Add support for lists in functions.

lib/sassc/native/native_functions_api.rb

@@ -26,7 +26,10 @@ module Native
 
     # ADDAPI union Sass_Value* ADDCALL sass_make_map     (size_t len);
     attach_function :sass_make_map, [:size_t], :sass_value_ptr
-
+
+    # ADDAPI union Sass_Value* ADDCALL sass_make_list     (size_t len, enum Sass_Separator sep)
+    attach_function :sass_make_list, [:size_t, SassSeparator], :sass_value_ptr
+
     # ADDAPI union Sass_Value* ADDCALL sass_make_boolean (boolean val);
     attach_function :sass_make_boolean, [:bool], :sass_value_ptr
 
@@ -45,6 +48,15 @@ module Native
     # ADDAPI size_t ADDCALL sass_map_get_length (const union Sass_Value* v);
     attach_function :sass_map_get_length, [:sass_value_ptr], :size_t
 
+    # ADDAPI union Sass_Value* ADDCALL sass_list_get_value (const union Sass_Value* v, size_t i);
+    attach_function :sass_list_get_value, [:sass_value_ptr, :size_t], :sass_value_ptr
+
+    # ADDAPI void ADDCALL sass_list_set_value (union Sass_Value* v, size_t i, union Sass_Value* value);
+    attach_function :sass_list_set_value, [:sass_value_ptr, :size_t, :sass_value_ptr], :void
+
+    # ADDAPI size_t ADDCALL sass_list_get_length (const union Sass_Value* v);
+    attach_function :sass_list_get_length, [:sass_value_ptr], :size_t
+
     # ADDAPI union Sass_Value* ADDCALL sass_make_error   (const char* msg);
     attach_function :sass_make_error, [:string], :sass_value_ptr
 

lib/sassc/script/value_conversion.rb

@@ -41,6 +41,13 @@ def self.from_native(native_value, options)
 
           argument = Sass::Script::Value::Map.new values
           argument
+        when :sass_list
+          length = Native::list_get_length(native_value)
+          items = (0...length).map do |index|
+            native_item = Native::list_get_value(native_value, index)
+            from_native(native_item, options)
+          end
+          Sass::Script::Value::List.new(items, :space)
         else
           raise UnsupportedValue.new("Sass argument of type #{value_tag} unsupported")
         end
@@ -56,6 +63,8 @@ def self.to_native(value)
           Number.new(value).to_native
         when "Map"
           Map.new(value).to_native
+        when "List"
+          List.new(value).to_native
         when "Bool"
           Bool.new(value).to_native
         else
@@ -71,4 +80,5 @@ def self.to_native(value)
 require_relative "value_conversion/number"
 require_relative "value_conversion/color"
 require_relative "value_conversion/map"
-require_relative "value_conversion/bool"
+require_relative "value_conversion/list"
+require_relative "value_conversion/bool"

lib/sassc/script/value_conversion/list.rb

@@ -0,0 +1,23 @@
+module SassC
+  module Script
+    module ValueConversion
+      SEPARATORS = {
+        space: :sass_space,
+        comma: :sass_comma
+      }
+
+      class List < Base
+        def to_native
+          list = @value.to_a
+          sep = SEPARATORS.fetch(@value.separator)
+          native_list = Native::make_list(list.size, sep)
+          list.each_with_index do |item, index|
+            native_item = ValueConversion.to_native(item)
+            Native::list_set_value(native_list, index, native_item)
+          end
+          native_list
+        end
+      end
+    end
+  end
+end

test/functions_test.rb

@@ -119,6 +119,7 @@ def test_functions_may_accept_sass_color_type
     end
 
     def test_function_with_unsupported_tag
+      skip('What are other unsupported tags?')
       engine = Engine.new("div {url: function_with_unsupported_tag(());}")
 
       exception = assert_raises(SassC::SyntaxError) do
@@ -166,6 +167,23 @@ def test_function_that_takes_a_sass_map
       CSS
     end
 
+    def test_function_that_returns_a_sass_list
+      assert_sass <<-SCSS, <<-CSS
+        $my-list: returns-sass-list();
+        div { width: nth( $my-list, 2 ); }
+      SCSS
+        div { width: 20; }
+      CSS
+    end
+
+    def test_function_that_takes_a_sass_list
+      assert_sass <<-SCSS, <<-CSS
+        div { width: nth(inspect-list((10 20 30)), 2); }
+      SCSS
+        div { width: 20; }
+      CSS
+    end
+
     private
 
     def assert_sass(sass, expected_css)
@@ -250,6 +268,11 @@ def inspect_map ( argument )
         return argument
       end
 
+      def inspect_list(argument)
+        raise StandardError.new "passed value is not a Sass::Script::Value::List" unless argument.is_a? Sass::Script::Value::List
+        return argument
+      end
+
       def returns_sass_value
         return Sass::Script::Value::Color.new(red: 0, green: 0, blue: 0)
       end
@@ -263,6 +286,13 @@ def returns_sass_map
         return map
       end
 
+      def returns_sass_list
+        numbers = [10, 20, 30].map do |n|
+          Sass::Script::Value::Number.new(n, '')
+        end
+        Sass::Script::Value::List.new(numbers, :space)
+      end
+
       module Compass
         def stylesheet_path(path)
           Script::String.new("/css/#{path.value}", :identifier)