Merge pull request #314 from xen0n/modulo-expression

Support for modulo expressions

4 files changed, 37 insertions, 7 deletions

diff --git a/scss/grammar/expression.g b/scss/grammar/expression.g
index 454e112..8f4e5ad 100644
--- a/scss/grammar/expression.g
+++ b/scss/grammar/expression.g
@@ -61,6 +61,7 @@ parser SassExpression:
     token END: "$"
     token MUL: "[*]"
     token DIV: "/"
+    token MOD: "(?<=\s)%"
     token ADD: "[+]"
     token SUB: "-\s"
     token SIGN: "-(?![a-zA-Z_])"
@@ -218,6 +219,7 @@ parser SassExpression:
         (
             MUL u_expr              {{ v = BinaryOp(operator.mul, v, u_expr) }}
             | DIV u_expr            {{ v = BinaryOp(operator.truediv, v, u_expr) }}
+            | MOD u_expr            {{ v = BinaryOp(operator.mod, v, u_expr) }}
         )*                          {{ return v }}
 
     rule u_expr:
diff --git a/scss/grammar/expression.py b/scss/grammar/expression.py
index b2ba877..a808eae 100644
--- a/scss/grammar/expression.py
+++ b/scss/grammar/expression.py
@@ -58,6 +58,7 @@ class SassExpressionScanner(Scanner):
         ('END', '$'),
         ('MUL', '[*]'),
         ('DIV', '/'),
+        ('MOD', '(?<=\\s)%'),
         ('ADD', '[+]'),
         ('SUB', '-\\s'),
         ('SIGN', '-(?![a-zA-Z_])'),
@@ -291,10 +292,14 @@ class SassExpression(Parser):
                 MUL = self._scan('MUL')
                 u_expr = self.u_expr()
                 v = BinaryOp(operator.mul, v, u_expr)
-            else:  # == 'DIV'
+            elif _token_ == 'DIV':
                 DIV = self._scan('DIV')
                 u_expr = self.u_expr()
                 v = BinaryOp(operator.truediv, v, u_expr)
+            else:  # == 'MOD'
+                MOD = self._scan('MOD')
+                u_expr = self.u_expr()
+                v = BinaryOp(operator.mod, v, u_expr)
         return v
 
     def u_expr(self):
@@ -517,7 +522,7 @@ class SassExpression(Parser):
     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'])
-    m_expr_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', 'OR', '","'])
+    m_expr_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', '","'])
     interpolated_bare_url_rsts_ = frozenset(['RPAR', 'INTERP_START', 'BAREURL', 'SPACE'])
     argspec_items_rsts = frozenset(['RPAR', 'END', '","'])
     expr_slst_chks = frozenset(['INTERP_END', 'RPAR', 'END', '":"', '","'])
@@ -527,12 +532,12 @@ class SassExpression(Parser):
     a_expr_chks = frozenset(['ADD', 'SUB'])
     interpolated_function_parens_rsts = frozenset(['LPAR', 'RPAR', 'INTERP_START'])
     expr_slst_rsts = frozenset(['LPAR', 'DOUBLE_QUOTE', 'VAR', 'END', 'URL_FUNCTION', 'BAREWORD', 'COLOR', 'ALPHA_FUNCTION', 'INTERP_START', 'FNCT', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'RPAR', '":"', 'NOT', 'INTERP_END', 'BANG_IMPORTANT', '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', 'SPACE', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
-    atom_rsts__ = frozenset(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'ALPHA_FUNCTION', 'RPAR', 'VAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'UNITS', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    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', 'SPACE', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'MOD', 'OR', '","'])
+    atom_rsts__ = frozenset(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'ALPHA_FUNCTION', 'RPAR', 'VAR', 'MUL', 'INTERP_END', 'BANG_IMPORTANT', 'DIV', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'UNITS', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'MOD', 'OR', '","'])
     or_expr_rsts = frozenset(['LPAR', 'DOUBLE_QUOTE', 'ALPHA_FUNCTION', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NUM', '":"', 'BAREWORD', 'END', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'FNCT', 'VAR', 'OR', 'NOT', 'SINGLE_QUOTE', '","'])
     argspec_chks_ = frozenset(['END', 'RPAR'])
     interpolated_string_single_rsts = frozenset(['SINGLE_QUOTE', 'INTERP_START'])
-    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', '":"', 'BAREWORD', 'GT', 'END', 'SPACE', 'SIGN', 'LITERAL_FUNCTION', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
+    interpolated_bareword_rsts_ = frozenset(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'ALPHA_FUNCTION', 'RPAR', 'MUL', 'DIV', 'BANG_IMPORTANT', 'INTERP_END', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'BAREWORD', 'GT', 'END', 'SPACE', 'SIGN', 'LITERAL_FUNCTION', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'MOD', 'OR', '","'])
     and_expr_rsts = frozenset(['LPAR', 'DOUBLE_QUOTE', 'ALPHA_FUNCTION', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NUM', '":"', 'BAREWORD', 'END', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'FNCT', 'VAR', 'AND', 'OR', 'NOT', 'SINGLE_QUOTE', '","'])
     comparison_rsts = frozenset(['LPAR', 'DOUBLE_QUOTE', 'ALPHA_FUNCTION', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'ADD', 'FNCT', 'VAR', 'EQ', 'AND', 'GE', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     argspec_chks = frozenset(['DOTDOTDOT', 'SLURPYVAR'])
@@ -548,8 +553,8 @@ class SassExpression(Parser):
     argspec_items_rsts_ = frozenset(['KWVAR', 'LPAR', 'DOUBLE_QUOTE', 'VAR', 'END', 'SLURPYVAR', 'URL_FUNCTION', 'BAREWORD', 'COLOR', 'ALPHA_FUNCTION', 'DOTDOTDOT', 'INTERP_START', 'SIGN', 'LITERAL_FUNCTION', 'ADD', 'NUM', 'RPAR', 'FNCT', 'NOT', 'BANG_IMPORTANT', 'SINGLE_QUOTE'])
     a_expr_rsts = frozenset(['LPAR', 'DOUBLE_QUOTE', 'SUB', 'ALPHA_FUNCTION', 'RPAR', 'INTERP_END', 'BANG_IMPORTANT', 'LE', 'URL_FUNCTION', 'INTERP_START', 'COLOR', 'NE', 'LT', 'NUM', '":"', 'LITERAL_FUNCTION', 'GT', 'END', 'SIGN', 'BAREWORD', 'GE', 'FNCT', 'VAR', 'EQ', 'AND', 'ADD', 'SINGLE_QUOTE', 'NOT', 'OR', '","'])
     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', 'OR', '","'])
-    m_expr_chks = frozenset(['MUL', 'DIV'])
+    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'])
     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'])
diff --git a/scss/tests/test_expression.py b/scss/tests/test_expression.py
index d895948..33adfe2 100644
--- a/scss/tests/test_expression.py
+++ b/scss/tests/test_expression.py
@@ -55,6 +55,11 @@ def test_reference_operations():
     assert calc('#{$font-size}/#{$line-height}') == String('12px / 30px')
                                             # uses #{}; does no division
 
+    # Modulo
+    assert calc('29 % 12') == Number(5)
+    assert calc('29px % 12') == Number(5, 'px')
+    assert calc('29px % 12px') == Number(5, 'px')
+
     # Color operations
     ns.set_variable('$translucent-red', Color.from_rgb(1, 0, 0, 0.5))
     ns.set_variable('$green', Color.from_name('lime'))
diff --git a/scss/types.py b/scss/types.py
index 092f93b..54345da 100644
--- a/scss/types.py
+++ b/scss/types.py
@@ -396,6 +396,24 @@ class Number(Value):
 
         return Number(amount, unit_numer=numer, unit_denom=denom)
 
+    def __mod__(self, other):
+        if not isinstance(other, Number):
+            return NotImplemented
+
+        amount = self.value % other.value
+
+        if self.is_unitless:
+            return Number(amount)
+
+        if not other.is_unitless:
+            left = self.to_base_units()
+            right = other.to_base_units()
+
+            if left.unit_numer != right.unit_numer or left.unit_denom != right.unit_denom:
+                raise ValueError("Can't reconcile units: %r and %r" % (self, other))
+
+        return Number(amount, unit_numer=self.unit_numer, unit_denom=self.unit_denom)
+
     def __add__(self, other):
         # Numbers auto-cast to strings when added to other strings
         if isinstance(other, String):