make default language highlight configurable for html

IPython/nbconvert/exporters/templateexporter.py

@@ -43,7 +43,7 b' default_filters = {'
         'ansi2html': filters.ansi2html,
         'filter_data_type': filters.DataTypeFilter,
         'get_lines': filters.get_lines,
-        'highlight2html': filters.highlight2html,
+        'highlight2html': filters.Highlight2Html,
         'highlight2latex': filters.highlight2latex,
         'ipython2python': filters.ipython2python,
         'posix_path': filters.posix_path,

IPython/nbconvert/filters/highlight.py

@@ -18,6 +18,8 b' from pygments import highlight as pygements_highlight'
 from pygments.lexers import get_lexer_by_name
 from pygments.formatters import HtmlFormatter
 from pygments.formatters import LatexFormatter
+from IPython.config import catch_config_error, Configurable
+from IPython.utils.traitlets import Unicode
 
 # Our own imports
 from IPython.nbconvert.utils.lexers import IPythonLexer
@@ -33,12 +35,16 b" MULTILINE_OUTPUTS = ['text', 'html', 'svg', 'latex', 'javascript', 'json']"
 #-----------------------------------------------------------------------------
 
 __all__ = [
-    'highlight2html',
+    'Highlight2Html',
     'highlight2latex'
 ]
 
 
-def highlight2html(source, language='ipython', metadata=None):
+class Highlight2Html(Configurable):
+
+    language = Unicode('ipython', config=True, help='default highlight language')
+
+    def __call__(self, source, language=None, metadata=None):
     """
     Return a syntax-highlighted version of the input source as html output.
 
@@ -51,6 +57,8 b" def highlight2html(source, language='ipython', metadata=None):"
     metadata : NotebookNode cell metadata
         metadata of the cell to highlight
     """
+        if not language:
+            language=self.language
 
     return _pygment_highlight(source, HtmlFormatter(), language, metadata)