[Sass] [css2sass] Automatically backslash-escape pseudo-classes.

Closes gh-51

doc-src/SASS_CHANGELOG.md

@@ -12,6 +12,8 @@
   if {file:SASS_REFERENCE.md.html#property_syntax-option `:property_syntax`}
   is set to `:new`.
 
+* Fixed `css2sass`'s generation of pseudo-classes so that they're backslash-escaped.
+
 ## [2.2.10](http://github.com/nex3/haml/commit/2.2.10)
 
 * Add support for attribute selectors with spaces around the `=`.

lib/sass/css.rb

@@ -24,7 +24,9 @@ module Sass
     class RuleNode
       # @see Node#to_sass
       def to_sass(tabs, opts = {})
-        str = "\n#{'  ' * tabs}#{rules.first}#{children.any? { |c| c.is_a? PropNode } ? "\n" : ''}"
+        name = rules.first
+        name = "\\" + name if name[0] == ?:
+        str = "\n#{'  ' * tabs}#{name}#{children.any? { |c| c.is_a? PropNode } ? "\n" : ''}"
 
         children.each do |child|
           str << "#{child.to_sass(tabs + 1, opts)}"

test/sass/css2sass_test.rb

@@ -230,6 +230,19 @@ SASS
 CSS
   end
 
+  def test_pseudo_classes_are_escaped
+    assert_equal(<<SASS, css2sass(<<CSS))
+\\:focus
+  a: b
+
+  \\:foo
+    bar: baz
+SASS
+:focus {a: b;}
+:focus :foo {bar: baz;}
+CSS
+  end
+
   private
 
   def css2sass(string, opts={})