blazingly fast sass compilation

Gemfile

@@ -10,7 +10,7 @@ gem 'coffee-script'
 gem 'icalendar' # ical files
 gem 'kramdown'
 gem 'rainpress'
-gem 'sass'
+gem 'sassc'
 gem 'typogruby'
 
 # Needed for atom_feed in blogging helper

Gemfile.lock

@@ -81,17 +81,16 @@ GEM
     public_suffix (3.0.3)
     rack (2.0.5)
     rainpress (1.0.1)
+    rake (12.3.1)
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
     ref (2.0.0)
     ruby_dep (1.5.0)
     rubypants (0.7.0)
-    sass (3.5.6)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
+    sassc (2.0.0)
+      ffi (~> 1.9.6)
+      rake
     shellany (0.0.1)
     slow_enumerator_tools (1.1.0)
     terminal-notifier (2.0.0)
@@ -127,7 +126,7 @@ DEPENDENCIES
   nanoc
   pandoc-ruby
   rainpress
-  sass
+  sassc
   terminal-notifier
   terminal-notifier-guard
   therubyracer

Rules

@@ -164,12 +164,12 @@ end
 #
 compile '/assets/scripts/**/*.coffee' do
   filter :coffeescript
-  filter :uglify_js
+  filter :uglify_js if production?
   write ext: 'js'
 end
 
 compile '/assets/scripts/**/*.js' do
-  filter :uglify_js, harmony: true
+  filter :uglify_js, harmony: true if production?
 end
 
 ignore '/assets/stylesheets/includes/**/*'
@@ -177,14 +177,22 @@ ignore '/data/**/*'
 ignore '/node_modules/**/*'
 
 compile '/assets/stylesheets/**/*.scss' do
-  filter :sass, syntax: :scss, style: :compressed
+  sass_opts = {
+    syntax: :scss,
+    load_paths: ['content/assets/stylesheets']
+  }
+  sass_opts[:style] = :compressed if production?
+  filter :sassc, sass_opts
+
   filter :autoprefixer if production?
   write ext: 'css'
 end
 
 compile '/assets/stylesheets/**/*.css' do
+  if production?
     filter :rainpress
-  filter :autoprefixer if production?
+    filter :autoprefixer
+  end
   write ext: 'css'
 end
 

content/assets/stylesheets/main.scss

@@ -1,7 +1,7 @@
 @import "includes/variables";
 
-@import "../../../node_modules/bulma/bulma";
-@import "../../../node_modules/bulma-divider/divider";
+@import "node_modules/bulma/bulma";
+@import "node_modules/bulma-divider/divider";
 
 .nav-right {
   flex: none;

lib/filters/sassc.rb

@@ -0,0 +1,4 @@
+require 'sassc'
+Nanoc::Filter.define(:sassc) do |content, params|
+  SassC::Engine.new(content, params).render
+end