[Sass] Add support for single-quoted strings.

doc-src/SASS_CHANGELOG.md

@@ -29,6 +29,13 @@ For example:
 
     !prettiest-color = #542FA9
 
+### Single-Quoted Strings
+
+SassScript now supports single-quoted strings.
+They behave identically to double-quoted strings,
+except that single quotes need to be backslash-escaped
+and double quotes do not.
+
 ### Error Backtraces
 
 Numerous bugs were fixed with the backtraces given for Sass errors,

doc-src/SASS_REFERENCE.md

@@ -691,7 +691,7 @@ available in that context.
 
 SassScript supports four data types:
 * numbers (e.g. `1.2`, `13`, `10px`)
-* strings of text (e.g. `"foo"`, `"bar"`)
+* strings of text (e.g. `"foo"`, `"bar"`, `'baz'`)
 * colors (e.g. `blue`, `#04a3f9`, `rgba(255, 0, 0, 0.5)`)
 * booleans (e.g. `true`, `false`)
 

lib/sass/script/lexer.rb

@@ -54,13 +54,32 @@ module Sass
         :whitespace => /\s*/,
         :variable => /!([\w-]+)/,
         :ident => /(\\.|[^\s\\+*\/%(),=!])+/,
-        :string_end => /((?:\\.|\#(?!\{)|[^"\\#])*)(?:"|(?=#\{))/,
         :number => /(-)?(?:(\d*\.\d+)|(\d+))([a-zA-Z%]+)?/,
         :color => /\##{"([0-9a-fA-F]{1,2})" * 3}|(#{Color::HTML4_COLORS.keys.join("|")})(?!\()/,
         :bool => /(true|false)\b/,
         :op => %r{(#{Regexp.union(*OP_NAMES.map{|s| Regexp.new(Regexp.escape(s) + (s =~ /\w$/ ? '(?:\b|$)' : ''))})})}
       }
 
+      class << self
+        private
+        def string_re(open, close)
+          /#{open}((?:\\.|\#(?!\{)|[^#{close}\\#])*)(#{close}|(?=#\{))/
+        end
+      end
+
+      # A hash of regular expressions that are used for tokenizing strings.
+      #
+      # The key is a [Symbol, Boolean] pair.
+      # The symbol represents which style of quotation to use,
+      # while the boolean represents whether or not the string
+      # is following an interpolated segment.
+      STRING_REGULAR_EXPRESSIONS = {
+        [:double, false] => string_re('"', '"'),
+        [:single, false] => string_re("'", "'"),
+        [:double, true] => string_re('', '"'),
+        [:single, true] => string_re('', "'"),
+      }
+
       # @param str [String, StringScanner] The source text to lex
       # @param line [Fixnum] The line on which the SassScript appears.
       #   Used for error reporting
@@ -71,6 +90,7 @@ module Sass
         @line = line
         @offset = offset
         @filename = filename
+        @interpolation_stack = []
         @prev = nil
       end
 
@@ -114,8 +134,8 @@ module Sass
       end
 
       def token
-        return string('') if after_interpolation?
-        variable || string || number || color || bool || op || ident
+        return string(@interpolation_stack.pop, true) if after_interpolation?
+        variable || string(:double, false) || string(:single, false) || number || color || bool || op || ident
       end
 
       def variable
@@ -128,8 +148,9 @@ module Sass
         [:ident, s.gsub(/\\(.)/, '\1')]
       end
 
-      def string(start_char = '"')
-        return unless @scanner.scan(/#{start_char}#{REGULAR_EXPRESSIONS[:string_end]}/)
+      def string(re, open)
+        return unless @scanner.scan(STRING_REGULAR_EXPRESSIONS[[re, open]])
+        @interpolation_stack << re if @scanner[2].empty? # Started an interpolated section
         [:string, Script::String.new(@scanner[1].gsub(/\\([^0-9a-f])/, '\1').gsub(/\\([0-9a-f]{1,4})/, "\\\\\\1"))]
       end
 

test/sass/script_test.rb

@@ -16,9 +16,21 @@ class SassScriptTest < Test::Unit::TestCase
   end
 
   def test_string_escapes
+    assert_equal "'", resolve("\"'\"")
     assert_equal '"', resolve("\"\\\"\"")
     assert_equal "\\", resolve("\"\\\\\"")
     assert_equal "\\02fa", resolve("\"\\02fa\"")
+
+    assert_equal "'", resolve("'\\''")
+    assert_equal '"', resolve("'\"'")
+    assert_equal "\\", resolve("'\\\\'")
+    assert_equal "\\02fa", resolve("'\\02fa'")
+  end
+
+  def test_string_interpolation
+    assert_equal "foo2bar", resolve('\'foo#{1 + 1}bar\'')
+    assert_equal "foo2bar", resolve('"foo#{1 + 1}bar"')
+    assert_equal "foo1bar5baz4bang", resolve('\'foo#{1 + "bar#{2 + 3}baz" + 4}bang\'')
   end
 
   def test_color_names
@@ -188,16 +200,16 @@ WARN
   def test_string_ops
     assert_equal "foo bar", resolve('"foo" "bar"')
     assert_equal "true 1", resolve('true 1')
-    assert_equal "foo, bar", resolve('"foo" , "bar"')
+    assert_equal "foo, bar", resolve("'foo' , 'bar'")
     assert_equal "true, 1", resolve('true , 1')
     assert_equal "foobar", resolve('"foo" + "bar"')
     assert_equal "true1", resolve('true + 1')
-    assert_equal "foo-bar", resolve('"foo" - "bar"')
+    assert_equal "foo-bar", resolve("'foo' - 'bar'")
     assert_equal "true-1", resolve('true - 1')
     assert_equal "foo/bar", resolve('"foo" / "bar"')
     assert_equal "true/1", resolve('true / 1')
 
-    assert_equal "-bar", resolve('- "bar"')
+    assert_equal "-bar", resolve("- 'bar'")
     assert_equal "-true", resolve('- true')
     assert_equal "/bar", resolve('/ "bar"')
     assert_equal "/true", resolve('/ true')