Add PATH manipulation methods - close #126

build_tests/simple/path_append/foobar

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+echo "foobar!"

build_tests/simple/path_append/gcc

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exit 42

build_tests/simple/path_prepend/flex

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+echo "flex!"

build_tests/simple/pathing.rb

@@ -0,0 +1,10 @@
+path_prepend "path_prepend"
+path_append "path_append"
+
+build do
+  Environment.new do |env|
+    system("flex")
+    system("foobar")
+    env.Object("simple.o", "simple.c")
+  end
+end

doc/user_guide.md

@@ -932,6 +932,22 @@ subsidiary build script.
 Subsidiary build scripts are executed from within the directory containing the
 build script.
 
+###> PATH Management
+
+`rscons` provides methods for management of the `PATH` environment variable.
+
+The `path_append` and `path_prepend` methods can be used to append or prepend
+a path to the `PATH` environment variable.
+
+```ruby
+path_prepend "i686-elf-gcc/bin"
+```
+
+The `path_set` method sets the `PATH` environment variable to the given
+Array or String.
+The `path_components` method returns an Array of the components in the `PATH`
+environment variable.
+
 ##> Extending Rscons
 
 ### Adding New Languages

lib/rscons/script.rb

@@ -6,6 +6,47 @@ module Rscons
     # Global DSL methods.
     class GlobalDsl
 
+      # Return path components from the PATH variable.
+      #
+      # @return [Array<String>]
+      #   Path components from the PATH variable.
+      def path_components
+        ENV["PATH"].split(File::PATH_SEPARATOR)
+      end
+
+      # Prepend a path component to the PATH variable.
+      #
+      # @param path [String]
+      #   Path to prepend.
+      #
+      # @return [void]
+      def path_prepend(path)
+        path_set([File.expand_path(path)] + path_components)
+      end
+
+      # Append a path component to the PATH variable.
+      #
+      # @param path [String]
+      #   Path to append.
+      #
+      # @return [void]
+      def path_append(path)
+        path_set(path_components + [File.expand_path(path)])
+      end
+
+      # Set the PATH variable.
+      #
+      # @param new_path [String, Array<String>]
+      #   New PATH variable value as an array or string.
+      #
+      # @return [void]
+      def path_set(new_path)
+        if new_path.is_a?(Array)
+          new_path = new_path.join(File::PATH_SEPARATOR)
+        end
+        ENV["PATH"] = new_path
+      end
+
       # Invoke rscons in a subprocess for a subsidiary Rsconscript file.
       #
       # @param path [String]

spec/build_tests_spec.rb

@@ -1475,6 +1475,15 @@ EOF
       expect(result.status).to eq 0
     end
 
+    it "allows prepending and appending to PATH" do
+      test_dir "simple"
+      result = run_rscons(rsconscript: "pathing.rb")
+      expect(result.stderr).to eq ""
+      expect(result.stdout).to match /flex!/
+      expect(result.stdout).to match /foobar!/
+      expect(File.exist?("simple.o")).to be_truthy
+    end
+
     context "debugging" do
       it "prints a message when the target does not exist" do
         test_dir("simple")