons::Environment.new do |env|
   env["CFLAGS"] << "-Wall"
-  env.Program("program", Dir["src/**/*.c"])
+  env.Program("program", Rscons.glob("src/**/*.c"))
 end
 ```
 
@@ -39,7 +39,7 @@ end
 ```ruby
 Rscons::Environment.new do |env|
   env["DFLAGS"] << "-Wall"
-  env.Program("program", Dir["src/**/*.d"])
+  env.Program("program", Rscons.glob("src/**/*.d"))
 end
 ```
 
@@ -51,7 +51,7 @@ main_env = Rscons::Environment.new do |env|
   env.build_dir("src", "build/main")
   env["CFLAGS"] = ["-DSOME_DEFINE", "-O3"]
   env["LIBS"] = ["SDL"]
-  env.Program("program", Dir["src/**/*.cc"])
+  env.Program("program", Rscons.glob("src/**/*.cc"))
 end
 
 debug_env = main_env.clone do |env|
@@ -59,7 +59,7 @@ debug_env = main_env.clone do |env|
   env.build_dir("src", "build/debug")
   env["CFLAGS"] -= ["-O3"]
   env["CFLAGS"] += ["-g", "-O0"]
-  env.Program("program-debug", Dir["src/**/*.cc"])
+  env.Program("program-debug", Rscons.glob("src/**/*.cc"))
 end
 ```
 
@@ -86,7 +86,7 @@ end
 Rscons::Environment.new do |env|
   env.add_builder(GenerateFoo.new)
   env.GenerateFoo("foo.h", [])
-  env.Program("a.out", Dir["*.c"])
+  env.Program("a.out", Rscons.glob("*.c"))
 end
 ```
 
@@ -111,6 +111,15 @@ Rscons::Environment.new do |env|
 end
 ```
 
+The `Cache#up_to_date?` method accepts an optional 5th parameter which is an
+options Hash. The `:debug` option can be specified in this Hash with a value
+of `true` to aid in debugging builders while developing them. For example:
+
+```ruby
+unless cache.up_to_date?(target, cmd, sources, env, debug: true)
+end
+```
+
 ### Example: Custom Builder That Generates Multiple Output Files
 
 ```ruby
@@ -191,7 +200,7 @@ Rscons::Environment.new do |env|
     end
   end
   env.build_dir("src", "build")
-  env.Program("program", Dir["**/*.cc"])
+  env.Program("program", Rscons.glob("**/*.cc"))
 end
 ```
 
@@ -199,7 +208,7 @@ end
 
 ```ruby
 Rscons::Environment.new do |env|
-  env.Library("mylib.a", Dir["src/**/*.c"])
+  env.Library("mylib.a", Rscons.glob("src/**/*.c"))
 end
 ```
 
@@ -327,7 +336,7 @@ env.Install("dist/share", "share")
 ```ruby
 env.Library(target, sources)
 # Example
-env.Library("lib.a", Dir["src/**/*.c"])
+env.Library("lib.a", Rscons.glob("src/**/*.c"))
 ```
 
 The Library builder creates a static library archive from the given source
@@ -362,7 +371,7 @@ preprocessed output to the target file.
 ```ruby
 env.Program(target, sources)
 # Example
-env.Program("myprog", Dir["src/**/*.cc"])
+env.Program("myprog", Rscons.glob("src/**/*.cc"))
 ```
 
 The Program builder compiles and links the given sources to an executable file.
@@ -375,7 +384,7 @@ This can be controlled with the `PROGSUFFIX` construction variable.
 ```ruby
 env.SharedLibrary(target, sources)
 # Example
-env.SharedLibrary("mydll", Dir["src/**/*.cc"])
+env.SharedLibrary("mydll", Rscons.glob("src/**/*.cc"))
 ```
 
 The SharedLibrary builder compiles and links the given sources to a dynamically
@@ -411,14 +420,14 @@ construction variables can be overridden by the user.
 | ARFLAGS | Array | Static library archiver flags | ["rcs"] |
 | AS | String | Assembler executable | "${CC}" |
 | ASCMD | Array | Assembler command line | ["${AS}", "-c", "-o", "${_TARGET}", "${ASDEPGEN}", "${INCPREFIX}${ASPPPATH}", "${ASPPFLAGS}", "${ASFLAGS}", "${_SOURCES}"] |
-| ASDEPGEN | Array | Assembly dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}"] |
+| ASDEPGEN | Array | Assembly dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}", "-MT", "TARGET"] |
 | ASFLAGS | Array | Assembler flags | [] |
 | ASPPFLAGS | Array | Assembler preprocessor flags | ["${CPPFLAGS}"] |
 | ASPPPATH | Array | Assembler preprocessor path | ["${CPPPATH}"] |
 | ASSUFFIX | Array | Assembly file suffixes | [".S"] |
 | CC | String | C compiler executable | "gcc" |
 | CCCMD | Array | C compiler command line | ["${CC}", "-c", "-o", "${_TARGET}", "${CCDEPGEN}", "${INCPREFIX}${CPPPATH}", "${CPPFLAGS}", "${CFLAGS}", "${CCFLAGS}", "${_SOURCES}"] |
-| CCDEPGEN | Array | C compiler dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}"] |
+| CCDEPGEN | Array | C compiler dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}", "-MT", "TARGET"] |
 | CCFLAGS | Array | Common flags for both C and C++ compiler | [] |
 | CFLAGS | Array | C compiler flags | [] |
 | CPP_CMD | Array | Preprocess command line | ["${_PREPROCESS_CC}", "-E", "${_PREPROCESS_DEPGEN}", "-o", "${_TARGET}", "${INCPREFIX}${CPPPATH}", "${CPPFLAGS}", "${_SOURCES}"] |
@@ -430,12 +439,13 @@ construction variables can be overridden by the user.
 | CSUFFIX | Array | C source file suffixes | [".c"] |
 | CXX | String | C++ compiler executable | "g++" |
 | CXXCMD | Array | C++ compiler command line | ["${CXX}", "-c", "-o", "${_TARGET}", "${CXXDEPGEN}", "${INCPREFIX}${CPPPATH}", "${CPPFLAGS}", "${CXXFLAGS}", "${CCFLAGS}", "${_SOURCES}"] |
-| CXXDEPGEN | Array | C++ compiler dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}"] |
+| CXXDEPGEN | Array | C++ compiler dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}", "-MT", "TARGET"] |
 | CXXFLAGS | Array | C++ compiler flags | [] |
 | CXXSUFFIX | Array | C++ source file suffixes | [".cc", ".cpp", ".cxx", ".C"] |
 | D_IMPORT_PATH | Array | D compiler import path | [] |
 | DC | String | D compiler executable | "gdc" |
-| DCCMD | Array | D compiler command line | ["${DC}", "-c", "-o", "${_TARGET}", "${INCPREFIX}${D_IMPORT_PATH}", "${DFLAGS}", "${_SOURCES}"] |
+| DCCMD | Array | D compiler command line | ["${DC}", "-c", "-o", "${_TARGET}", "${DDEPGEN}", "${INCPREFIX}${D_IMPORT_PATH}", "${DFLAGS}", "${_SOURCES}"] |
+| DDEPGEN | Array | D compiler dependency generation flags | ["-MMD", "-MF", "${_DEPFILE}", "-MT", "TARGET"] |
 | DEPFILESUFFIX | String | Dependency file suffix for Makefile-style dependency rules emitted by the compiler (used internally for temporary dependency files used to determine a source file's dependencies) | ".mf" |
 | DFLAGS | Array | D compiler flags | [] |
 | DISASM_CMD | Array | Disassemble command line | ["${OBJDUMP}", "${DISASM_FLAGS}", "${_SOURCES}"] |
@@ -548,9 +558,19 @@ end
 You can pass multiple dependency files to `Environment#depends`:
 
 ```ruby
-env.depends("my_app", "config/link.ld", "README.txt", *Dir.glob("assets/**/*"))
+env.depends("my_app", "config/link.ld", "README.txt", *Rscons.glob("assets/**/*"))
 ```
 
+### Command-Line Variables
+
+Variables can be specified on the rscons command line. For example:
+
+```
+rscons VAR=val
+```
+
+These variables are accessible in a global VarSet called `Rscons.vars`.
+
 ### Construction Variable Naming
 
 * uppercase strings - the default construction variables that Rscons uses
@@ -562,183 +582,6 @@ env.depends("my_app", "config/link.ld", "README.txt", *Dir.glob("assets/**/*"))
 Documentation for the complete Rscons API can be found at
 http://www.rubydoc.info/github/holtrop/rscons/master.
 
-## Release Notes
-
-### v1.13.0
-
-#### New Features
-
-- #43 - Add ability to record side-effect file production
-
-### v1.12.0
-
-#### New Features
-
-- #40 - env.depends should imply env.build_after
-- #41 - be more colorful
-
-#### Fixes
-
-- #39 - wait for in-progress subcommands to complete on build failure
-- #42 - cloned Environments should inherit n_threads
-
-### v1.11.1
-
-#### Fixes
-
-- fix the circular build dependency detection logic
-
-### v1.11.0
-
-#### New Features
-
-- Change default Environment :clone option to :all to clone all attributes
-- #38 - raise error when circular dependencies are found
-- #34 - Allow overriding n_threads on a per-Environment level
-
-#### Fixes
-
-- #35 - env.build_after should expand paths
-- #36 - SHCFLAGS and SHCXXFLAGS should inherit non-SH flags by default
-- #37 - Fix non-blocking thread-wait if Rscons.n_threads is set to 0
-
-### v1.10.0
-
-#### New Features
-
-- #23 - add parallelization - builds are now parallelized by default
-- #31 - add LEXSUFFIX, YACCSUFFIX construction variables
-- #30 - place object files for absolute source paths under build_root
-- #28 - support redirecting standard output using the Command builder
-- Always use a build root and default it to "build"
-- Add builder features
-- #8 - add SharedObject and SharedLibrary builders
-
-#### Fixes
-
-- expand target and source paths before calling Builder#create_build_target
-- #29 - fix PROGSUFFIX handling
-- #32 - Pre-build hooks do not respect modified key values
-
-### v1.9.3
-
-- Environment#parse_flags should put -std=XXX flags in CCFLAGS, not CFLAGS
-
-### v1.9.2
-
-- allow phony targets in conjunction with build roots
-
-### v1.9.1
-
-- change *SUFFIX defaults to arrays
-- add various C++ file suffixes
-- use ${INCPREFIX} instead of hard-coded "-I" in Preprocess builder
-
-### v1.9.0
-
-#### New Features
-
-- #6 - add Install and Copy builders
-- #22 - allow overriding Command builder short description with CMD_DESC variable
-- #24 - add "rscons" executable
-- #25 - add support for phony targets given as Symbols instead of Strings
-- #26 - support registering multiple build targets with the same target name
-- #27 - add Directory builder
-
-#### Fixes
-
-- #20 - fix variable references that expand to arrays in build target sources
-- #21 - rework Preprocess builder to consider deep dependencies
-- fix Rscons.set_suffix to append the given suffix if the filename has none
-- remove ${CFLAGS} from default CPP_CMD
-
-### v1.8.1
-
-- fix Environment#dump when construction variables are symbols
-
-### v1.8.0
-
-- new Command builder to execute arbitrary user commands
-- new SimpleBuilder class
-  - create new builders quickly by passing a block to Environment#add_builder
-- improved YARD documentation
-- add Environment#dump to debug Environment construction variables
-
-### 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
-- 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
-  file or an array of target file names
-
 ## Contributing
 
 1. Fork it

bin/rscons

@@ -1,3 +1,5 @@
+#!/usr/bin/env ruby
+
 require "rscons/cli"
 
 Rscons::Cli.run(ARGV)

build_tests/build_dir/Rsconsfile

@@ -1,5 +1,5 @@
 Rscons::Environment.new do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'].sort)
+  env.append('CPPPATH' => Rscons.glob('src/**'))
   env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
-  env.Program('build_dir.exe', Dir['src/**/*.c'])
+  env.Program('build_dir.exe', Rscons.glob('src/**/*.c'))
 end

build_tests/build_dir/backward_compatible_build_hooks.rb

@@ -6,7 +6,7 @@ end
 
 Rscons::Environment.new(echo: :command) do |env|
   env.add_builder(MyObject.new)
-  env.append('CPPPATH' => Dir['src/**/*/'].sort)
+  env.append('CPPPATH' => Rscons.glob('src/**'))
   env.add_build_hook do |build_op|
     if build_op[:builder].name == "MyObject" && build_op[:sources].first =~ %r{one\.c}
       build_op[:vars]["CFLAGS"] << "-O1"

build_tests/build_dir/build_dirs_and_root.rb

@@ -1,6 +1,6 @@
 env = Rscons::Environment.new do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'].sort)
+  env.append('CPPPATH' => Rscons.glob('src/**/*/'))
   env.build_dir("src", "build")
   env.build_root = "build_root"
-  env.Program('build_dir.exe', Dir['src/**/*.c'])
+  env.Program('build_dir.exe', Rscons.glob('src/**/*.c'))
 end

build_tests/build_dir/build_hooks.rb

@@ -1,5 +1,5 @@
 Rscons::Environment.new(echo: :command) do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'].sort)
+  env.append('CPPPATH' => Rscons.glob('src/**/*/'))
   env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
   env.add_build_hook do |build_op|
     if build_op[:target] =~ %r{build_one/.*\.o}
@@ -8,5 +8,5 @@ Rscons::Environment.new(echo: :command) do |env|
       build_op[:vars]["CFLAGS"] << "-O2"
     end
   end
-  env.Program('build_hook.exe', Dir['src/**/*.c'].sort)
+  env.Program('build_hook.exe', Rscons.glob('src/**/*.c'))
 end

build_tests/build_dir/carat.rb

@@ -1,8 +1,8 @@
 Rscons::Environment.new(echo: :command) do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'].sort)
+  env.append('CPPPATH' => Rscons.glob('src/**').sort)
   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.exe", Dir['src/**/*.c'] + ["^/one.o"])
+  env.Program("build_dir.exe", Rscons.glob('src/**/*.c') + ["^/one.o"])
 end

build_tests/build_dir/csuffix.rb

@@ -1,6 +1,6 @@
 Rscons::Environment.new do |env|
   env["CSUFFIX"] = %w[.yargh .c]
   env["CFLAGS"] += %w[-x c]
-  env["CPPPATH"] += Dir["src/**/"]
-  env.Program("build_dir.exe", Dir["src/**/*.{c,yargh}"])
+  env["CPPPATH"] += Rscons.glob("src/**")
+  env.Program("build_dir.exe", Rscons.glob("src/**/*.{c,yargh}"))
 end

build_tests/build_dir/echo_command_ruby_builder.rb

@@ -0,0 +1,5 @@
+Rscons::Environment.new do |env|
+  env.echo = :command
+  env.Install("inst.exe", "install.rb")
+end
+

build_tests/build_dir/echo_command_string.rb

@@ -0,0 +1,13 @@
+class MyBuilder < Rscons::Builder
+  def run(options)
+    env, target = options.values_at(:env, :target)
+    env.print_builder_run_message("MyBuilder #{target}", "MyBuilder #{target} command")
+    target
+  end
+end
+
+Rscons::Environment.new do |env|
+  env.echo = :command
+  env.add_builder(MyBuilder.new)
+  env.MyBuilder("foo")
+end

build_tests/build_dir/no_match_build_dir.rb

@@ -1,6 +1,6 @@
 Rscons::Environment.new do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'].sort)
+  env.append('CPPPATH' => Rscons.glob('src/**'))
   env.build_dir("src2", "build")
   env.build_root = "build_root"
-  env.Program('build_dir.exe', Dir['src/**/*.c'])
+  env.Program('build_dir.exe', Rscons.glob('src/**/*.c'))
 end

build_tests/build_dir/slashes.rb

@@ -1,6 +1,6 @@
 Rscons::Environment.new do |env|
-  env.append("CPPPATH" => Dir["src/**/*/"].sort)
+  env.append("CPPPATH" => Rscons.glob("src/**"))
   env.build_dir("src/one/", "build_one/")
   env.build_dir("src/two", "build_two")
-  env.Program("build_dir.exe", Dir["src/**/*.c"])
+  env.Program("build_dir.exe", Rscons.glob("src/**/*.c"))
 end

build_tests/d/Rsconsfile

@@ -1,3 +1,3 @@
 Rscons::Environment.new(echo: :command) do |env|
-  env.Program("hello-d.exe", Dir["*.d"])
+  env.Program("hello-d.exe", Rscons.glob("*.d"))
 end

build_tests/d/main.d

@@ -1,6 +1,7 @@
 import std.stdio;
+import mod;
 
 void main()
 {
-    writeln("Hello from D!");
+    writeln("Hello from D, value is ", Klass.VAL, "!");
 }

build_tests/d/mod.d

@@ -0,0 +1,4 @@
+class Klass
+{
+    enum VAL = 42;
+};

build_tests/library/override_arcmd.rb

@@ -1,4 +1,4 @@
 Rscons::Environment.new(echo: :command) do |env|
   env["ARCMD"] = %w[ar rcf ${_TARGET} ${_SOURCES}]
-  env.Library("lib.a", Dir["*.c"].sort)
+  env.Library("lib.a", Rscons.glob("*.c"))
 end

build_tests/shared_library/Rsconsfile

@@ -1,11 +1,11 @@
 Rscons::Environment.new do |env|
   env["CPPPATH"] << "src/lib"
-  libmine = env.SharedLibrary("mine", Dir["src/lib/*.c"])
+  libmine = env.SharedLibrary("mine", Rscons.glob("src/lib/*.c"))
   env.Program("test-shared.exe",
-              Dir["src/*.c"],
+              Rscons.glob("src/*.c"),
               "LIBPATH" => %w[.],
               "LIBS" => %w[mine])
   env.build_after("test-shared.exe", libmine.to_s)
   env.Program("test-static.exe",
-              Dir["src/**/*.c"])
+              Rscons.glob("src/**/*.c"))
 end

build_tests/shared_library/shared_library_cxx.rb

@@ -1,11 +1,11 @@
 Rscons::Environment.new do |env|
   env["CPPPATH"] << "src/lib"
-  libmine = env.SharedLibrary("mine", Dir["src/lib/*.cc"])
+  libmine = env.SharedLibrary("mine", Rscons.glob("src/lib/*.cc"))
   env.Program("test-shared.exe",
-              Dir["src/*.cc"],
+              Rscons.glob("src/*.cc"),
               "LIBPATH" => %w[.],
               "LIBS" => %w[mine])
   env.build_after("test-shared.exe", libmine.to_s)
   env.Program("test-static.exe",
-              Dir["src/**/*.cc"])
+              Rscons.glob("src/**/*.cc"))
 end

build_tests/shared_library/shared_library_d.rb

@@ -1,8 +1,8 @@
 Rscons::Environment.new do |env|
   env["CPPPATH"] << "src/lib"
-  libmine = env.SharedLibrary("mine", Dir["src/lib/*.d"])
+  libmine = env.SharedLibrary("mine", Rscons.glob("src/lib/*.d"))
   env.Program("test-shared.exe",
-              Dir["src/*.c"],
+              Rscons.glob("src/*.c"),
               "LIBPATH" => %w[.],
               "LIBS" => %w[mine])
   env.build_after("test-shared.exe", libmine.to_s)

build_tests/shared_library/shared_library_set_shld.rb

@@ -1,12 +1,12 @@
 Rscons::Environment.new do |env|
   env["CPPPATH"] << "src/lib"
   env["SHLD"] = "gcc"
-  libmine = env.SharedLibrary("mine", Dir["src/lib/*.c"])
+  libmine = env.SharedLibrary("mine", Rscons.glob("src/lib/*.c"))
   env.Program("test-shared.exe",
-              Dir["src/*.c"],
+              Rscons.glob("src/*.c"),
               "LIBPATH" => %w[.],
               "LIBS" => %w[mine])
   env.build_after("test-shared.exe", libmine.to_s)
   env.Program("test-static.exe",
-              Dir["src/**/*.c"])
+              Rscons.glob("src/**/*.c"))
 end

build_tests/simple/cache_debugging.rb

@@ -0,0 +1,34 @@
+class DebugBuilder < Rscons::Builder
+  def run(options)
+    target, sources, cache, env, vars = options.values_at(:target, :sources, :cache, :env, :vars)
+    command = %W[gcc -c -o #{target} #{sources.first}]
+    if Rscons.vars["command_change"]
+      command += %w[-Wall]
+    end
+    if Rscons.vars["new_dep"]
+      sources += ["extra"]
+    end
+    if Rscons.vars["strict_deps1"]
+      sources += ["extra"]
+      strict_deps = true
+    end
+    if Rscons.vars["strict_deps2"]
+      sources = ["extra"] + sources
+      strict_deps = true
+    end
+    unless cache.up_to_date?(target, command, sources, env, debug: true, strict_deps: strict_deps)
+      desc = "#{self.class.name} #{target}"
+      return false unless env.execute(desc, command)
+      cache.register_build(target, command, sources, env)
+    end
+    target
+  end
+end
+
+Rscons::Environment.new do |env|
+  env.add_builder(DebugBuilder.new)
+  if Rscons.vars["new_user_dep"]
+    env.depends("foo.o", "new_dep")
+  end
+  env.DebugBuilder("foo.o", "simple.c")
+end

build_tests/simple/cache_varset.rb

@@ -0,0 +1,20 @@
+class TestBuilder < Rscons::Builder
+  def run(options)
+    target, sources, cache, env = options.values_at(:target, :sources, :cache, :env)
+    command = Rscons::VarSet.new("A" => "a", "B" => "b")
+    unless cache.up_to_date?(target, command, sources, env)
+      File.open(target, "w") do |fh|
+        fh.puts("hi")
+      end
+      msg = "#{self.class.name} #{target}"
+      env.print_builder_run_message(msg, msg)
+      cache.register_build(target, command, sources, env)
+    end
+    target
+  end
+end
+
+Rscons::Environment.new do |env|
+  env.add_builder(TestBuilder.new)
+  env.TestBuilder("foo")
+end

build_tests/simple/cvar_array.rb

@@ -1,4 +1,4 @@
 Rscons::Environment.new do |env|
-  env["sources"] = Dir["*.c"].sort
+  env["sources"] = Rscons.glob("*.c")
   env.Program("simple.exe", "${sources}")
 end

lib/rscons.rb

@@ -55,6 +55,11 @@ module Rscons
     #   Whether to output ANSI color escape sequences.
     attr_accessor :do_ansi_color
 
+    # @since 1.16.0
+    # @return [VarSet]
+    #   Access any variables set on the rscons command-line.
+    attr_reader :vars
+
     # Remove all generated files.
     #
     # @return [void]
@@ -165,6 +170,35 @@ module Rscons
       @command_executer = val
     end
 
+    # Return a list of paths matching the specified pattern(s).
+    #
+    # @since 1.16.0
+    #
+    # A pattern can contain a "/**" component to recurse through directories.
+    # If the pattern ends with "/**" then only the recursive list of
+    # directories will be returned.
+    #
+    # Examples:
+    # - "src/**": return all directories under "src", recursively (including
+    #   "src" itself).
+    # - "src/**/*": return all files and directories recursively under the src
+    #   directory.
+    # - "src/**/*.c": return all .c files recursively under the src directory.
+    # - "dir/*/": return all directories in dir, but no files.
+    #
+    # @return [Array<String>] Paths matching the specified pattern(s).
+    def glob(*patterns)
+      require "pathname"
+      patterns.reduce([]) do |result, pattern|
+        if pattern.end_with?("/**")
+          pattern += "/"
+        end
+        result += Dir.glob(pattern).map do |path|
+          Pathname.new(path.gsub("\\", "/")).cleanpath.to_s
+        end
+      end.sort
+    end
+
     private
 
     # Determine the number of threads to use by default.
@@ -203,6 +237,7 @@ module Rscons
   end
 
   @n_threads = determine_n_threads
+  @vars = VarSet.new
 
 end
 

lib/rscons/builders/directory.rb

@@ -20,8 +20,7 @@ module Rscons
           Ansi.write($stderr, :red, "Error: `#{target}' already exists and is not a directory", :reset, "\n")
           false
         else
-          desc = "Directory #{target}"
-          env.print_builder_run_message(desc, desc)
+          env.print_builder_run_message("Directory #{target}", nil)
           cache.mkdir_p(target)
           target
         end

lib/rscons/builders/install.rb

@@ -43,8 +43,7 @@ module Rscons
           # Check the cache and copy if necessary
           unless cache.up_to_date?(dest, :Copy, [src], env)
             unless printed_message
-              desc = "#{name} #{target}"
-              env.print_builder_run_message(desc, desc)
+              env.print_builder_run_message("#{name} #{target}", nil)
               printed_message = true
             end
             cache.mkdir_p(File.dirname(dest))

lib/rscons/builders/object.rb

@@ -54,8 +54,9 @@ module Rscons
           'DC' => 'gdc',
           'DFLAGS' => [],
           'DSUFFIX' => ['.d'],
+          'DDEPGEN' => ['-MMD', '-MF', '${_DEPFILE}'],
           'D_IMPORT_PATH' => [],
-          'DCCMD' => ['${DC}', '-c', '-o', '${_TARGET}', '${INCPREFIX}${D_IMPORT_PATH}', '${DFLAGS}', '${_SOURCES}'],
+          'DCCMD' => ['${DC}', '-c', '-o', '${_TARGET}', '${DDEPGEN}', '${INCPREFIX}${D_IMPORT_PATH}', '${DFLAGS}', '${_SOURCES}'],
         }
       end
 
@@ -114,7 +115,7 @@ module Rscons
         if options[:command_status]
           target, deps, cache, env, vars = options.values_at(:target, :sources, :cache, :env, :vars)
           if File.exists?(vars['_DEPFILE'])
-            deps += Environment.parse_makefile_deps(vars['_DEPFILE'], target)
+            deps += Environment.parse_makefile_deps(vars['_DEPFILE'])
             FileUtils.rm_f(vars['_DEPFILE'])
           end
           cache.register_build(target, options[:tc].command, deps.uniq, env)

lib/rscons/builders/preprocess.rb

@@ -55,7 +55,7 @@ module Rscons
         if options[:command_status]
           target, deps, cache, env, vars = options.values_at(:target, :sources, :cache, :env, :vars)
           if File.exists?(vars['_DEPFILE'])
-            deps += Environment.parse_makefile_deps(vars['_DEPFILE'], nil)
+            deps += Environment.parse_makefile_deps(vars['_DEPFILE'])
             FileUtils.rm_f(vars['_DEPFILE'])
           end
           cache.register_build(target, options[:tc].command, deps.uniq, env)

lib/rscons/builders/shared_object.rb

@@ -100,7 +100,7 @@ module Rscons
         if options[:command_status]
           target, deps, cache, env, vars = options.values_at(:target, :sources, :cache, :env, :vars)
           if File.exists?(vars['_DEPFILE'])
-            deps += Environment.parse_makefile_deps(vars['_DEPFILE'], target)
+            deps += Environment.parse_makefile_deps(vars['_DEPFILE'])
             FileUtils.rm_f(vars['_DEPFILE'])
           end
           cache.register_build(target, options[:tc].command, deps.uniq, env)

lib/rscons/cache.rb

@@ -85,17 +85,14 @@ module Rscons
       @lookup_checksums = {}
     end
 
-    # Write the cache to disk to be loaded next time.
+    # Write the cache to disk.
     #
     # @return [void]
     def write
-      if @dirty || (@cache["version"] != VERSION)
-        @cache["version"] = VERSION
-        File.open(CACHE_FILE, "w") do |fh|
-          fh.puts(JSON.dump(@cache))
-        end
+      @cache["version"] = VERSION
+      File.open(CACHE_FILE, "w") do |fh|
+        fh.puts(JSON.dump(@cache))
       end
-      @dirty = false
     end
 
     # Check if target(s) are up to date.
@@ -111,6 +108,10 @@ module Rscons
     # @param deps [Array<String>] List of the target's dependency files.
     # @param env [Environment] The Rscons::Environment.
     # @param options [Hash] Optional options.
+    # @option options [Boolean] :debug
+    #   If turned on, this causes the Cache to print messages explaining why
+    #   a build target is out of date. This could aid a builder author in
+    #   debugging the operation of their builder.
     # @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
@@ -133,39 +134,79 @@ module Rscons
 
         unless Rscons.phony_target?(target)
           # target file must exist on disk
-          return false unless File.exists?(target)
+          unless File.exists?(target)
+            if options[:debug]
+              puts "Target #{target} needs rebuilding because it does not exist on disk"
+            end
+            return false
+          end
         end
 
         # target must be registered in the cache
-        return false unless @cache["targets"].has_key?(cache_key)
+        unless @cache["targets"].has_key?(cache_key)
+          if options[:debug]
+            puts "Target #{target} needs rebuilding because there is no cached build information for it"
+          end
+          return false
+        end
 
         unless Rscons.phony_target?(target)
           # target must have the same checksum as when it was built last
-          return false unless @cache["targets"][cache_key]["checksum"] == lookup_checksum(target)
+          unless @cache["targets"][cache_key]["checksum"] == lookup_checksum(target)
+            if options[:debug]
+              puts "Target #{target} needs rebuilding because it has been changed on disk since being built last"
+            end
+            return false
+          end
         end
 
         # command used to build target must be identical
-        return false unless @cache["targets"][cache_key]["command"] == Digest::MD5.hexdigest(command.inspect)
+        unless @cache["targets"][cache_key]["command"] == Digest::MD5.hexdigest(command.inspect)
+          if options[:debug]
+            puts "Target #{target} needs rebuilding because the command used to build it has changed"
+          end
+          return false
+        end
 
         cached_deps = @cache["targets"][cache_key]["deps"] || []
         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
+          unless deps == cached_deps_fnames
+            if options[:debug]
+              puts "Target #{target} needs rebuilding because the :strict_deps option is given and the set of dependencies does not match the previous set of dependencies"
+            end
+            return false
+          end
         else
           # all dependencies passed in must exist in cache (but cache may have more)
-          return false unless (Set.new(deps) - Set.new(cached_deps_fnames)).empty?
+          unless (Set.new(deps) - Set.new(cached_deps_fnames)).empty?
+            if options[:debug]
+              puts "Target #{target} needs rebuilding because there are new dependencies"
+            end
+            return false
+          end
         end
 
         # set of user dependencies must match
         user_deps = env.get_user_deps(target) || []
         cached_user_deps = @cache["targets"][cache_key]["user_deps"] || []
         cached_user_deps_fnames = cached_user_deps.map { |dc| dc["fname"] }
-        return false unless user_deps == cached_user_deps_fnames
+        unless user_deps == cached_user_deps_fnames
+          if options[:debug]
+            puts "Target #{target} needs rebuilding because the set of user-specified dependency files has changed"
+          end
+          return false
+        end
 
         # 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"])
+          unless dep_cache["checksum"] == lookup_checksum(dep_cache["fname"])
+            if options[:debug]
+              puts "Target #{target} needs rebuilding because dependency file #{dep_cache["fname"]} has changed"
+            end
+            return false
+          end
         end
       end
 
@@ -205,7 +246,6 @@ module Rscons
             }
           end,
         }
-        @dirty = true
       end
     end
 
@@ -228,9 +268,8 @@ module Rscons
         next if parts[i] == ""
         subpath = File.join(*parts[0, i + 1])
         unless File.exists?(subpath)
-          FileUtils.mkdir(subpath)
+          FileUtils.mkdir_p(subpath)
           @cache["directories"][subpath] = true
-          @dirty = true
         end
       end
     end
@@ -271,7 +310,6 @@ module Rscons
       @cache["targets"] ||= {}
       @cache["directories"] ||= {}
       @lookup_checksums = {}
-      @dirty = false
     end
 
     # Return a file's checksum, or the previously calculated checksum for

lib/rscons/cli.rb

@@ -60,6 +60,12 @@ module Rscons
 
         end.parse!(argv)
 
+        argv.each do |arg|
+          if arg =~ /^([^=]+)=(.*)$/
+            Rscons.vars[$1] = $2
+          end
+        end
+
         if rsconsfile
           unless File.exists?(rsconsfile)
             $stderr.puts "Cannot read #{rsconsfile}"

lib/rscons/environment.rb

@@ -385,12 +385,12 @@ module Rscons
 
     # Expand a construction variable reference.
     #
-    # @param varref [Array, String] Variable reference to expand.
+    # @param varref [nil, String, Array, Proc, Symbol, TrueClass, FalseClass] Variable reference to expand.
     # @param extra_vars [Hash, VarSet]
     #   Extra variables to use in addition to (or replace) the Environment's
     #   construction variables when expanding the variable reference.
     #
-    # @return [Array, String] Expansion of the variable reference.
+    # @return [nil, String, Array, Symbol, TrueClass, FalseClass] Expansion of the variable reference.
     def expand_varref(varref, extra_vars = nil)
       vars = if extra_vars.nil?
                @varset
@@ -885,7 +885,13 @@ module Rscons
     def print_builder_run_message(short_description, command)
       case @echo
       when :command
-        message = command_to_s(command) if command
+        if command.is_a?(Array)
+          message = command_to_s(command)
+        elsif command.is_a?(String)
+          message = command
+        elsif short_description.is_a?(String)
+          message = short_description
+        end
       when :short
         message = short_description if short_description
       end
@@ -1059,16 +1065,14 @@ module Rscons
       end
     end
 
-    # Parse dependencies for a given target from a Makefile.
+    # Parse dependencies from a Makefile.
     #
     # This method is used internally by Rscons builders.
     #
     # @param mf_fname [String] File name of the Makefile to read.
-    # @param target [String, nil]
-    #   Name of the target to gather dependencies for, nil for any/all.
     #
     # @return [Array<String>] Paths of dependency files.
-    def self.parse_makefile_deps(mf_fname, target)
+    def self.parse_makefile_deps(mf_fname)
       deps = []
       buildup = ''
       File.read(mf_fname).each_line do |line|
@@ -1076,11 +1080,9 @@ module Rscons
           buildup += ' ' + $1
         else
           buildup += ' ' + line
-          if buildup =~ /^(.*): (.*)$/
-            mf_target, mf_deps = $1.strip, $2
-            if target.nil? or mf_target == target
-              deps += mf_deps.split(' ').map(&:strip)
-            end
+          if buildup =~ /^.*: (.*)$/
+            mf_deps = $1
+            deps += mf_deps.split(' ').map(&:strip)
           end
           buildup = ''
         end

lib/rscons/varset.rb

@@ -86,40 +86,50 @@ module Rscons
     # Replace "$!{var}" variable references in varref with the expanded
     # variables' values, recursively.
     #
-    # @param varref [nil, String, Array, Proc]
+    # @param varref [nil, String, Array, Proc, Symbol, TrueClass, FalseClass]
     #   Value containing references to variables.
     # @param lambda_args [Array]
     #   Arguments to pass to any lambda variable values to be expanded.
     #
-    # @return [nil, String, Array]
+    # @return [nil, String, Array, Symbol, TrueClass, FalseClass]
     #   Expanded value with "$!{var}" variable references replaced.
     def expand_varref(varref, lambda_args)
-      if varref.is_a?(String)
+      case varref
+      when Symbol, true, false, nil
+        varref
+      when String
         if varref =~ /^(.*)\$\{([^}]+)\}(.*)$/
           prefix, varname, suffix = $1, $2, $3
+          prefix = expand_varref(prefix, lambda_args) unless prefix.empty?
           varval = expand_varref(self[varname], lambda_args)
-          if varval.is_a?(String) or varval.nil?
-            expand_varref("#{prefix}#{varval}#{suffix}", lambda_args)
-          elsif varval.is_a?(Array)
-            varval.map {|vv| expand_varref("#{prefix}#{vv}#{suffix}", lambda_args)}.flatten
+          # suffix needs no expansion since the regex matches the last occurence
+          case varval
+          when Symbol, true, false, nil, String
+            if prefix.is_a?(Array)
+              prefix.map {|p| "#{p}#{varval}#{suffix}"}
+            else
+              "#{prefix}#{varval}#{suffix}"
+            end
+          when Array
+            if prefix.is_a?(Array)
+              varval.map {|vv| prefix.map {|p| "#{p}#{vv}#{suffix}"}}.flatten
+            else
+              varval.map {|vv| "#{prefix}#{vv}#{suffix}"}
+            end
           else
-            raise "I do not know how to expand a variable reference to a #{varval.class.name} (from #{varname.inspect} => #{self[varname].inspect})"
+            raise "Unknown construction variable type: #{varval.class} (from #{varname.inspect} => #{self[varname].inspect})"
           end
         else
           varref
         end
-      elsif varref.is_a?(Array)
+      when Array
         varref.map do |ent|
           expand_varref(ent, lambda_args)
         end.flatten
-      elsif varref.is_a?(Proc)
+      when Proc
         expand_varref(varref[*lambda_args], lambda_args)
-      elsif varref.nil?
-        nil
-      elsif varref.is_a?(Symbol)
-        varref
       else
-        raise "Unknown varref type: #{varref.class} (#{varref.inspect})"
+        raise "Unknown construction variable type: #{varref.class} (#{varref.inspect})"
       end
     end
 
@@ -143,6 +153,26 @@ module Rscons
       end
     end
 
+    # Return a String representing the VarSet.
+    #
+    # @return [String] Representation of the VarSet.
+    def inspect
+      to_h.inspect
+    end
+
+    # Return an array containing the values associated with the given keys.
+    #
+    # @param keys [Array<String, Symbol>]
+    #   Keys to look up in the VarSet.
+    #
+    # @return [Array]
+    #   An array containing the values associated with the given keys.
+    def values_at(*keys)
+      keys.map do |key|
+        self[key]
+      end
+    end
+
     private
 
     # Move all VarSet variables into the copy-on-access list.

lib/rscons/version.rb

@@ -1,4 +1,4 @@
 module Rscons
   # gem version
-  VERSION = "1.13.0"
+  VERSION = "1.17.0"
 end

rscons.gemspec

@@ -18,12 +18,11 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
 
-  gem.add_dependency "json", "~> 1.0"
+  gem.add_dependency "json", ">= 1.8", "< 3.0"
 
   gem.add_development_dependency "rspec"
   gem.add_development_dependency "rake"
   gem.add_development_dependency "simplecov"
   gem.add_development_dependency "yard"
   gem.add_development_dependency "rdoc"
-  gem.add_development_dependency "redcarpet"
 end

spec/build_tests_spec.rb

@@ -74,6 +74,8 @@ describe Rscons do
     command_name = "#{command_prefix}#{@statics[:build_test_id]}"
     File.open("_simplecov_setup.rb", "w") do |fh|
       fh.puts <<EOF
+require "bundler"
+Bundler.setup
 require "simplecov"
 class MyFormatter
   def format(*args)
@@ -91,6 +93,7 @@ end
 $LOAD_PATH.unshift(#{@owd.inspect} + "/lib")
 # force color off
 ENV["TERM"] = nil
+#{options[:ruby_setup_code]}
 EOF
     end
     stdout, stderr, status = nil, nil, nil
@@ -249,8 +252,8 @@ EOF
     result = run_test(rsconsfile: "carat.rb")
     expect(result.stderr).to eq ""
     expect(Set[*lines(result.stdout)]).to eq Set[
-      %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 -c -o build_root/one.o -MMD -MF build_root/one.mf -Isrc -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 -Isrc/one -Isrc/two src/two/two.c},
       %Q{gcc -o build_dir.exe build_root/src/two/two.o build_root/one.o},
     ]
   end
@@ -392,8 +395,8 @@ EOF
     result = run_test(rsconsfile: "build_hooks.rb")
     expect(result.stderr).to eq ""
     expect(Set[*lines(result.stdout)]).to eq Set[
-      '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 -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.exe build_one/one.o build_two/two.o',
     ]
     expect(`./build_hook.exe`).to eq "Hello from two()\n"
@@ -429,11 +432,31 @@ EOF
       test_dir("d")
       result = run_test
       expect(result.stderr).to eq ""
-      expect(lines(result.stdout)).to eq [
-        "gdc -c -o build/main.o main.d",
-        "gdc -o hello-d.exe build/main.o",
-      ]
-      expect(`./hello-d.exe`.rstrip).to eq "Hello from D!"
+      slines = lines(result.stdout)
+      expect(slines).to include("gdc -c -o build/main.o -MMD -MF build/main.mf main.d")
+      expect(slines).to include("gdc -c -o build/mod.o -MMD -MF build/mod.mf mod.d")
+      expect(slines.last).to eq("gdc -o hello-d.exe build/main.o build/mod.o")
+      expect(`./hello-d.exe`.rstrip).to eq "Hello from D, value is 42!"
+    end
+
+    it "does dependency generation for D sources" do
+      test_dir("d")
+      result = run_test
+      expect(result.stderr).to eq ""
+      slines = lines(result.stdout)
+      expect(slines).to include("gdc -c -o build/main.o -MMD -MF build/main.mf main.d")
+      expect(slines).to include("gdc -c -o build/mod.o -MMD -MF build/mod.mf mod.d")
+      expect(slines.last).to eq("gdc -o hello-d.exe build/main.o build/mod.o")
+      expect(`./hello-d.exe`.rstrip).to eq "Hello from D, value is 42!"
+      fcontents = File.read("mod.d", mode: "rb").sub("42", "33")
+      File.open("mod.d", "wb") {|fh| fh.write(fcontents)}
+      result = run_test
+      expect(result.stderr).to eq ""
+      slines = lines(result.stdout)
+      expect(slines).to include("gdc -c -o build/main.o -MMD -MF build/main.mf main.d")
+      expect(slines).to include("gdc -c -o build/mod.o -MMD -MF build/mod.mf mod.d")
+      expect(slines.last).to eq("gdc -o hello-d.exe build/main.o build/mod.o")
+      expect(`./hello-d.exe`.rstrip).to eq "Hello from D, value is 33!"
     end
 
     it "creates shared libraries using D" do
@@ -769,6 +792,22 @@ EOF
     expect(lines(result.stdout)).to eq ["165"]
   end
 
+  it "prints a builder's short description with 'command' echo mode if there is no command" do
+    test_dir("build_dir")
+
+    result = run_test(rsconsfile: "echo_command_ruby_builder.rb")
+    expect(result.stderr).to eq ""
+    expect(lines(result.stdout)).to eq ["Install inst.exe"]
+  end
+
+  it "supports a string for a builder's echoed 'command' with Environment#print_builder_run_message" do
+    test_dir("build_dir")
+
+    result = run_test(rsconsfile: "echo_command_string.rb")
+    expect(result.stderr).to eq ""
+    expect(lines(result.stdout)).to eq ["MyBuilder foo command"]
+  end
+
   context "colored output" do
     it "does not output in color with --color=off" do
       test_dir("simple")
@@ -857,8 +896,8 @@ EOF
       result = run_test(rsconsfile: "backward_compatible_build_hooks.rb")
       expect(result.stderr).to eq ""
       expect(Set[*lines(result.stdout)]).to eq Set[
-        'gcc -c -o one.o -MMD -MF one.mf -Isrc/one/ -Isrc/two/ -O1 src/two/two.c',
-        'gcc -c -o two.o -MMD -MF two.mf -Isrc/one/ -Isrc/two/ -O2 src/two/two.c'
+        'gcc -c -o one.o -MMD -MF one.mf -Isrc -Isrc/one -Isrc/two -O1 src/two/two.c',
+        'gcc -c -o two.o -MMD -MF two.mf -Isrc -Isrc/one -Isrc/two -O2 src/two/two.c'
       ]
       expect(File.exists?('one.o')).to be_truthy
       expect(File.exists?('two.o')).to be_truthy
@@ -1225,6 +1264,81 @@ EOF
         "LD simple.exe",
       ]
     end
+
+    it "allows a VarSet to be passed in as the command parameter" do
+      test_dir("simple")
+      result = run_test(rsconsfile: "cache_varset.rb")
+      expect(result.stderr).to eq ""
+      expect(lines(result.stdout)).to eq [
+        "TestBuilder foo",
+      ]
+      result = run_test(rsconsfile: "cache_varset.rb")
+      expect(result.stderr).to eq ""
+      expect(result.stdout).to eq ""
+    end
+
+    context "debugging" do
+      it "prints a message when the target does not exist" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because it does not exist on disk/
+      end
+
+      it "prints a message when there is no cached build information for the target" do
+        test_dir("simple")
+        FileUtils.touch("foo.o")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because there is no cached build information for it/
+      end
+
+      it "prints a message when the target file has changed on disk" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        File.open("foo.o", "wb") {|fh| fh.puts "hi"}
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because it has been changed on disk since being built last/
+      end
+
+      it "prints a message when the command has changed" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        result = run_test(rsconsfile: "cache_debugging.rb", rscons_args: %w[command_change=yes])
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because the command used to build it has changed/
+      end
+
+      it "prints a message when strict_deps is in use and the set of dependencies does not match" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb", rscons_args: %w[strict_deps1=yes])
+        result = run_test(rsconsfile: "cache_debugging.rb", rscons_args: %w[strict_deps2=yes])
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because the :strict_deps option is given and the set of dependencies does not match the previous set of dependencies/
+      end
+
+      it "prints a message when there is a new dependency" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        result = run_test(rsconsfile: "cache_debugging.rb", rscons_args: %w[new_dep=yes])
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because there are new dependencies/
+      end
+
+      it "prints a message when there is a new user-specified dependency" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        result = run_test(rsconsfile: "cache_debugging.rb", rscons_args: %w[new_user_dep=yes])
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because the set of user-specified dependency files has changed/
+      end
+
+      it "prints a message when a dependency file has changed" do
+        test_dir("simple")
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        f = File.read("simple.c", mode: "rb")
+        f += "\n"
+        File.open("simple.c", "wb") do |fh|
+          fh.write(f)
+        end
+        result = run_test(rsconsfile: "cache_debugging.rb")
+        expect(result.stdout).to match /Target foo\.o needs rebuilding because dependency file simple\.c has changed/
+      end
+    end
   end
 
   context "Object builder" do

spec/rscons/cache_spec.rb

@@ -26,13 +26,13 @@ module Rscons
         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")
+        expect(FileUtils).to receive(:mkdir_p).with("one/two")
         expect(File).to receive(:exists?).with("one/two/three").and_return(false)
-        expect(FileUtils).to receive(:mkdir).with("one/two/three")
+        expect(FileUtils).to receive(:mkdir_p).with("one/two/three")
         expect(File).to receive(:exists?).with("one").and_return(true)
         expect(File).to receive(:exists?).with("one/two").and_return(true)
         expect(File).to receive(:exists?).with("one/two/four").and_return(false)
-        expect(FileUtils).to receive(:mkdir).with("one/two/four")
+        expect(FileUtils).to receive(:mkdir_p).with("one/two/four")
         cache.mkdir_p("one/two/three")
         cache.mkdir_p("one\\two\\four")
         expect(cache.directories).to eq ["one/two", "one/two/three", "one/two/four"]
@@ -43,7 +43,7 @@ module Rscons
         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")
+        expect(FileUtils).to receive(:mkdir_p).with("/one/two")
         cache.mkdir_p("/one/two")
         expect(cache.directories).to eq ["/one/two"]
       end

spec/rscons/environment_spec.rb

@@ -184,7 +184,7 @@ 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("${foo}")}.to raise_error /Unknown.varref.type/
+        expect {env.expand_varref("${foo}")}.to raise_error /Unknown.construction.variable.type/
         expect(env.expand_varref("${specialflag}")).to eq "-z"
         expect(env.expand_varref("${path}")).to eq ["dir1", "dir2"]
       end
@@ -329,7 +329,7 @@ module Rscons
         expect(File).to receive(:read).with('makefile').and_return(<<EOS)
 module.o: source.cc
 EOS
-        expect(Environment.parse_makefile_deps('makefile', 'module.o')).to eq ['source.cc']
+        expect(Environment.parse_makefile_deps('makefile')).to eq ['source.cc']
       end
 
       it 'handles dependencies split across many lines' do
@@ -338,7 +338,7 @@ module.o: module.c \\
   module.h \\
   other.h
 EOS
-        expect(Environment.parse_makefile_deps('makefile', 'module.o')).to eq [
+        expect(Environment.parse_makefile_deps('makefile')).to eq [
           'module.c', 'module.h', 'other.h']
       end
     end

spec/rscons/varset_spec.rb

@@ -159,14 +159,33 @@ module Rscons
       it "calls a lambda with the given lambda arguments" do
         expect(v.expand_varref("${lambda}", [v: "fez"])).to eq("fez--12")
       end
+      it "returns true when passed true" do
+        expect(v.expand_varref(true, :lambda_args)).to eq(true)
+      end
+      it "returns false when passed false" do
+        expect(v.expand_varref(false, :lambda_args)).to eq(false)
+      end
       it "raises an error when given an invalid argument" do
-        expect { v.expand_varref({a: :b}, :lambda_args) }.to raise_error /Unknown varref type: Hash/
+        expect { v.expand_varref({a: :b}, :lambda_args) }.to raise_error /Unknown construction variable type: Hash/
       end
       it "raises an error when an expanded variable is an unexpected type" do
         expect(v).to receive(:[]).at_least(1).times.with("bad").and_return("bad_val")
         expect(v).to receive(:expand_varref).with("bad_val", :lambda_args).and_return({a: :b})
         expect(v).to receive(:expand_varref).and_call_original
-        expect { v.expand_varref("${bad}", :lambda_args) }.to raise_error /I do not know how to expand a variable reference to a Hash/
+        expect { v.expand_varref("${bad}", :lambda_args) }.to raise_error /Unknown construction variable type: Hash/
+      end
+      it "expands symbols within a string outside an array" do
+        v['var'] = :a_symbol
+        expect(v.expand_varref("this is ${var}", :lambda_args)).to eq "this is a_symbol"
+      end
+      it "expands booleans within a string outside an array" do
+        v['var'] = false
+        expect(v.expand_varref("this is ${var}", :lambda_args)).to eq "this is false"
+      end
+      it "expands symbols and booleans in an array" do
+        v['var'] = [:a_symbol, false]
+        expanded = v.expand_varref("this is ${var}", :lambda_args)
+        expect(expanded).to eq(["this is a_symbol", "this is false"])
       end
     end
 
@@ -199,5 +218,14 @@ module Rscons
       end
     end
 
+    describe "#values_at" do
+      it "returns an array of the values associated with the given keys" do
+        v = VarSet.new({"fuz" => "a string", "foo" => 42, "bar" => :baz,
+                        "qax" => [3, 6], "qux" => {a: :b}})
+        expect(v.values_at).to eq []
+        expect(v.values_at(*%w[fuz qux qax])).to eq ["a string", {a: :b}, [3, 6]]
+      end
+    end
+
   end
 end