[Sass] [SCSS] Print to-SCSS and to-Sass comments as adjacent to their rules/mixins if they were in the source.

lib/haml/exec.rb

@@ -288,7 +288,7 @@ END
 
           input.close() if input.is_a?(File)
 
-          output.write(tree.render)
+          output.write(tree.to_scss)
           output.close() if output.is_a? File
         rescue ::Sass::SyntaxError => e
           raise e if @options[:trace]

lib/haml/util.rb

@@ -311,6 +311,15 @@ MSG
       ruby1_8? ? enum.enum_with_index : enum.each_with_index
     end
 
+    # A version of `Enumerable#enum_cons` that works in Ruby 1.8 and 1.9.
+    #
+    # @param enum [Enumerable] The enumerable to get the enumerator for
+    # @param n [Fixnum] The size of each cons
+    # @return [Enumerator] The consed enumerator
+    def enum_cons(enum, n)
+      ruby1_8? ? enum.enum_cons(n) : enum.each_cons(n)
+    end
+
     ## Static Method Stuff
 
     # The context in which the ERB for \{#def\_static\_method} will be run.

lib/sass/scss/parser.rb

@@ -75,7 +75,9 @@ module Sass
           reverse[/.*?\*\/(.*?)($|\Z)/, 1].
           reverse.gsub(/[^\s]/, ' ')
         text = text.sub(/^\s*\/\//, '/*').gsub(/^\s*\/\//, ' *') + ' */' if single_line
-        node << Sass::Tree::CommentNode.new(pre_str + text, single_line)
+        comment = Sass::Tree::CommentNode.new(pre_str + text, single_line)
+        comment.line = @line - text.count("\n")
+        node << comment
       end
 
       DIRECTIVES = Set[:mixin, :include, :debug, :for, :while, :if, :import, :media]

lib/sass/tree/root_node.rb

@@ -49,7 +49,7 @@ module Sass
       # @param opts [{Symbol => Object}] An options hash (see {Sass::CSS#initialize})
       # @return [String] The Sass code corresponding to the node
       def to_sass(opts = {})
-        children.map {|child| child.to_sass(0, opts) + "\n"}.join.rstrip + "\n"
+        to_src(opts, :sass)
       end
 
       # Converts a node to SCSS code that will generate it.
@@ -57,11 +57,23 @@ module Sass
       # @param opts [{Symbol => Object}] An options hash (see {Sass::CSS#initialize})
       # @return [String] The SCSS code corresponding to the node
       def to_scss(opts = {})
-        children.map {|child| child.to_scss(0, opts) + "\n"}.join.rstrip + "\n"
+        to_src(opts, :scss)
       end
 
       protected
 
+      def to_src(opts, fmt)
+        Haml::Util.enum_cons(children + [nil], 2).map do |child, nxt|
+          child.send("to_#{fmt}", 0, opts) +
+            if nxt && child.is_a?(CommentNode) &&
+                child.line + child.value.count("\n") + 1 == nxt.line
+              ""
+            else
+              "\n"
+            end
+        end.join.rstrip + "\n"
+      end
+
       # Destructively converts this static Sass node into a static CSS node,
       # and checks that there are no properties at root level.
       #

test/haml/util_test.rb

@@ -95,6 +95,11 @@ class UtilTest < Test::Unit::TestCase
       enum_with_index(%w[foo bar baz]).map {|s, i| "#{s}#{i}"})
   end
 
+  def test_enum_cons
+    assert_equal(%w[foobar barbaz],
+      enum_cons(%w[foo bar baz], 2).map {|s1, s2| "#{s1}#{s2}"})
+  end
+
   def test_caller_info
     assert_equal(["/tmp/foo.rb", 12, "fizzle"], caller_info("/tmp/foo.rb:12: in `fizzle'"))
     assert_equal(["/tmp/foo.rb", 12, nil], caller_info("/tmp/foo.rb:12"))

test/sass/conversion_test.rb

@@ -370,6 +370,36 @@ foo
 SASS
   end
 
+  def test_immediately_preceding_comments
+    assert_renders <<SASS, <<SCSS
+/* Foo
+   Bar
+   Baz
+.foo#bar
+  a: b
+SASS
+/* Foo
+ * Bar
+ * Baz */
+.foo#bar {
+  a: b; }
+SCSS
+
+    assert_renders <<SASS, <<SCSS
+// Foo
+   Bar
+   Baz
+=foo
+  a: b
+SASS
+// Foo
+// Bar
+// Baz
+@mixin foo {
+  a: b; }
+SCSS
+  end
+
   def test_debug
     assert_renders <<SASS, <<SCSS
 foo