Understand (and correctly ignore) IE's expression() function.

3 files changed, 80 insertions, 25 deletions

diff --git a/scss/ast.py b/scss/ast.py
index b1bc77d..fb64f85 100644
--- a/scss/ast.py
+++ b/scss/ast.py
@@ -214,24 +214,25 @@ class Interpolation(Expression):
 
         foo#{...}bar#{...}baz
     """
-    def __init__(self, parts, quotes=None, type=String):
+    def __init__(self, parts, quotes=None, type=String, **kwargs):
         self.parts = parts
         self.quotes = quotes
         self.type = type
+        self.kwargs = kwargs
 
     @classmethod
-    def maybe(cls, parts, quotes=None, type=String):
+    def maybe(cls, parts, quotes=None, type=String, **kwargs):
         """Returns an interpolation if there are multiple parts, otherwise a
         plain Literal.  This keeps the AST somewhat simpler, but also is the
         only way `Literal.from_bareword` gets called.
         """
         if len(parts) > 1:
-            return cls(parts, quotes=quotes, type=type)
+            return cls(parts, quotes=quotes, type=type, **kwargs)
 
         if quotes is None and type is String:
             return Literal.from_bareword(parts[0])
 
-        return Literal(type(parts[0], quotes=quotes))
+        return Literal(type(parts[0], quotes=quotes, **kwargs))
 
     def _render_interpolated(self, value):
         """Return the result of interpolating `value`, which is slightly
@@ -263,7 +264,7 @@ class Interpolation(Expression):
                 value = part.evaluate(calculator, divide)
                 result.append(self._render_interpolated(value))
 
-        return self.type(''.join(result), quotes=self.quotes)
+        return self.type(''.join(result), quotes=self.quotes, **self.kwargs)
 
 
 
diff --git a/scss/grammar/expression.g b/scss/grammar/expression.g
index 9574f28..17eb810 100644
--- a/scss/grammar/expression.g
+++ b/scss/grammar/expression.g
@@ -26,6 +26,7 @@ from scss.ast import MapLiteral
 from scss.ast import ArgspecLiteral
 from scss.cssdefs import unescape
 from scss.types import Color
+from scss.types import Function
 from scss.types import Number
 from scss.types import String
 from scss.types import Url
@@ -78,6 +79,7 @@ parser SassExpression:
     token INTERP_START: "#[{]"
     token INTERP_END: "[}]"
     token INTERP_ANYTHING: "([^#]|#(?![{]))*"
+    token INTERP_NO_PARENS: "([^#()]|#(?![{]))*"
     # http://dev.w3.org/csswg/css-syntax-3/#consume-a-url-token0
     # Bare URLs may not contain quotes, parentheses, or unprintables.  Quoted
     # URLs may, of course, contain whatever they like.
@@ -210,8 +212,11 @@ parser SassExpression:
         # regular function rule, which makes this not quite LL -- but they're
         # different tokens so yapps can't tell, and it resolves the conflict by
         # picking the first one.
+        # TODO Ruby sass somehow allows a full expression in here too
         | "url" LPAR interpolated_url RPAR
-                                    {{ print("url!"); return interpolated_url }}
+            {{ return interpolated_url }}
+        | "expression" LPAR interpolated_function RPAR
+            {{ return Interpolation.maybe(interpolated_function, type=Function, function_name='expression') }}
         | FNCT LPAR argspec RPAR    {{ return CallOp(FNCT, argspec) }}
         | BANG_IMPORTANT            {{ return Literal(String(BANG_IMPORTANT, quotes=None)) }}
         | interpolated_bareword     {{ return Interpolation.maybe(interpolated_bareword) }}
@@ -279,6 +284,23 @@ parser SassExpression:
             BAREWORD                {{ parts.append(BAREWORD) }}
         )*                          {{ return parts }}
 
+    rule interpolated_function:
+        # Completely arbitrary text, but with balanced parentheses.
+        interpolated_function_parens        {{ parts = interpolated_function_parens }}
+        (
+            interpolation                   {{ parts.append(interpolation) }}
+            interpolated_function_parens    {{ parts.extend(interpolated_function_parens) }}
+        )*                                  {{ return parts }}
+
+    rule interpolated_function_parens:
+        INTERP_NO_PARENS            {{ parts = [INTERP_NO_PARENS] }}
+        (
+            LPAR
+            interpolated_function   {{ parts = parts[:-1] + [parts[-1] + LPAR + interpolated_function[0]] + interpolated_function[0:] }}
+            RPAR
+            INTERP_NO_PARENS        {{ parts[-1] += RPAR + INTERP_NO_PARENS }}
+        )*                          {{ return parts }}
+
 
     rule goal_interpolated_anything:
         # This isn't part of the grammar, but rather a separate goal, used for
diff --git a/scss/grammar/expression.py b/scss/grammar/expression.py
index 38f90e3..6caf785 100644
--- a/scss/grammar/expression.py
+++ b/scss/grammar/expression.py
@@ -26,6 +26,7 @@ from scss.ast import MapLiteral
 from scss.ast import ArgspecLiteral
 from scss.cssdefs import unescape
 from scss.types import Color
+from scss.types import Function
 from scss.types import Number
 from scss.types import String
 from scss.types import Url
@@ -39,6 +40,7 @@ from scss.grammar import Scanner
 class SassExpressionScanner(Scanner):
     patterns = None
     _patterns = [
+        ('"expression"', 'expression'),
         ('"url"', 'url'),
         ('":"', ':'),
         ('","', ','),
@@ -80,6 +82,7 @@ class SassExpressionScanner(Scanner):
         ('INTERP_START', '#[{]'),
         ('INTERP_END', '[}]'),
         ('INTERP_ANYTHING', '([^#]|#(?![{]))*'),
+        ('INTERP_NO_PARENS', '([^#()]|#(?![{]))*'),
         ('BAREURL', '(?:[\\\\].|[^#$\'"()\\x00-\\x08\\x0b\\x0e-\\x1f\\x7f]|#(?![{]))*'),
     ]
 
@@ -319,7 +322,13 @@ class SassExpression(Parser):
             LPAR = self._scan('LPAR')
             interpolated_url = self.interpolated_url()
             RPAR = self._scan('RPAR')
-            print("url!"); return interpolated_url
+            return interpolated_url
+        elif _token_ == '"expression"':
+            self._scan('"expression"')
+            LPAR = self._scan('LPAR')
+            interpolated_function = self.interpolated_function()
+            RPAR = self._scan('RPAR')
+            return Interpolation.maybe(interpolated_function, type=Function, function_name='expression')
         elif _token_ == 'FNCT':
             FNCT = self._scan('FNCT')
             LPAR = self._scan('LPAR')
@@ -419,6 +428,28 @@ class SassExpression(Parser):
             parts.append(BAREWORD)
         return parts
 
+    def interpolated_function(self):
+        interpolated_function_parens = self.interpolated_function_parens()
+        parts = interpolated_function_parens
+        while self._peek(self.interpolated_bare_url_rsts) == 'INTERP_START':
+            interpolation = self.interpolation()
+            parts.append(interpolation)
+            interpolated_function_parens = self.interpolated_function_parens()
+            parts.extend(interpolated_function_parens)
+        return parts
+
+    def interpolated_function_parens(self):
+        INTERP_NO_PARENS = self._scan('INTERP_NO_PARENS')
+        parts = [INTERP_NO_PARENS]
+        while self._peek(self.interpolated_function_parens_rsts) == 'LPAR':
+            LPAR = self._scan('LPAR')
+            interpolated_function = self.interpolated_function()
+            parts = parts[:-1] + [parts[-1] + LPAR + interpolated_function[0]] + interpolated_function[0:]
+            RPAR = self._scan('RPAR')
+            INTERP_NO_PARENS = self._scan('INTERP_NO_PARENS')
+            parts[-1] += RPAR + INTERP_NO_PARENS
+        return parts
+
     def goal_interpolated_anything(self):
         INTERP_ANYTHING = self._scan('INTERP_ANYTHING')
         parts = [INTERP_ANYTHING]
@@ -430,40 +461,41 @@ class SassExpression(Parser):
         END = self._scan('END')
         return Interpolation.maybe(parts)
 
-    expr_map_or_list_rsts__ = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'COLOR', 'RPAR', 'BAREWORD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
-    u_expr_chks = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'COLOR', 'BAREWORD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
-    m_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    expr_map_or_list_rsts__ = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'COLOR', '"expression"', 'RPAR', 'BAREWORD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
+    u_expr_chks = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'COLOR', '"expression"', 'BAREWORD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    m_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     argspec_items_rsts = set(['RPAR', 'END', '","'])
     expr_slst_chks = set(['INTERP_END', 'RPAR', 'END', '":"', '","'])
     expr_lst_rsts = set(['INTERP_END', 'END', '","'])
     expr_map_or_list_rsts = set(['RPAR', '":"', '","'])
-    argspec_item_chks = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'COLOR', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    argspec_item_chks = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'COLOR', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     a_expr_chks = set(['ADD', 'SUB'])
-    expr_slst_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'END', 'COLOR', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
-    interpolated_bareword_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
-    or_expr_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'END', 'SINGLE_QUOTE', 'COLOR', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'OR', '","'])
+    interpolated_function_parens_rsts = set(['LPAR', 'RPAR', 'INTERP_START'])
+    expr_slst_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'END', 'COLOR', '"expression"', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
+    interpolated_bareword_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'INTERP_START', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    or_expr_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'END', 'SINGLE_QUOTE', 'COLOR', '"expression"', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'OR', '","'])
     argspec_chks_ = set(['END', 'RPAR'])
     interpolated_string_single_rsts = set(['SINGLE_QUOTE', 'INTERP_START'])
-    and_expr_rsts = set(['AND', 'LPAR', 'RPAR', 'BAREWORD', 'END', 'SINGLE_QUOTE', 'COLOR', 'DOUBLE_QUOTE', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'OR', '","'])
-    comparison_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'ADD', 'FNCT', 'VAR', 'EQ', 'AND', 'GE', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    and_expr_rsts = set(['AND', 'LPAR', 'RPAR', 'BAREWORD', 'END', 'SINGLE_QUOTE', 'COLOR', '"expression"', 'DOUBLE_QUOTE', 'FNCT', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', 'OR', '","'])
+    comparison_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'ADD', 'FNCT', 'VAR', 'EQ', 'AND', 'GE', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     argspec_chks = set(['DOTDOTDOT', 'SLURPYVAR'])
-    atom_rsts_ = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'VAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'UNITS', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    atom_rsts_ = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'VAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'UNITS', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     interpolated_string_double_rsts = set(['DOUBLE_QUOTE', 'INTERP_START'])
     expr_map_or_list_rsts_ = set(['RPAR', '","'])
-    u_expr_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'COLOR', 'SIGN', 'BAREWORD', 'ADD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    u_expr_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'COLOR', '"expression"', 'SIGN', 'BAREWORD', 'ADD', 'NUM', 'FNCT', 'VAR', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     atom_chks = set(['COLOR', 'VAR'])
     interpolated_url_rsts = set(['DOUBLE_QUOTE', 'BAREURL', 'SINGLE_QUOTE'])
     comparison_chks = set(['GT', 'GE', 'NE', 'LT', 'LE', 'EQ'])
-    argspec_items_rsts_ = set(['KWVAR', 'LPAR', 'RPAR', 'BAREWORD', 'END', 'SLURPYVAR', 'COLOR', 'DOTDOTDOT', 'DOUBLE_QUOTE', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
-    a_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    argspec_items_rsts_ = set(['KWVAR', 'LPAR', 'RPAR', 'BAREWORD', 'END', 'SLURPYVAR', 'COLOR', 'DOTDOTDOT', 'DOUBLE_QUOTE', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SINGLE_QUOTE', 'BANG_IMPORTANT', '"expression"'])
+    a_expr_rsts = set(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'COLOR', '"expression"', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', '"url"', 'GT', 'END', 'SIGN', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     interpolated_string_rsts = set(['DOUBLE_QUOTE', 'SINGLE_QUOTE'])
     m_expr_chks = set(['MUL', 'DIV'])
     goal_interpolated_anything_rsts = set(['END', 'INTERP_START'])
     interpolated_bare_url_rsts = set(['RPAR', 'INTERP_START'])
-    argspec_items_chks = set(['KWVAR', '"url"', 'DOUBLE_QUOTE', 'BAREWORD', 'LPAR', 'COLOR', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
-    argspec_rsts = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'SLURPYVAR', 'COLOR', 'BAREWORD', 'DOTDOTDOT', 'RPAR', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SIGN', 'SINGLE_QUOTE'])
-    atom_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'COLOR', 'BAREWORD', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
-    argspec_items_rsts__ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'SLURPYVAR', 'COLOR', 'DOTDOTDOT', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
-    argspec_rsts_ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'COLOR', 'BAREWORD', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
+    argspec_items_chks = set(['KWVAR', '"url"', 'DOUBLE_QUOTE', 'BAREWORD', 'LPAR', 'COLOR', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
+    argspec_rsts = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'SLURPYVAR', 'COLOR', 'BAREWORD', 'DOTDOTDOT', 'RPAR', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SINGLE_QUOTE', 'SIGN', '"expression"'])
+    atom_rsts = set(['"url"', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'COLOR', 'BAREWORD', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])
+    argspec_items_rsts__ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'SLURPYVAR', 'COLOR', 'DOTDOTDOT', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'SINGLE_QUOTE', 'BANG_IMPORTANT', '"expression"'])
+    argspec_rsts_ = set(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'COLOR', 'BAREWORD', '"expression"', 'SIGN', 'VAR', 'ADD', 'NUM', '"url"', 'FNCT', 'NOT', 'RPAR', 'SINGLE_QUOTE'])