1 files changed, 31 insertions, 2 deletions
diff --git a/nikola/plugins/compile_markdown/__init__.py b/nikola/plugins/compile_markdown/__init__.py
index 958cfa3..1a58a98 100644
--- a/nikola/plugins/compile_markdown/__init__.py
+++ b/nikola/plugins/compile_markdown/__init__.py
@@ -1,20 +1,49 @@
+# Copyright (c) 2012 Roberto Alsina y otros.
+
+# Permission is hereby granted, free of charge, to any
+# person obtaining a copy of this software and associated
+# documentation files (the "Software"), to deal in the
+# Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the
+# Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice
+# shall be included in all copies or substantial portions of
+# the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
 """Implementation of compile_html based on markdown."""
 
 import codecs
 import os
 import re
 
-from markdown import markdown
+try:
+    from markdown import markdown
+except ImportError:
+    markdown = None
 
 from nikola.plugin_categories import PageCompiler
 
 
 class CompileMarkdown(PageCompiler):
-    """Compile reSt into HTML."""
+    """Compile markdown into HTML."""
 
     name = "markdown"
 
     def compile_html(self, source, dest):
+        if markdown is None:
+            raise Exception('To build this site, you need to install the "markdown" package.')
         try:
             os.makedirs(os.path.dirname(dest))
         except: