Add an @each directive for iterating over lists.

lib/sass/engine.rb

@@ -14,6 +14,7 @@
 require 'sass/tree/if_node'
 require 'sass/tree/while_node'
 require 'sass/tree/for_node'
+require 'sass/tree/each_node'
 require 'sass/tree/debug_node'
 require 'sass/tree/warn_node'
 require 'sass/tree/import_node'
@@ -610,6 +611,8 @@ def parse_directive(parent, line, root)
         parse_mixin_include(line, root)
       elsif directive == "for"
         parse_for(line, root, value)
+      elsif directive == "each"
+        parse_each(line, root, value)
       elsif directive == "else"
         parse_else(parent, line, value)
       elsif directive == "while"
@@ -671,6 +674,27 @@ def parse_for(line, root, text)
       Tree::ForNode.new(var, parsed_from, parsed_to, to_name == 'to')
     end
 
+    def parse_each(line, root, text)
+      var, list_expr = text.scan(/^([^\s]+)\s+in\s+(.+)$/).first
+
+      if var.nil? # scan failed, try to figure out why for error message
+        if text !~ /^[^\s]+/
+          expected = "variable name"
+        elsif text !~ /^[^\s]+\s+from\s+.+/
+          expected = "'in <expr>'"
+        end
+        raise SyntaxError.new("Invalid for directive '@each #{text}': expected #{expected}.")
+      end
+      raise SyntaxError.new("Invalid variable \"#{var}\".") unless var =~ Script::VALIDATE
+      if var.slice!(0) == ?!
+        offset = line.offset + line.text.index("!" + var) + 1
+        Script.var_warning(var, @line, offset, @options[:filename])
+      end
+
+      parsed_list = parse_script(list_expr, :offset => line.offset + line.text.index(list_expr))
+      Tree::EachNode.new(var, parsed_list)
+    end
+
     def parse_else(parent, line, text)
       previous = parent.children.last
       raise SyntaxError.new("@else must come after @if.") unless previous.is_a?(Tree::IfNode)

lib/sass/scss/parser.rb

@@ -98,8 +98,8 @@ def process_comment(text, node)
         node << comment
       end
 
-      DIRECTIVES = Set[:mixin, :include, :debug, :warn, :for, :while, :if, :extend, :import,
-        :media, :charset]
+      DIRECTIVES = Set[:mixin, :include, :debug, :warn, :for, :each, :while, :if,
+        :extend, :import, :media, :charset]
 
       def directive
         return unless tok(/@/)
@@ -169,6 +169,18 @@ def for_directive
         block(node(Sass::Tree::ForNode.new(var, from, to, exclusive)), :directive)
       end
 
+      def each_directive
+        tok!(/\$/)
+        var = tok! IDENT
+        ss
+
+        tok!(/in/)
+        list = sass_script(:parse)
+        ss
+
+        block(node(Sass::Tree::EachNode.new(var, list)), :directive)
+      end
+
       def while_directive
         expr = sass_script(:parse)
         ss

lib/sass/tree/each_node.rb

@@ -0,0 +1,54 @@
+require 'sass/tree/node'
+
+module Sass::Tree
+  # A dynamic node representing a Sass `@each` loop.
+  #
+  # @see Sass::Tree
+  class EachNode < Node
+    # @param var [String] The name of the loop variable
+    # @param list [Script::Node] The parse tree for the list
+    def initialize(var, list)
+      @var = var
+      @list = list
+      super()
+    end
+
+    protected
+
+    # @see Node#to_src
+    def to_src(tabs, opts, fmt)
+      "#{'  ' * tabs}@each $#{dasherize(@var, opts)} in #{@list.to_sass(opts)}" +
+        children_to_src(tabs, opts, fmt)
+    end
+
+    # Runs the child nodes once for each value in the list.
+    #
+    # @param environment [Sass::Environment] The lexical environment containing
+    #   variable and mixin values
+    # @return [Array<Tree::Node>] The resulting static nodes
+    # @see Sass::Tree
+    def _perform(environment)
+      list = @list.perform(environment)
+
+      children = []
+      environment = Sass::Environment.new(environment)
+      list.to_a.each do |v|
+        environment.set_local_var(@var, v)
+        children += perform_children(environment)
+      end
+      children
+    end
+
+    # Returns an error message if the given child node is invalid,
+    # and false otherwise.
+    #
+    # {ExtendNode}s are valid within {EachNode}s.
+    #
+    # @param child [Tree::Node] A potential child node.
+    # @return [Boolean, String] Whether or not the child node is valid,
+    #   as well as the error message to display if it is invalid
+    def invalid_child?(child)
+      super unless child.is_a?(ExtendNode)
+    end
+  end
+end

test/sass/conversion_test.rb

@@ -675,6 +675,26 @@ def test_if
 SCSS
   end
 
+  def test_each
+    assert_renders <<SASS, <<SCSS
+a
+  @each $number in 1px 2px 3px 4px
+    b: $number
+
+c
+  @each $str in foo, bar, baz, bang
+    d: $str
+SASS
+a {
+  @each $number in 1px 2px 3px 4px {
+    b: $number; } }
+
+c {
+  @each $str in foo, bar, baz, bang {
+    d: $str; } }
+SCSS
+  end
+
   def test_import
     assert_renders <<SASS, <<SCSS
 @import foo

test/sass/engine_test.rb

@@ -1281,6 +1281,29 @@ def test_else
 SASS
   end
 
+  def test_each
+    assert_equal(<<CSS, render(<<SASS))
+a {
+  b: 1px;
+  b: 2px;
+  b: 3px;
+  b: 4px;
+  c: foo;
+  c: bar;
+  c: baz;
+  c: bang;
+  d: blue; }
+CSS
+a
+  @each $number in 1px 2px 3px 4px
+    b: $number
+  @each $str in foo, bar, baz, bang
+    c: $str
+  @each $single in blue
+    d: $single
+SASS
+  end
+
   def test_variable_reassignment
     assert_equal(<<CSS, render(<<SASS))
 a {

test/sass/scss/scss_test.rb

@@ -235,6 +235,33 @@ def test_while_directive
 SCSS
   end
 
+  def test_each_directive
+    assert_equal <<CSS, render(<<SCSS)
+a {
+  b: 1px;
+  b: 2px;
+  b: 3px;
+  b: 4px; }
+
+c {
+  d: foo;
+  d: bar;
+  d: baz;
+  d: bang; }
+CSS
+a {
+  @each $number in 1px 2px 3px 4px {
+    b: $number;
+  }
+}
+c {
+  @each $str in foo, bar, baz, bang {
+    d: $str;
+  }
+}
+SCSS
+  end
+
   def test_css_import_directive
     assert_equal "@import url(foo.css);\n", render('@import "foo.css";')
     assert_equal "@import url(foo.css);\n", render("@import 'foo.css';")