add markdown2html filter

uses pandoc instead of Python markdown for better consistency.

Also eliminates one dependency.

IPython/nbconvert/exporters/exporter.py

@@ -24,7 +24,6 b' from copy import deepcopy'
 
 # other libs/dependencies
 from jinja2 import Environment, FileSystemLoader
-from markdown import markdown
 
 # IPython imports
 from IPython.config.configurable import Configurable
@@ -45,7 +44,7 b" JINJA_EXTENSIONS = ['jinja2.ext.loopcontrols']"
 
 default_filters = {
         'indent': indent,
-        'markdown': markdown,
+        'markdown': filters.markdown2html,
         'ansi2html': filters.ansi2html,
         'filter_data_type': filters.DataTypeFilter,
         'get_lines': filters.get_lines,

IPython/nbconvert/filters/markdown.py

@@ -19,16 +19,18 b' from __future__ import print_function'
 import sys
 import subprocess
 
+from IPython.nbconvert.utils.pandoc import pandoc
+
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 __all__ = [
+    'markdown2html',
     'markdown2latex',
     'markdown2rst'
 ]
 
-
 def markdown2latex(source):
     """Convert a markdown string to LaTeX via pandoc.
 
@@ -45,18 +47,13 b' def markdown2latex(source):'
     out : string
       Output as returned by pandoc.
     """
-    p = subprocess.Popen('pandoc -f markdown -t latex'.split(),
-                         stdin=subprocess.PIPE, stdout=subprocess.PIPE)
-    
-    out, err = p.communicate(source.encode('utf-8'))
-    
-    if err:
-        print(err, file=sys.stderr)
-    #print('*'*20+'\n', out, '\n'+'*'*20)  # dbg
-    
-    return unicode(out, 'utf-8')[:-1]
+    return pandoc(source, 'markdown', 'latex')
 
 
+def markdown2html(source):
+    """Convert a markdown string to HTML via pandoc"""
+    return pandoc(source, 'markdown', 'html')
+
 def markdown2rst(source):
     """Convert a markdown string to LaTeX via pandoc.
 
@@ -73,13 +70,5 b' def markdown2rst(source):'
     out : string
       Output as returned by pandoc.
     """
-    p = subprocess.Popen('pandoc -f markdown -t rst'.split(),
-                         stdin=subprocess.PIPE, stdout=subprocess.PIPE)
-    
-    out, err = p.communicate(source.encode('utf-8'))
-    
-    if err:
-        print(err, file=sys.stderr)
-    #print('*'*20+'\n', out, '\n'+'*'*20)  # dbg
-    
-    return unicode(out, 'utf-8')
+    return pandoc(source, 'markdown', 'rst')
+