Implements the beginning of the background parser/transformer

Still needs some work

Author: zmoazeni

lib/csscss.rb

@@ -14,3 +14,4 @@
 
 require "csscss/parser/common"
 require "csscss/parser/color"
+require "csscss/parser/background"

lib/csscss/parser/background.rb

@@ -0,0 +1,50 @@
+module Csscss
+  module Parser
+    module Background
+      class Parser < Parslet::Parser
+        include Color
+
+        #rule(:background_color) { (color | symbol("inherit")).as(:bg_color) }
+        #rule(:background_url) { (url | symbol("none") | symbol("inherit")).as(:bg_url) }
+
+        rule(:background_color) { color | symbol("inherit") }
+        rule(:background_image) { url | (symbol("none") | symbol("inherit")).as(:image_literal) }
+
+        rule(:background) {
+          (background_color.maybe.as(:bg_color) >> background_image.maybe.as(:bg_image)).as(:background)
+        }
+        root(:background)
+      end
+
+      class Transformer < Parslet::Transform
+        rule(rgb:{
+          red:{percent:simple(:red)},
+          green:{percent:simple(:green)},
+          blue:{percent:simple(:blue)}
+        }) { {rgb:{red:"#{red}%", green:"#{green}%", blue:"#{blue}%"}}}
+
+        rule(color:{rgb:subtree(:rgb)}) {
+          "background-color: rgb(#{rgb[:red]}, #{rgb[:green]}, #{rgb[:blue]})"
+        }
+
+        rule(color:{keyword:simple(:keyword)}) {
+          "background-color: #{keyword.to_s.downcase}".strip
+        }
+
+        rule(color:{hexcolor:simple(:value)}) {
+          "background-color: ##{value}"
+        }
+
+        rule(image_literal:simple(:url)) {"background-image: #{url}"}
+        rule(url:simple(:url)) {"background-image: #{url}"}
+
+        rule(background: {
+          bg_color:simple(:color),
+          bg_image: simple(:url)
+        }) {
+          [color, url].compact
+        }
+      end
+    end
+  end
+end

test/csscss/parser/background_test.rb

@@ -0,0 +1,31 @@
+require "test_helper"
+
+module Csscss::Parser
+  module Background
+    describe Background do
+      before do
+        @parser = Parser.new
+        @trans = Transformer.new
+      end
+
+      def trans(s)
+        @trans.apply(@parser.parse(s))
+      end
+
+      it "converts color to shorthand" do
+        trans("#fff").must_equal(["background-color: #fff"])
+        trans("BLACK").must_equal(["background-color: black"])
+        trans("inherit").must_equal(["background-color: inherit"])
+        trans("inherit none").must_equal([
+          "background-color: inherit",
+          "background-image: none"
+        ])
+
+        trans("#fff url(http://foo.com/bar.jpg)").must_equal([
+          "background-color: #fff",
+          "background-image: url(http://foo.com/bar.jpg)"
+        ])
+      end
+    end
+  end
+end