merging audreypopp's and lericson's changes -- spritemap support

BUGFIXES

@@ -6,6 +6,10 @@ List of bug fixes since CleverCSS-0.1
 
 9/18/09 - v.0.1.5 - submitted by Tim Babych - LineIterator was not filtering out "\n"s that were left after trimming /* comments */, causing an exception in Parser
 
+9/18/09 - v.0.1.5 - submitted by Tim Babych - The Parser was not aware of negative numbers. Thus any minus sign was an operator, leading to unneeded calculations. Say, "margin: -2px -2px" was converted into "margin: -4px"
+
+9/18/09 - v.0.1.5 - submitted by Tim Babych - LineIterator was not filtering out "\n"s that were left after trimming /* comments */, causing an exception in Parser
+
 9/01/09 - v.0.1.4 - submitted by David Niergarth and 'Lasse' - Missing None check in Engine.evaluate which causes context to always be reset to {}.
 
 4/20/09 - v.0.1.3 - submitted by Antti Kaihola - Using the rgb_to_hls() and hls_to_rgb() functions in CleverCSS to convert colors back and forth reveals a mistake in the HLS to RGB algorithm. Fractional parts are stripped when rounding should be done instead.

bin/ccss

@@ -123,7 +123,7 @@ def convert_many(files, options):
         src = open(fname)
         try:
             try:
-                converted = clevercss.convert(src.read())
+                converted = clevercss.convert(src.read(), fname=fname)
             except (ParserError, EvalException), e:
                 sys.stderr.write('Error in file %s: %s\n' % (fname, e))
                 sys.exit(1)

clevercss/__init__.py

@@ -217,6 +217,25 @@
 
         1, 2, 3, 4, 5
 
+    Spritemaps
+    ----------
+
+    Commonly in CSS, you'll have an image of all your UI elements, and then use
+    background positioning to extract a part of that image. CleverCSS helps you
+    with this, via the `spritemap(fn)` call. For example::
+
+        ui = spritemap('ui.sprites')
+        some_button = $ui.sprite('some_button.png')
+        other_button = $ui.sprite('other_button.png')
+
+        div.some_button:
+            background: $some_button
+
+        div.other_button:
+            background: $other_button
+            width: $other_button.width()
+            height: $other_button.height()
+
     :copyright: Copyright 2007 by Armin Ronacher, Georg Brandl.
     :license: BSD License
 """
@@ -234,11 +253,11 @@ def __init__(self, *args, **kwargs):
             args = ()
         super(Context, self).__init__(*args, **kwargs)
 
-def convert(source, context=None, minified=False):
+def convert(source, context=None, fname=None, minified=False):
     """Convert CleverCSS text into normal CSS."""
     context = Context(context)
     context.minified = minified
-    return engine.Engine(source).to_css(context)
+    return engine.Engine(source, fname=fname).to_css(context)
 
 __all__ = ['convert']