Inject Django's DEBUG setting into sass namespace as $debug

README.rst

@@ -82,10 +82,30 @@ wish to turn this off you do so:
 .. code-block:: python
 
     from django_pyscss import DjangoScssCompiler
-    from django_pyscss.extensions.django import DjangoExtension
+    from django_pyscss.extension import DjangoExtension
 
     compiler = DjangoScssCompiler(extensions=[DjangoExtension])
 
+``DjangoScssCompiler`` can optionally be used with an extension that injects Django's
+``DEBUG`` setting as a variable into the namespace of your SCSS files.:
+
+.. code-block:: python
+
+    from django_pyscss.extension import DjangoExtension, DjangoDebugExtension
+
+    compiler = DjangoScssCompiler(extensions=[DjangoExtension, DjangoDebugExtension])
+
+You can then use the ``$debug`` variable anywhere in your SCSS files.:
+
+.. code-block:: scss
+
+    .debug {
+      visibility: if($debug, visible, hidden);
+    }
+
+Note that you should still omit anything you are not comfortable with people seeing in your
+markup and compiled stylesheets, as that content will still be available in the HTML.
+
 For a list of options that ``DjangoScssCompiler`` accepts, please see the
 pyScss `API documentation <http://pyscss.readthedocs.org/en/latest/python-api.html#new-api>`_.
 

django_pyscss/compiler.py

@@ -12,7 +12,7 @@
 from scss.extension.compass import CompassExtension
 from scss.source import SourceFile
 
-from .extension.django import DjangoExtension
+from .extension import DjangoExtension
 from .utils import find_all_files, get_file_and_storage
 
 

django_pyscss/extension/__init__.py

@@ -0,0 +1,4 @@
+from __future__ import absolute_import
+
+from .django import DjangoExtension
+from .django_debug import DjangoDebugExtension

django_pyscss/extension/django_debug.py

@@ -0,0 +1,16 @@
+from __future__ import absolute_import
+
+from django.conf import settings
+
+from scss.extension import Extension
+from scss.namespace import Namespace
+from scss.types import Boolean
+
+
+class DjangoDebugExtension(Extension):
+    name = 'django_debug'
+
+    def __init__(self):
+        namespace = Namespace()
+        namespace.set_variable('$debug', Boolean(settings.DEBUG))
+        self.namespace = namespace

testproject/testproject/static/css/namespace_debug.scss

@@ -0,0 +1,3 @@
+.debug {
+  visibility: if($debug, visible, hidden);
+}

tests/test_scss.py

@@ -3,11 +3,16 @@
 import mock
 
 from django.test import TestCase
+from django.test.utils import override_settings
 from django.conf import settings
 
 from scss.errors import SassImportError
+from scss.extension.compass import CompassExtension
+from scss.namespace import Namespace
+from scss.types import Boolean
 
 from django_pyscss import DjangoScssCompiler
+from django_pyscss.extension import DjangoExtension, DjangoDebugExtension
 
 from tests.utils import clean_css, CollectStaticTestCase, NoCollectStaticTestCase
 
@@ -43,6 +48,9 @@
 with open(os.path.join(settings.BASE_DIR, 'testproject', 'static', 'css', 'dot.file.scss')) as f:
     DOT_FILE_CONTENTS = f.read()
 
+with open(os.path.join(settings.BASE_DIR, 'testproject', 'static', 'css', 'namespace_debug.scss')) as f:
+    NAMESPACE_DEBUG_CONTENTS = f.read()
+
 
 class CompilerTestMixin(object):
     def setUp(self):
@@ -165,3 +173,39 @@ def test_sprite_images(self):
         # pyScss puts a cachebuster query string on the end of the URLs, lets
         # just check that it made the file that we expected.
         self.assertTrue(re.search(r'url\(/static/scss/assets/images_icons-.+\.png\?_=\d+', actual))
+
+
+NAMESPACE_DEBUG_TRUE_CONTENTS = """
+.debug {
+  visibility: visible;
+}
+"""
+
+NAMESPACE_DEBUG_FALSE_CONTENTS = """
+.debug {
+  visibility: hidden;
+}
+"""
+
+
+@override_settings(DEBUG=True)
+class DebugExtensionTest(TestCase):
+    def test_debug_namespace(self):
+        compiler = DjangoScssCompiler(extensions=(DjangoDebugExtension, DjangoExtension, CompassExtension))
+        actual = compiler.compile_string(NAMESPACE_DEBUG_CONTENTS)
+        self.assertEqual(clean_css(actual), clean_css(NAMESPACE_DEBUG_TRUE_CONTENTS))
+
+    def test_debug_namespace_sass_override(self):
+        compiler = DjangoScssCompiler(extensions=(DjangoDebugExtension, DjangoExtension, CompassExtension))
+        actual = compiler.compile_string('$debug:false;\n' + NAMESPACE_DEBUG_CONTENTS)
+        self.assertEqual(clean_css(actual), clean_css(NAMESPACE_DEBUG_FALSE_CONTENTS))
+
+    def test_debug_namespace_kwarg_override(self):
+        namespace = Namespace()
+        namespace.set_variable('$debug', Boolean(False))
+        compiler = DjangoScssCompiler(
+            extensions=(DjangoDebugExtension, DjangoExtension, CompassExtension),
+            namespace=namespace,
+        )
+        actual = compiler.compile_string(NAMESPACE_DEBUG_CONTENTS)
+        self.assertEqual(clean_css(actual), clean_css(NAMESPACE_DEBUG_FALSE_CONTENTS))