Make Ruby Sass the default, but use SassC if available. Addresses #1648

Gemfile

@@ -13,6 +13,7 @@ gem 'cucumber', '~> 2.0', require: false
 
 # Optional middleman dependencies, included for tests
 gem 'haml', '>= 4.0.5', require: false
+gem 'sassc', '~> 1.8'
 gem 'coffee-script', '~> 2.2', require: false
 gem 'kramdown', '~> 1.2', require: false
 gem 'slim', '>= 2.0', require: false

middleman-core/lib/middleman-core/renderers/sass.rb

@@ -1,12 +1,5 @@
 require 'sass'
 
-SASS_MODULE = begin
-  require 'sassc'
-  ::SassC
-rescue LoadError => e
-  ::Sass
-end
-
 module Middleman
   module Renderers
     # Sass renderer
@@ -59,11 +52,17 @@ module Middleman
         def evaluate(context, _)
           @context ||= context
 
-          @engine = SASS_MODULE::Engine.new(data, sass_options)
+          sass_module = if defined?(::SassC)
+            ::SassC
+          else
+            ::Sass
+          end
+
+          @engine = sass_module::Engine.new(data, sass_options)
 
           begin
             @engine.render
-          rescue SASS_MODULE::SyntaxError => e
+          rescue sass_module::SyntaxError => e
             ::Sass::SyntaxError.exception_to_css(e)
           end
         end

middleman-core/lib/middleman-core/renderers/sass_functions.rb

@@ -105,7 +105,13 @@ module Middleman
   end
 end
 
-::SassC::Script::Functions.send :include, ::Middleman::Sass::Functions
+SASS_MODULE = if defined?(::SassC)
+  ::SassC
+else
+  ::Sass
+end
+
+SASS_MODULE::Script::Functions.send :include, ::Middleman::Sass::Functions
 
 # module SASS_MODULE::Script::Functions
 #   include ::Middleman::Sass::Functions

middleman-core/middleman-core.gemspec

@@ -42,7 +42,7 @@ Gem::Specification.new do |s|
   s.add_dependency('fastimage', ['~> 1.7.0'])
 
   # Minify CSS
-  s.add_dependency('sassc', ['>= 1.6.0'])
+  s.add_dependency('sass', ['>= 3.4'])
 
   # Minify JS
   s.add_dependency('uglifier', ['~> 2.6'])