Allow specifying a custom binding for template evaluation

Author: segiddins

lib/thor/actions/file_manipulation.rb

@@ -110,7 +110,7 @@ def template(source, *args, &block)
       destination = args.first || source.sub(/#{TEMPLATE_EXTNAME}$/, "")
 
       source  = File.expand_path(find_in_source_paths(source.to_s))
-      context = instance_eval("binding")
+      context = config.delete(:context) || instance_eval("binding")
 
       create_file destination, nil, config do
         content = ERB.new(::File.binread(source), nil, "-", "@output_buffer").result(context)

spec/actions/file_manipulation_spec.rb

@@ -205,6 +205,16 @@ def file
       expect(File.read(File.join(destination_root, "doc/config.rb"))).to match(/^OMG/)
     end
 
+    it "accepts a context to use as the binding" do
+      begin
+        @klass = 'FooBar'
+        action :template, "doc/config.rb", :context => eval("binding")
+        expect(File.read(File.join(destination_root, "doc/config.rb"))).to eq("class FooBar; end\n")
+      ensure
+        remove_instance_variable(:@klass)
+      end
+    end
+
     it "guesses the destination name when given only a source" do
       action :template, "doc/config.yaml.tt"