# -*- coding: utf-8 -*-
"""
pygments.filters
~~~~~~~~~~~~~~~~
Module containing filter lookup functions and default
filters.
:copyright: Copyright 2006-2013 by the Pygments team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
import re
from pygments.token import String, Comment, Keyword, Name, Error, Whitespace, \
string_to_tokentype
from pygments.filter import Filter
from pygments.util import get_list_opt, get_int_opt, get_bool_opt, \
get_choice_opt, ClassNotFound, OptionError
from pygments.plugin import find_plugin_filters
[docs]def find_filter_class(filtername):
"""
Lookup a filter by name. Return None if not found.
"""
if filtername in FILTERS:
return FILTERS[filtername]
for name, cls in find_plugin_filters():
if name == filtername:
return cls
return None
[docs]def get_filter_by_name(filtername, **options):
"""
Return an instantiated filter. Options are passed to the filter
initializer if wanted. Raise a ClassNotFound if not found.
"""
cls = find_filter_class(filtername)
if cls:
return cls(**options)
else:
raise ClassNotFound('filter %r not found' % filtername)
[docs]def get_all_filters():
"""
Return a generator of all filter names.
"""
for name in FILTERS:
yield name
for name, _ in find_plugin_filters():
yield name
def _replace_special(ttype, value, regex, specialttype,
replacefunc=lambda x: x):
last = 0
for match in regex.finditer(value):
start, end = match.start(), match.end()
if start != last:
yield ttype, value[last:start]
yield specialttype, replacefunc(value[start:end])
last = end
if last != len(value):
yield ttype, value[last:]
[docs]class CodeTagFilter(Filter):
"""
Highlight special code tags in comments and docstrings.
Options accepted:
`codetags` : list of strings
A list of strings that are flagged as code tags. The default is to
highlight ``XXX``, ``TODO``, ``BUG`` and ``NOTE``.
"""
def __init__(self, **options):
Filter.__init__(self, **options)
tags = get_list_opt(options, 'codetags',
['XXX', 'TODO', 'BUG', 'NOTE'])
self.tag_re = re.compile(r'\b(%s)\b' % '|'.join([
re.escape(tag) for tag in tags if tag
]))
def filter(self, lexer, stream):
regex = self.tag_re
for ttype, value in stream:
if ttype in String.Doc or \
ttype in Comment and \
ttype not in Comment.Preproc:
for sttype, svalue in _replace_special(ttype, value, regex,
Comment.Special):
yield sttype, svalue
else:
yield ttype, value
[docs]class KeywordCaseFilter(Filter):
"""
Convert keywords to lowercase or uppercase or capitalize them, which
means first letter uppercase, rest lowercase.
This can be useful e.g. if you highlight Pascal code and want to adapt the
code to your styleguide.
Options accepted:
`case` : string
The casing to convert keywords to. Must be one of ``'lower'``,
``'upper'`` or ``'capitalize'``. The default is ``'lower'``.
"""
def __init__(self, **options):
Filter.__init__(self, **options)
case = get_choice_opt(options, 'case', ['lower', 'upper', 'capitalize'], 'lower')
self.convert = getattr(unicode, case)
def filter(self, lexer, stream):
for ttype, value in stream:
if ttype in Keyword:
yield ttype, self.convert(value)
else:
yield ttype, value
[docs]class NameHighlightFilter(Filter):
"""
Highlight a normal Name token with a different token type.
Example::
filter = NameHighlightFilter(
names=['foo', 'bar', 'baz'],
tokentype=Name.Function,
)
This would highlight the names "foo", "bar" and "baz"
as functions. `Name.Function` is the default token type.
Options accepted:
`names` : list of strings
A list of names that should be given the different token type.
There is no default.
`tokentype` : TokenType or string
A token type or a string containing a token type name that is
used for highlighting the strings in `names`. The default is
`Name.Function`.
"""
def __init__(self, **options):
Filter.__init__(self, **options)
self.names = set(get_list_opt(options, 'names', []))
tokentype = options.get('tokentype')
if tokentype:
self.tokentype = string_to_tokentype(tokentype)
else:
self.tokentype = Name.Function
def filter(self, lexer, stream):
for ttype, value in stream:
if ttype is Name and value in self.names:
yield self.tokentype, value
else:
yield ttype, value
class ErrorToken(Exception):
pass
[docs]class RaiseOnErrorTokenFilter(Filter):
"""
Raise an exception when the lexer generates an error token.
Options accepted:
`excclass` : Exception class
The exception class to raise.
The default is `pygments.filters.ErrorToken`.
*New in Pygments 0.8.*
"""
def __init__(self, **options):
Filter.__init__(self, **options)
self.exception = options.get('excclass', ErrorToken)
try:
# issubclass() will raise TypeError if first argument is not a class
if not issubclass(self.exception, Exception):
raise TypeError
except TypeError:
raise OptionError('excclass option is not an exception class')
def filter(self, lexer, stream):
for ttype, value in stream:
if ttype is Error:
raise self.exception(value)
yield ttype, value
[docs]class VisibleWhitespaceFilter(Filter):
"""
Convert tabs, newlines and/or spaces to visible characters.
Options accepted:
`spaces` : string or bool
If this is a one-character string, spaces will be replaces by this string.
If it is another true value, spaces will be replaced by ``·`` (unicode
MIDDLE DOT). If it is a false value, spaces will not be replaced. The
default is ``False``.
`tabs` : string or bool
The same as for `spaces`, but the default replacement character is ``»``
(unicode RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK). The default value
is ``False``. Note: this will not work if the `tabsize` option for the
lexer is nonzero, as tabs will already have been expanded then.
`tabsize` : int
If tabs are to be replaced by this filter (see the `tabs` option), this
is the total number of characters that a tab should be expanded to.
The default is ``8``.
`newlines` : string or bool
The same as for `spaces`, but the default replacement character is ``¶``
(unicode PILCROW SIGN). The default value is ``False``.
`wstokentype` : bool
If true, give whitespace the special `Whitespace` token type. This allows
styling the visible whitespace differently (e.g. greyed out), but it can
disrupt background colors. The default is ``True``.
*New in Pygments 0.8.*
"""
def __init__(self, **options):
Filter.__init__(self, **options)
for name, default in {'spaces': u'·', 'tabs': u'»', 'newlines': u'¶'}.items():
opt = options.get(name, False)
if isinstance(opt, basestring) and len(opt) == 1:
setattr(self, name, opt)
else:
setattr(self, name, (opt and default or ''))
tabsize = get_int_opt(options, 'tabsize', 8)
if self.tabs:
self.tabs += ' '*(tabsize-1)
if self.newlines:
self.newlines += '\n'
self.wstt = get_bool_opt(options, 'wstokentype', True)
def filter(self, lexer, stream):
if self.wstt:
spaces = self.spaces or ' '
tabs = self.tabs or '\t'
newlines = self.newlines or '\n'
regex = re.compile(r'\s')
def replacefunc(wschar):
if wschar == ' ':
return spaces
elif wschar == '\t':
return tabs
elif wschar == '\n':
return newlines
return wschar
for ttype, value in stream:
for sttype, svalue in _replace_special(ttype, value, regex,
Whitespace, replacefunc):
yield sttype, svalue
else:
spaces, tabs, newlines = self.spaces, self.tabs, self.newlines
# simpler processing
for ttype, value in stream:
if spaces:
value = value.replace(' ', spaces)
if tabs:
value = value.replace('\t', tabs)
if newlines:
value = value.replace('\n', newlines)
yield ttype, value
[docs]class GobbleFilter(Filter):
"""
Gobbles source code lines (eats initial characters).
This filter drops the first ``n`` characters off every line of code. This
may be useful when the source code fed to the lexer is indented by a fixed
amount of space that isn't desired in the output.
Options accepted:
`n` : int
The number of characters to gobble.
*New in Pygments 1.2.*
"""
def __init__(self, **options):
Filter.__init__(self, **options)
self.n = get_int_opt(options, 'n', 0)
def gobble(self, value, left):
if left < len(value):
return value[left:], 0
else:
return '', left - len(value)
def filter(self, lexer, stream):
n = self.n
left = n # How many characters left to gobble.
for ttype, value in stream:
# Remove ``left`` tokens from first line, ``n`` from all others.
parts = value.split('\n')
(parts[0], left) = self.gobble(parts[0], left)
for i in range(1, len(parts)):
(parts[i], left) = self.gobble(parts[i], n)
value = '\n'.join(parts)
if value != '':
yield ttype, value
[docs]class TokenMergeFilter(Filter):
"""
Merges consecutive tokens with the same token type in the output stream of a
lexer.
*New in Pygments 1.2.*
"""
def __init__(self, **options):
Filter.__init__(self, **options)
def filter(self, lexer, stream):
current_type = None
current_value = None
for ttype, value in stream:
if ttype is current_type:
current_value += value
else:
if current_type is not None:
yield current_type, current_value
current_type = ttype
current_value = value
if current_type is not None:
yield current_type, current_value
FILTERS = {
'codetagify': CodeTagFilter,
'keywordcase': KeywordCaseFilter,
'highlight': NameHighlightFilter,
'raiseonerror': RaiseOnErrorTokenFilter,
'whitespace': VisibleWhitespaceFilter,
'gobble': GobbleFilter,
'tokenmerge': TokenMergeFilter,
}