Fix bug in ipy_pretty extension.

See: https://bugs.launchpad.net/debian/+source/ipython/+bug/504031

IPython/Extensions/ipy_pretty.py

@@ -1,132 +1,132 b''
 """ Use pretty.py for configurable pretty-printing.
 
 Register pretty-printers for types using ipy_pretty.for_type() or
 ipy_pretty.for_type_by_name(). For example, to use the example pretty-printer
 for numpy dtype objects, add the following to your ipy_user_conf.py::
 
     from IPython.Extensions import ipy_pretty
 
     ipy_pretty.activate()
 
     # If you want to have numpy always imported anyways:
     import numpy
     ipy_pretty.for_type(numpy.dtype, ipy_pretty.dtype_pprinter)
 
     # If you don't want to have numpy imported until it needs to be:
     ipy_pretty.for_type_by_name('numpy', 'dtype', ipy_pretty.dtype_pprinter)
 """
 
 import IPython.ipapi
 from IPython.genutils import Term
 
 from IPython.external import pretty
 
 ip = IPython.ipapi.get()
 
 
 #### Implementation ############################################################
 
 def pretty_result_display(self, arg):
     """ Uber-pretty-printing display hook.
 
     Called for displaying the result to the user.
     """
     
     if ip.options.pprint:
         verbose = getattr(ip.options, 'pretty_verbose', False)
         out = pretty.pretty(arg, verbose=verbose)
         if '\n' in out:
             # So that multi-line strings line up with the left column of
             # the screen, instead of having the output prompt mess up
             # their first line.                
             Term.cout.write('\n')
         print >>Term.cout, out
     else:
-        raise TryNext
+        raise IPython.ipapi.TryNext
 
 
 #### API #######################################################################
 
 # Expose the for_type and for_type_by_name functions for easier use.
 for_type = pretty.for_type
 for_type_by_name = pretty.for_type_by_name
 
 
 # FIXME: write deactivate(). We need a way to remove a hook.
 def activate():
     """ Activate this extension.
     """
     ip.set_hook('result_display', pretty_result_display, priority=99)
 
 
 #### Example pretty-printers ###################################################
 
 def dtype_pprinter(obj, p, cycle):
     """ A pretty-printer for numpy dtype objects.
     """
     if cycle:
         return p.text('dtype(...)')
     if obj.fields is None:
         p.text(repr(obj))
     else:
         p.begin_group(7, 'dtype([')
         for i, field in enumerate(obj.descr):
             if i > 0:
                 p.text(',')
                 p.breakable()
             p.pretty(field)
         p.end_group(7, '])')
 
 
 #### Tests #####################################################################
 
 def test_pretty():
     """
     In [1]: from IPython.Extensions import ipy_pretty
 
     In [2]: ipy_pretty.activate()
 
     In [3]: class A(object):
        ...:     def __repr__(self):
        ...:         return 'A()'
        ...:     
        ...:     
 
     In [4]: a = A()
 
     In [5]: a
     Out[5]: A()
 
     In [6]: def a_pretty_printer(obj, p, cycle):
        ...:     p.text('<A>')
        ...:     
        ...:     
 
     In [7]: ipy_pretty.for_type(A, a_pretty_printer)
 
     In [8]: a
     Out[8]: <A>
 
     In [9]: class B(object):
        ...:     def __repr__(self):
        ...:         return 'B()'
        ...:     
        ...:     
 
     In [10]: B.__module__, B.__name__
     Out[10]: ('__main__', 'B')
 
     In [11]: def b_pretty_printer(obj, p, cycle):
        ....:     p.text('<B>')
        ....:     
        ....:     
 
     In [12]: ipy_pretty.for_type_by_name('__main__', 'B', b_pretty_printer)
 
     In [13]: b = B()
 
     In [14]: b
     Out[14]: <B>
     """
     assert False, "This should only be doctested, not run."