add new pandoc_with_filter function

nbconvert/filters/markdown.py

@@ -118,6 +118,5 @@ def rawlatex2math(text):
         json_data = json.loads(text, object_hook=rawlatex2math_hook)
         return json.dumps(json_data)
 
-    temp_text = 
 
-    return convert_pandoc(source, 'markdown', 'rst', extra_args=extra_args, filter_func=rawlatex2math)
+    return convert_pandoc(source, 'markdown', 'rst', extra_args=extra_args) 

nbconvert/utils/pandoc.py

@@ -56,6 +56,46 @@ def pandoc(source, fmt, to, extra_args=None, encoding='utf-8'):
     out = TextIOWrapper(BytesIO(out), encoding, 'replace').read()
     return out.rstrip('\n')
 
+def pandoc_with_filter(source, fmt, to, filter_func=None,  extra_args=None, encoding='utf-8'):
+    """Convert an input string using pandoc.
+
+    Pandoc converts an input string `from` a format `to` a target format.
+
+    Parameters
+    ----------
+    source : string
+      Input string, assumed to be valid format `from`.
+    fmt : string
+      The name of the input format (markdown, etc.)
+    to : string
+      The name of the output format (html, etc.)
+
+    Returns
+    -------
+    out : unicode
+      Output as returned by pandoc.
+
+    Raises
+    ------
+    PandocMissing
+      If pandoc is not installed.
+    
+    Any error messages generated by pandoc are printed to stderr.
+
+    """
+    cmd = ['pandoc', '-f', fmt, '-t', to]
+    if extra_args:
+        cmd.extend(extra_args)
+
+    # this will raise an exception that will pop us out of here
+    check_pandoc_version()
+
+    # we can safely continue
+    p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    out, _ = p.communicate(cast_bytes(source, encoding))
+    out = TextIOWrapper(BytesIO(out), encoding, 'replace').read()
+    return out.rstrip('\n')
+
 
 def get_pandoc_version():
     """Gets the Pandoc version if Pandoc is installed.