Merge pull request #68 from danc86/unary-negation

Handle unary negation with a separate node type

lesscpy/lessc/parser.py

@@ -25,7 +25,7 @@
 from .scope import Scope
 from .color import Color
 from lesscpy.exceptions import CompilationError
-from lesscpy.plib import Block, Call, Deferred, Expression, Identifier, Mixin, Property, Statement, Variable, Import
+from lesscpy.plib import Block, Call, Deferred, Expression, NegatedExpression, Identifier, Mixin, Property, Statement, Variable, Import
 
 class ErrorRegister(object):
     """
@@ -785,7 +785,7 @@ def p_expression_aux(self, p):
     def p_expression_p_neg(self, p):
         """ expression             : '-' t_popen expression t_pclose
         """
-        p[0] = [p[1], p[3]]
+        p[0] = NegatedExpression([p[3]], 0)
 
     def p_expression_p(self, p):
         """ expression             : t_popen expression t_pclose

lesscpy/plib/__init__.py

@@ -14,6 +14,7 @@
     'Expression',
     'Identifier',
     'Mixin',
+    'NegatedExpression',
     'Node',
     'Property',
     'Statement',
@@ -26,6 +27,7 @@
 from .expression import Expression
 from .identifier import Identifier
 from .mixin import Mixin
+from .negated_expression import NegatedExpression
 from .node import Node
 from .property import Property
 from .statement import Statement

lesscpy/plib/expression.py

@@ -9,7 +9,6 @@
 """
 
 import operator
-import six
 
 from .node import Node
 from lesscpy.lessc import utility
@@ -19,7 +18,8 @@
 class Expression(Node):
 
     """Expression node. Parses all expression except
-    color expressions, (handled in the color class)
+    color expressions (handled in the color class)
+    and unary negation (handled in the NegatedExpression class).
     """
 
     def parse(self, scope):
@@ -33,7 +33,6 @@ def parse(self, scope):
         """
         assert(len(self.tokens) == 3)
         expr = self.process(self.tokens, scope)
-        expr = [self.neg(t, scope) for t in expr]
         A, O, B = [e[0]
                    if isinstance(e, tuple)
                    else e
@@ -56,25 +55,6 @@ def parse(self, scope):
             return out
         return self.with_units(out, ua, ub)
 
-    def neg(self, value, scope):
-        """Apply negativity.
-        args:
-            value (mixed): test value
-            scope (Scope): Current scope
-        raises:
-            SyntaxError
-        returns:
-            str
-        """
-        if value and isinstance(value, list) and value[0] == '-':
-            val = value[1]
-            if len(value) > 1 and hasattr(value[1], 'parse'):
-                val = value[1].parse(scope)
-            if isinstance(val, six.string_types):
-                return '-' + val
-            return -val
-        return value
-
     def with_units(self, val, ua, ub):
         """Return value with unit.
         args:

lesscpy/plib/negated_expression.py

@@ -0,0 +1,23 @@
+# -*- coding: utf8 -*-
+"""
+.. module:: lesscpy.plib.negated_expression
+    :synopsis: Node for unary negated expressions.
+
+    Copyright (c)
+    See LICENSE for details.
+"""
+
+import six
+
+from .node import Node
+
+
+class NegatedExpression(Node):
+
+    """Expressions preceded by unary negation."""
+
+    def parse(self, scope):
+        val, = self.process(self.tokens, scope)
+        if isinstance(val, six.string_types):
+            return '-' + val
+        return -val

test/css/issues/issue67.css

@@ -0,0 +1,3 @@
+.c {
+	left: 4;
+}

test/less/issues/issue67.less

@@ -0,0 +1 @@
+.c { left: -(1 + 1) * -(1 + 1); }