From 5ff555cf6a55549d0b0797c5620a6d90c6fc9908 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Thu, 2 Jan 2014 11:49:08 -0500
Subject: [PATCH] add Environment#expand_varref()

---
 lib/rscons/environment.rb       |  5 +++++
 spec/rscons/environment_spec.rb | 14 ++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/rscons/environment.rb b/lib/rscons/environment.rb
index 871e1ea..16dfdb6 100644
--- a/lib/rscons/environment.rb
+++ b/lib/rscons/environment.rb
@@ -185,6 +185,11 @@ module Rscons
       @varset.merge(extra_vars).expand_varref(command_template)
     end
 
+    # Expand a construction variable reference (String or Array)
+    def expand_varref(varref)
+      @varset.expand_varref(varref)
+    end
+
     # Execute a builder command
     # @param short_desc [String] Message to print if the Environment's echo
     #   mode is set to :short
diff --git a/spec/rscons/environment_spec.rb b/spec/rscons/environment_spec.rb
index 03ad1d3..47d7c23 100644
--- a/spec/rscons/environment_spec.rb
+++ b/spec/rscons/environment_spec.rb
@@ -199,6 +199,20 @@ module Rscons
       end
     end
 
+    describe "#expand_varref" do
+      it "returns the fully expanded variable reference" do
+        env = Environment.new
+        env["path"] = ["dir1", "dir2"]
+        env["flags"] = ["-x", "-y", "${specialflag}"]
+        env["specialflag"] = "-z"
+        env.expand_varref(["-p${path}", "${flags}"]).should == ["-pdir1", "-pdir2", "-x", "-y", "-z"]
+        env.expand_varref("foo").should == "foo"
+        expect {env.expand_varref("${foo}")}.to raise_error /expand.a.variable.reference/
+        env.expand_varref("${specialflag}").should == "-z"
+        env.expand_varref("${path}").should == ["dir1", "dir2"]
+      end
+    end
+
     describe "#execute" do
       context "with echo: :short" do
         context "with no errors" do