add posix_path filter

mainly for unixy things on Windows (latex) that don't allow Windows paths.

IPython/nbconvert/exporters/exporter.py

@@ -55,6 +55,7 b' default_filters = {'
         'highlight2html': filters.highlight2html,
         'highlight2latex': filters.highlight2latex,
         'ipython2python': filters.ipython2python,
+        'posix_path': filters.posix_path,
         'markdown2latex': filters.markdown2latex,
         'markdown2rst': filters.markdown2rst,
         'comment_lines': filters.comment_lines,
@@ -66,7 +67,7 b' default_filters = {'
         'ansi2latex': filters.ansi2latex,
         'strip_math_space': filters.strip_math_space,
         'wrap_text': filters.wrap_text,
-        'escape_latex': filters.escape_latex
+        'escape_latex': filters.escape_latex,
 }
 
 #-----------------------------------------------------------------------------

IPython/nbconvert/filters/strings.py

@@ -16,6 +16,7 b' templates.'
 # Imports
 #-----------------------------------------------------------------------------
 
+import os
 import re
 import textwrap
 from xml.etree import ElementTree
@@ -36,6 +37,7 b' __all__ = ['
     'comment_lines',
     'get_lines',
     'ipython2python',
+    'posix_path',
 ]
 
 
@@ -169,3 +171,13 b' def ipython2python(code):'
     """
     shell = InteractiveShell.instance()
     return shell.input_transformer_manager.transform_cell(code)
+
+def posix_path(path):
+    """Turn a path into posix-style path/to/etc
+    
+    Mainly for use in latex on Windows,
+    where native Windows paths are not allowed.
+    """
+    if os.path.sep != '/':
+        return path.replace(os.path.sep, '/')
+    return path

IPython/nbconvert/filters/tests/test_strings.py

@@ -17,7 +17,8 b' Module with tests for Strings'
 from IPython.testing import decorators as dec
 from ...tests.base import TestsBase
 from ..strings import (wrap_text, html2text, add_anchor, strip_dollars, 
-    strip_files_prefix, get_lines, comment_lines, ipython2python)
+    strip_files_prefix, get_lines, comment_lines, ipython2python, posix_path,
+)
 
 
 #-----------------------------------------------------------------------------
@@ -117,3 +118,10 b' class TestStrings(TestsBase):'
         results = ipython2python(u'%%pylab\nprint("Hello-World")').replace("u'", "'")
         self.fuzzy_compare(results, u"get_ipython().run_cell_magic('pylab', '', 'print(\"Hello-World\")')", 
             ignore_spaces=True, ignore_newlines=True)
+    
+    def test_posix_path(self):
+        path_list = ['foo', 'bar']
+        expected = '/'.join(path_list)
+        native = os.path.join(path_list)
+        filtered = posix_path(native)
+        self.assertEqual(filtered, expected)