pygments.filter.py Maven / Gradle / Ivy
# -*- coding: utf-8 -*-
"""
pygments.filter
~~~~~~~~~~~~~~~
Module that implements the default filter.
:copyright: Copyright 2006-2012 by the Pygments team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
def apply_filters(stream, filters, lexer=None):
"""
Use this method to apply an iterable of filters to
a stream. If lexer is given it's forwarded to the
filter, otherwise the filter receives `None`.
"""
def _apply(filter_, stream):
for token in filter_.filter(lexer, stream):
yield token
for filter_ in filters:
stream = _apply(filter_, stream)
return stream
def simplefilter(f):
"""
Decorator that converts a function into a filter::
@simplefilter
def lowercase(lexer, stream, options):
for ttype, value in stream:
yield ttype, value.lower()
"""
return type(f.__name__, (FunctionFilter,), {
'function': f,
'__module__': getattr(f, '__module__'),
'__doc__': f.__doc__
})
class Filter(object):
"""
Default filter. Subclass this class or use the `simplefilter`
decorator to create own filters.
"""
def __init__(self, **options):
self.options = options
def filter(self, lexer, stream):
raise NotImplementedError()
class FunctionFilter(Filter):
"""
Abstract class used by `simplefilter` to create simple
function filters on the fly. The `simplefilter` decorator
automatically creates subclasses of this class for
functions passed to it.
"""
function = None
def __init__(self, **options):
if not hasattr(self, 'function'):
raise TypeError('%r used without bound function' %
self.__class__.__name__)
Filter.__init__(self, **options)
def filter(self, lexer, stream):
# pylint: disable-msg=E1102
for ttype, value in self.function(lexer, stream, self.options):
yield ttype, value