Add support for Markdown

src/rstpreview/markup.py

@@ -3,6 +3,12 @@ try:
     import docutils.core
 except ImportError:
     docutils = None
+try:
+    import markdown
+except ImportError:
+    markdown = None
+else:
+    import markdown.extensions.codehilite
 
 
 def get_previewer(source):
@@ -60,6 +66,39 @@ class ReStructuredTextPreviewer(BasePreviewer):
         )['html_body']
 
 
+class MarkdownPreviewer(BasePreviewer):
+
+    def __init__(self, source):
+        super(MarkdownPreviewer, self).__init__(source)
+        self.extensions = [
+            markdown.extensions.codehilite.CodeHiliteExtension(
+                css_class='code',
+            ),
+        ]
+
+    @classmethod
+    def detect(cls, lines):
+        if markdown is None:
+            return False
+        for idx, line in enumerate(lines):
+            if line.lstrip().startswith('#'):  # heading
+                return True
+            if '![' in line:  # image
+                return True
+            if '](' in line:  # inline link
+                return True
+            if line.startswith('[') and ']:' in line:  # reference-style link
+                return True
+            if line.startswith('    '):  # code block
+                # reStructuredText has a similar syntax, so make sure
+                # it isn't that
+                if idx and not line[idx - 1].endswith('::'):
+                    return True
+
+    def preview(self):
+        return markdown.markdown(self.source, extensions=self.extensions)
+
+
 class PlainTextPreviewer(BasePreviewer):
 
     def preview(self):