support IPython 2.0 in notebook liquid tag

The only relevant changes seem to be a few renamed classes, and changed signatures.

liquid_tags/notebook.py

@@ -55,7 +55,12 @@ if not LooseVersion(IPython.__version__) >= '1.0':
 
 from IPython import nbconvert
 
-from IPython.nbconvert.filters.highlight import _pygment_highlight
+try:
+    from IPython.nbconvert.filters.highlight import _pygments_highlight
+except ImportError:
+    # IPython < 2.0
+    from IPython.nbconvert.filters.highlight import _pygment_highlight as _pygments_highlight
+
 from pygments.formatters import HtmlFormatter
 
 from IPython.nbconvert.exporters import HTMLExporter
@@ -64,9 +69,10 @@ from IPython.config import Config
 from IPython.nbformat import current as nbformat
 
 try:
-    from IPython.nbconvert.transformers import Transformer
+    from IPython.nbconvert.preprocessors import Preprocessor
 except ImportError:
-    raise ValueError("IPython version 2.0 is not yet supported")
+    # IPython < 2.0
+    from IPython.nbconvert.transformers import Transformer as Preprocessor
 
 from IPython.utils.traitlets import Integer
 from copy import deepcopy
@@ -144,7 +150,7 @@ CSS_WRAPPER = """
 
 
 #----------------------------------------------------------------------
-# Create a custom transformer
+# Create a custom preprocessor
 class SliceIndex(Integer):
     """An integer trait that accepts None"""
     default_value = None
@@ -156,20 +162,22 @@ class SliceIndex(Integer):
             return super(SliceIndex, self).validate(obj, value)
 
 
-class SubCell(Transformer):
+class SubCell(Preprocessor):
     """A transformer to select a slice of the cells of a notebook"""
     start = SliceIndex(0, config=True,
                        help="first cell of notebook to be converted")
     end = SliceIndex(None, config=True,
                      help="last cell of notebook to be converted")
 
-    def call(self, nb, resources):
+    def preprocess(self, nb, resources):
         nbc = deepcopy(nb)
-        for worksheet in nbc.worksheets :
+        for worksheet in nbc.worksheets:
             cells = worksheet.cells[:]
             worksheet.cells = cells[self.start:self.end]
         return nbc, resources
 
+    call = preprocess # IPython < 2.0
+
 
 #----------------------------------------------------------------------
 # Customize the html template:
@@ -205,9 +213,11 @@ pelican_loader = DictLoader({'pelicanhtml.tpl':
 #----------------------------------------------------------------------
 # Custom highlighter:
 #  instead of using class='highlight', use class='highlight-ipynb'
-def custom_highlighter(source, language='ipython'):
+def custom_highlighter(source, language='ipython', metadata=None):
     formatter = HtmlFormatter(cssclass='highlight-ipynb')
-    output = _pygment_highlight(source, formatter, language)
+    if not language:
+        language = 'ipython'
+    output = _pygments_highlight(source, formatter, language)
     return output.replace('<pre>', '<pre class="ipynb">')
 
 
@@ -252,12 +262,17 @@ def notebook(preprocessor, tag, markup):
                     {'enabled':True, 'highlight_class':'.highlight-ipynb'},
                 'SubCell':
                     {'enabled':True, 'start':start, 'end':end}})
-
+    
+    if LooseVersion(IPython.__version__) >= '2.0':
+        subcell_kwarg = dict(preprocessors=[SubCell])
+    else:
+        subcell_kwarg = dict(transformers=[SubCell])
+    
     exporter = HTMLExporter(config=c,
                             template_file='basic',
                             filters={'highlight2html': custom_highlighter},
-                            transformers=[SubCell],
-                            extra_loaders=[pelican_loader])
+                            extra_loaders=[pelican_loader],
+                            **subcell_kwarg)
 
     # read and parse the notebook
     with open(nb_path) as f: