Map literals in Parsley, and a few other minor fixes.parsley

- Labels for some of the rules.
- Faux goal_argspec rule to play nicely with parse_expression.
- Wrap ParseErrors in SassParseError.
- Ruby's interp-and-slash test now passes exactly.
- Don't render nulls in an interpolation.

3 files changed, 28 insertions, 7 deletions

diff --git a/scss/expression.parsley b/scss/expression.parsley
index 77b41fa..8fc35bf 100644
--- a/scss/expression.parsley
+++ b/scss/expression.parsley
@@ -38,7 +38,7 @@ spaced_list = single_expression:head (
     )*:tails -> ListLiteral([head] + tails, comma=False) if tails else head
 
 
-single_expression = or_test
+single_expression = or_test  ^(single expression)
 
 or_test = and_test:head (
         'o' 'r'
@@ -97,6 +97,9 @@ atom = (
         # TODO kill this off
         | '[' comma_list:node ']' -> Parentheses(node)
 
+        # Map literal
+        | map
+
         # URL literal
         | 'u' 'r' 'l' '(' inside_url:s ')' -> FunctionLiteral('url', s)
 
@@ -135,6 +138,21 @@ atom = (
         # Variable
         | variable:name -> Variable(name)
     )
+    ^(single value)
+
+
+### Map literals
+map = '(' ows
+    ( map_pair:pair ows ',' ows -> pair )*:pairs
+    ( map_pair:pair ows !(pairs.append(pair)) )?
+    ')'
+    -> MapLiteral(pairs)
+
+map_pair =
+    single_expression:key
+    ows ':' ows
+    spaced_list:value
+    -> (key, value)
 
 
 ### Strings, literals, and interpolation
@@ -174,6 +192,8 @@ string_part :end = <(
 
 
 ### Function definitions and arguments
+goal_argspec = argspec
+
 argspec = (
         argspec_item:node
         ows ',' ows
@@ -186,7 +206,7 @@ argspec = (
 argspec_item =
     ows
     (
-        ( variable:name ows ':' ows -> name )?:name
+        ( variable:name ows ':' ows -> Variable(name) )?:name
         spaced_list:value
         -> (name, value)
     )
diff --git a/scss/expression.py b/scss/expression.py
index ebec7e2..bd19031 100644
--- a/scss/expression.py
+++ b/scss/expression.py
@@ -29,7 +29,7 @@ log = logging.getLogger(__name__)
 FATAL_UNDEFINED = True
 
 
-from ometa.runtime import EOFError, OMetaBase, expected
+from ometa.runtime import EOFError, OMetaBase, ParseError, expected
 import string
 HEXDIGITS = frozenset(string.hexdigits)
 WHITESPACE = frozenset(' \n\r\t\f')
@@ -224,7 +224,7 @@ class Calculator(object):
 
             ast = getattr(parser, target)()
             print(repr(ast))
-        except SyntaxError as e:
+        except (SyntaxError, ParseError) as e:
             raise SassParseError(e, expression=expr, expression_pos=parser._char_pos)
 
         self.ast_cache[key] = ast
@@ -551,7 +551,9 @@ class Interpolation(Expression):
         ret = []
         for part in self.parts:
             expr = part.evaluate(calculator)
-            if isinstance(expr, String):
+            if expr.is_null:
+                pass
+            elif isinstance(expr, String):
                 ret.append(expr.value)
             else:
                 ret.append(expr.render())
diff --git a/scss/tests/test_expression.py b/scss/tests/test_expression.py
index a16950e..848d9ce 100644
--- a/scss/tests/test_expression.py
+++ b/scss/tests/test_expression.py
@@ -43,8 +43,7 @@ def test_reference_operations():
     assert calc('$width/2') == Number(500, "px")      # uses a variable; does division
     assert calc('(500px/2)') == Number(250, "px")     # uses parens; does division
     assert calc('5px + 8px/2px') == Number(9, "px")   # uses +; does division
-    # TODO: Ruby doesn't include these spaces
-    assert calc('#{$font-size}/#{$line-height}') == String('12px / 30px')
+    assert calc('#{$font-size}/#{$line-height}') == String('12px/30px')
                                             # uses #{}; does no division
 
     # Color operations