Gradients _position() optimizations and default positions

2 files changed, 17 insertions, 15 deletions

diff --git a/scss/functions/compass/gradients.py b/scss/functions/compass/gradients.py
index 5119b39..20646f1 100644
--- a/scss/functions/compass/gradients.py
+++ b/scss/functions/compass/gradients.py
@@ -314,8 +314,8 @@ def linear_gradient(*args):
     def to__owg():
         args = [
             'linear',
-            position(position_and_angle or ['center', 'top']),
-            opposite_position(position_and_angle or ['center', 'top']),
+            position(position_and_angle or None),
+            opposite_position(position_and_angle or None),
         ]
         args.extend('color-stop(%s, %s)' % (to_str(s), c) for s, c in color_stops)
         ret = '-webkit-gradient(' + ', '.join(to_str(a) for a in args or [] if a is not None) + ')'
diff --git a/scss/functions/compass/helpers.py b/scss/functions/compass/helpers.py
index bde12ef..3300df9 100644
--- a/scss/functions/compass/helpers.py
+++ b/scss/functions/compass/helpers.py
@@ -364,29 +364,31 @@ def range_(frm, through=None):
 # ------------------------------------------------------------------------------
 # Working with CSS constants
 
-OPPOSITE_POSITIONS = dict(
-    top='bottom',
-    bottom='top',
-    left='right',
-    right='left',
-    center='center',
-)
+OPPOSITE_POSITIONS = {
+    'top': StringValue('bottom', quotes=None),
+    'bottom': StringValue('top', quotes=None),
+    'left': StringValue('right', quotes=None),
+    'right': StringValue('left', quotes=None),
+    'center': StringValue('center', quotes=None),
+}
+DEFAULT_POSITION = [StringValue('center', quotes=None), StringValue('top', quotes=None)]
 
 
 def _position(opposite, positions):
-    positions = List.from_maybe(positions)
+    if positions is None:
+        positions = DEFAULT_POSITION
+    else:
+        positions = List.from_maybe(positions)
 
     ret = []
     for pos in positions:
         if isinstance(pos, (StringValue, six.string_types)):
-            _pos = getattr(pos, 'value', pos)
-            if _pos in OPPOSITE_POSITIONS:
+            pos_value = getattr(pos, 'value', pos)
+            if pos_value in OPPOSITE_POSITIONS:
                 if opposite:
-                    opp = OPPOSITE_POSITIONS[pos]
-                    ret.append(StringValue(opp, quotes=None))
+                    ret.append(OPPOSITE_POSITIONS[pos_value])
                 else:
                     ret.append(pos)
-
                 continue
 
         elif isinstance(pos, NumberValue):