Implement css filter

lib/hamlit/compilers/filter.rb

@@ -1,5 +1,6 @@
 require 'hamlit/concerns/included'
 require 'hamlit/concerns/registerable'
+require 'hamlit/filters/css'
 require 'hamlit/filters/escaped'
 require 'hamlit/filters/plain'
 require 'hamlit/filters/preserve'
@@ -12,6 +13,7 @@ module Hamlit
       included do
         extend Concerns::Registerable
 
+        register :css,      Filters::Css
         register :escaped,  Filters::Escaped
         register :plain,    Filters::Plain
         register :preserve, Filters::Preserve

lib/hamlit/filters/css.rb

@@ -0,0 +1,31 @@
+module Hamlit
+  module Filters
+    class Css
+      def compile(lines)
+        ast = [:haml, :text, compile_lines(lines, indent_width: 2)]
+        ast = [:multi, [:static, "\n"], ast]
+        ast = [:html, :tag, 'style', [:html, :attrs], ast]
+        ast
+      end
+
+      private
+
+      def compile_lines(lines, indent_width: 0)
+        text = strip_last(lines).map { |line|
+          ' ' * indent_width + line
+        }.join("\n")
+        text += "\n" if text.length > 0
+        text
+      end
+
+      # NOTE: empty line is reserved for preserve filter.
+      def strip_last(lines)
+        lines = lines.dup
+        while lines.last && lines.last.length == 0
+          lines.delete_at(-1)
+        end
+        lines
+      end
+    end
+  end
+end

spec/hamlit/filters/css_spec.rb

@@ -1,33 +1,33 @@
-# describe Hamlit::Filters::Css do
-#   describe '#compile' do
-#     it 'renders css' do
-#       assert_render(<<-HAML, <<-HTML)
-#         :css
-#           .foo {
-#             width: 100px;
-#           }
-#       HAML
-#         <style>
-#           .foo {
-#             width: 100px;
-#           }
-#         </style>
-#       HTML
-#     end
-#
-#     it 'parses string interpolation' do
-#       assert_render(<<-'HAML', <<-HTML)
-#         :css
-#           .foo {
-#             width: #{100 * 3}px;
-#           }
-#       HAML
-#         <style>
-#           .foo {
-#             width: 300px;
-#           }
-#         </style>
-#       HTML
-#     end
-#   end
-# end
+describe Hamlit::Filters::Css do
+  describe '#compile' do
+    it 'renders css' do
+      assert_render(<<-HAML, <<-HTML)
+        :css
+          .foo {
+            width: 100px;
+          }
+      HAML
+        <style>
+          .foo {
+            width: 100px;
+          }
+        </style>
+      HTML
+    end
+
+    it 'parses string interpolation' do
+      assert_render(<<-'HAML', <<-HTML)
+        :css
+          .foo {
+            width: #{100 * 3}px;
+          }
+      HAML
+        <style>
+          .foo {
+            width: 300px;
+          }
+        </style>
+      HTML
+    end
+  end
+end