Stop using apply_vars on block arguments; use the parser instead.

4 files changed, 58 insertions, 9 deletions

diff --git a/scss/calculator.py b/scss/calculator.py
index 39eb623..c6c8fb1 100644
--- a/scss/calculator.py
+++ b/scss/calculator.py
@@ -113,12 +113,12 @@ class Calculator(object):
         return cont
 
     def calculate(self, expression, divide=False):
-        expression = self.evaluate_expression(expression, divide=divide)
+        result = self.evaluate_expression(expression, divide=divide)
 
-        if expression is None:
+        if result is None:
             return String.unquoted(self.apply_vars(expression))
 
-        return expression
+        return result
 
     # TODO only used by magic-import...?
     def interpolate(self, var):
@@ -179,6 +179,18 @@ class Calculator(object):
         # must not have any interpolations, right?
         if '#' not in string:
             return Literal(String.unquoted(string))
-        return self.parse_expression(string, 'goal_interpolated_anything')
+        return self.parse_expression(string, 'goal_interpolated_literal')
+
+    def parse_vars_and_interpolations(self, string):
+        """Parse a string for variables and interpolations, but don't treat
+        anything else as Sass syntax.  Returns an AST node.
+        """
+        # Shortcut: if there are no #s or $s in the string in the first place,
+        # it must not have anything of interest.
+        if '#' not in string and '$' not in string:
+            return Literal(String.unquoted(string))
+        return self.parse_expression(
+            string, 'goal_interpolated_literal_with_vars')
+
 
 __all__ = ('Calculator',)
diff --git a/scss/compiler.py b/scss/compiler.py
index 9bc912d..434f7ac 100644
--- a/scss/compiler.py
+++ b/scss/compiler.py
@@ -1139,7 +1139,11 @@ class Compilation(object):
         # generally?
         calculator = self._make_calculator(rule.namespace)
         if block.header.argument:
-            block.header.argument = calculator.apply_vars(block.header.argument)
+            # TODO is this correct?  do ALL at-rules ALWAYS allow both vars and
+            # interpolation?
+            node = calculator.parse_vars_and_interpolations(
+                block.header.argument)
+            block.header.argument = node.evaluate(calculator).render()
 
         # TODO merge into RuleAncestry
         new_ancestry = list(rule.ancestry.headers)
diff --git a/scss/grammar/expression.g b/scss/grammar/expression.g
index 8f4e5ad..fef8959 100644
--- a/scss/grammar/expression.g
+++ b/scss/grammar/expression.g
@@ -45,6 +45,7 @@ parser SassExpression:
     token SINGLE_STRING_GUTS: '([^\'\\\\#]|[\\\\].|#(?![{]))*'
     token DOUBLE_STRING_GUTS: "([^\"\\\\#]|[\\\\].|#(?![{]))*"
     token INTERP_ANYTHING: "([^#]|#(?![{]))*"
+    token INTERP_NO_VARS: "([^#$]|#(?![{]))*"
     token INTERP_NO_PARENS: "([^#()]|#(?![{]))*"
 
     # This is a stupid lookahead used for diverting url(#{...}) to its own
@@ -374,7 +375,7 @@ parser SassExpression:
         )*                          {{ return parts }}
 
 
-    rule goal_interpolated_anything:
+    rule goal_interpolated_literal:
         # This isn't part of the grammar, but rather a separate goal, used for
         # text that might contain interpolations but should not be parsed
         # outside of them -- e.g., selector strings.
@@ -385,4 +386,17 @@ parser SassExpression:
         )*
         END                         {{ return Interpolation.maybe(parts) }}
 
+    rule goal_interpolated_literal_with_vars:
+        # Another goal used for literal text that might contain interpolations
+        # OR variables.  Created for the header of @media blocks.
+        INTERP_NO_VARS              {{ parts = [INTERP_NO_VARS] }}
+        (
+            (
+                interpolation       {{ parts.append(interpolation) }}
+                | VAR               {{ parts.append(Variable(VAR)) }}
+            )
+            INTERP_NO_VARS          {{ parts.append(INTERP_NO_VARS) }}
+        )*
+        END                         {{ return Interpolation.maybe(parts) }}
+
 %%
diff --git a/scss/grammar/expression.py b/scss/grammar/expression.py
index a808eae..1d2a6b5 100644
--- a/scss/grammar/expression.py
+++ b/scss/grammar/expression.py
@@ -48,6 +48,7 @@ class SassExpressionScanner(Scanner):
         ('SINGLE_STRING_GUTS', "([^'\\\\#]|[\\\\].|#(?![{]))*"),
         ('DOUBLE_STRING_GUTS', '([^"\\\\#]|[\\\\].|#(?![{]))*'),
         ('INTERP_ANYTHING', '([^#]|#(?![{]))*'),
+        ('INTERP_NO_VARS', '([^#$]|#(?![{]))*'),
         ('INTERP_NO_PARENS', '([^#()]|#(?![{]))*'),
         ('INTERP_START_URL_HACK', '(?=[#][{])'),
         ('INTERP_START', '#[{]'),
@@ -508,10 +509,10 @@ class SassExpression(Parser):
             parts[-1] += RPAR + INTERP_NO_PARENS
         return parts
 
-    def goal_interpolated_anything(self):
+    def goal_interpolated_literal(self):
         INTERP_ANYTHING = self._scan('INTERP_ANYTHING')
         parts = [INTERP_ANYTHING]
-        while self._peek(self.goal_interpolated_anything_rsts) == 'INTERP_START':
+        while self._peek(self.goal_interpolated_literal_rsts) == 'INTERP_START':
             interpolation = self.interpolation()
             parts.append(interpolation)
             INTERP_ANYTHING = self._scan('INTERP_ANYTHING')
@@ -519,6 +520,22 @@ class SassExpression(Parser):
         END = self._scan('END')
         return Interpolation.maybe(parts)
 
+    def goal_interpolated_literal_with_vars(self):
+        INTERP_NO_VARS = self._scan('INTERP_NO_VARS')
+        parts = [INTERP_NO_VARS]
+        while self._peek(self.goal_interpolated_literal_with_vars_rsts) != 'END':
+            _token_ = self._peek(self.goal_interpolated_literal_with_vars_rsts_)
+            if _token_ == 'INTERP_START':
+                interpolation = self.interpolation()
+                parts.append(interpolation)
+            else:  # == 'VAR'
+                VAR = self._scan('VAR')
+                parts.append(Variable(VAR))
+            INTERP_NO_VARS = self._scan('INTERP_NO_VARS')
+            parts.append(INTERP_NO_VARS)
+        END = self._scan('END')
+        return Interpolation.maybe(parts)
+
     atom_chks_ = frozenset(['BAREWORD', 'INTERP_START'])
     expr_map_or_list_rsts__ = frozenset(['LPAR', 'DOUBLE_QUOTE', 'VAR', 'URL_FUNCTION', 'BAREWORD', 'COLOR', 'ALPHA_FUNCTION', 'INTERP_START', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'RPAR', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE', '","'])
     u_expr_chks = frozenset(['LPAR', 'DOUBLE_QUOTE', 'BAREWORD', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'ALPHA_FUNCTION', 'VAR', 'NUM', 'FNCT', 'LITERAL_FUNCTION', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
@@ -527,7 +544,9 @@ class SassExpression(Parser):
     argspec_items_rsts = frozenset(['RPAR', 'END', '","'])
     expr_slst_chks = frozenset(['INTERP_END', 'RPAR', 'END', '":"', '","'])
     expr_lst_rsts = frozenset(['INTERP_END', 'RPAR', 'END', '","'])
+    goal_interpolated_literal_rsts = frozenset(['END', 'INTERP_START'])
     expr_map_or_list_rsts = frozenset(['RPAR', '":"', '","'])
+    goal_interpolated_literal_with_vars_rsts = frozenset(['VAR', 'END', 'INTERP_START'])
     argspec_item_chks = frozenset(['LPAR', 'DOUBLE_QUOTE', 'VAR', 'URL_FUNCTION', 'BAREWORD', 'COLOR', 'ALPHA_FUNCTION', 'INTERP_START', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     a_expr_chks = frozenset(['ADD', 'SUB'])
     interpolated_function_parens_rsts = frozenset(['LPAR', 'RPAR', 'INTERP_START'])
@@ -555,7 +574,7 @@ class SassExpression(Parser):
     interpolated_string_rsts = frozenset(['DOUBLE_QUOTE', 'SINGLE_QUOTE'])
     interpolated_bareword_rsts__ = frozenset(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'ALPHA_FUNCTION', 'RPAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'MOD', 'OR', '","'])
     m_expr_chks = frozenset(['MUL', 'DIV', 'MOD'])
-    goal_interpolated_anything_rsts = frozenset(['END', 'INTERP_START'])
+    goal_interpolated_literal_with_vars_rsts_ = frozenset(['VAR', 'INTERP_START'])
     interpolated_bare_url_rsts = frozenset(['RPAR', 'INTERP_START'])
     argspec_items_chks = frozenset(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'VAR', 'URL_FUNCTION', 'BAREWORD', 'COLOR', 'ALPHA_FUNCTION', 'INTERP_START', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     argspec_rsts = frozenset(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'BANG_IMPORTANT', 'END', 'SLURPYVAR', 'URL_FUNCTION', 'BAREWORD', 'COLOR', 'ALPHA_FUNCTION', 'DOTDOTDOT', 'INTERP_START', 'RPAR', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'VAR', 'FNCT', 'NOT', 'SIGN', 'SINGLE_QUOTE'])