From 39265bafc3b500166e1584806cb4cff212d7aafa Mon Sep 17 00:00:00 2001
From: Chris Eppstein <chris@eppsteins.net>
Date: Sat, 29 Nov 2008 01:08:07 -0800
Subject: [PATCH] Added a Sass Function called nest that performs a nesting
 operation on (possibly) comma delimited selectors and emits the result as a
 string. For example:

nest(".foo", "a, em, b")

would render:

.foo a, .foo em, .foo b

The nest function can take any number of arguments and each argument can have any number of comma-delimited selectors.
---
 Rakefile                     |  4 ++--
 lib/compass.rb               |  3 +++
 lib/sass_extensions.rb       | 13 +++++++++++++
 test/sass_extensions_test.rb | 26 ++++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 lib/sass_extensions.rb
 create mode 100644 test/sass_extensions_test.rb

diff --git a/Rakefile b/Rakefile
index 6ffa272f..7c12d031 100644
--- a/Rakefile
+++ b/Rakefile
@@ -4,12 +4,12 @@ require 'lib/compass'
 
 # ----- Default: Testing ------
 
-task :default => :tests
+task :default => :run_tests
 
 require 'rake/testtask'
 require 'fileutils'
 
-Rake::TestTask.new :test do |t|
+Rake::TestTask.new :run_tests do |t|
   t.libs << 'lib'
   test_files = FileList['test/**/*_test.rb']
   test_files.exclude('test/rails/*', 'test/haml/*')
diff --git a/lib/compass.rb b/lib/compass.rb
index 285afdc8..683a9502 100644
--- a/lib/compass.rb
+++ b/lib/compass.rb
@@ -1,3 +1,6 @@
+require 'sass'
+require File.join(File.dirname(__FILE__), 'sass_extensions')
+
 ['core_ext', 'version'].each do |file|
   require File.join(File.dirname(__FILE__), 'compass', file)
 end
diff --git a/lib/sass_extensions.rb b/lib/sass_extensions.rb
new file mode 100644
index 00000000..d432d818
--- /dev/null
+++ b/lib/sass_extensions.rb
@@ -0,0 +1,13 @@
+require 'sass'
+
+module Sass::Script::Functions
+  COMMA_SEPARATOR = /\s*,\s*/
+  def nest(*arguments)
+    nested = arguments.map{|a| a.value}.inject do |memo,arg|
+      ancestors = memo.split(COMMA_SEPARATOR)
+      descendants = arg.split(COMMA_SEPARATOR)
+      ancestors.map{|a| descendants.map{|d| "#{a} #{d}"}.join(", ")}.join(", ")
+    end
+    Sass::Script::String.new(nested)
+  end
+end
\ No newline at end of file
diff --git a/test/sass_extensions_test.rb b/test/sass_extensions_test.rb
new file mode 100644
index 00000000..7d59748a
--- /dev/null
+++ b/test/sass_extensions_test.rb
@@ -0,0 +1,26 @@
+require  File.dirname(__FILE__)+'/test_helper'
+require 'compass'
+
+class SassExtensionsTest < Test::Unit::TestCase
+  def test_simple
+    assert_equal "a b", nest("a", "b")
+  end
+  def test_left_side_expansion
+    assert_equal "a c, b c", nest("a, b", "c")
+  end
+  def test_right_side_expansion
+    assert_equal "a b, a c", nest("a", "b, c")
+  end
+  def test_both_sides_expansion
+    assert_equal "a c, a d, b c, b d", nest("a, b", "c, d")
+  end
+  def test_three_selectors_expansion
+    assert_equal "a b, a c, a d", nest("a", "b, c, d")
+  end
+  def test_third_argument_expansion
+    assert_equal "a b e, a b f, a c e, a c f, a d e, a d f", nest("a", "b, c, d", "e, f")
+  end
+  def nest(*arguments)
+    Sass::Script::Functions.nest(*arguments.map{|a| Sass::Script::String.new(a)}).to_s
+  end
+end
\ No newline at end of file