"""
pygments.lexer
~~~~~~~~~~~~~~
Base lexer classes.
:copyright: Copyright 2006-2022 by the Pygments team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
import re
import sys
import time
from pygments.filter import apply_filters, Filter
from pygments.filters import get_filter_by_name
from pygments.token import Error, Text, Other, Whitespace, _TokenType
from pygments.util import get_bool_opt, get_int_opt, get_list_opt, \
make_analysator, Future, guess_decode
from pygments.regexopt import regex_opt
__all__ = ['Lexer', 'RegexLexer', 'ExtendedRegexLexer', 'DelegatingLexer',
'LexerContext', 'include', 'inherit', 'bygroups', 'using', 'this',
'default', 'words', 'line_re']
line_re = re.compile('.*?\n')
_encoding_map = [(b'\xef\xbb\xbf', 'utf-8'),
(b'\xff\xfe\0\0', 'utf-32'),
(b'\0\0\xfe\xff', 'utf-32be'),
(b'\xff\xfe', 'utf-16'),
(b'\xfe\xff', 'utf-16be')]
_default_analyse = staticmethod(lambda x: 0.0)
class LexerMeta(type):
"""
This metaclass automagically converts ``analyse_text`` methods into
static methods which always return float values.
"""
def __new__(mcs, name, bases, d):
if 'analyse_text' in d:
d['analyse_text'] = make_analysator(d['analyse_text'])
return type.__new__(mcs, name, bases, d)
class Lexer(metaclass=LexerMeta):
"""
Lexer for a specific language.
Basic options recognized:
``stripnl``
Strip leading and trailing newlines from the input (default: True).
``stripall``
Strip all leading and trailing whitespace from the input
(default: False).
``ensurenl``
Make sure that the input ends with a newline (default: True). This
is required for some lexers that consume input linewise.
.. versionadded:: 1.3
``tabsize``
If given and greater than 0, expand tabs in the input (default: 0).
``encoding``
If given, must be an encoding name. This encoding will be used to
convert the input string to Unicode, if it is not already a Unicode
string (default: ``'guess'``, which uses a simple UTF-8 / Locale /
Latin1 detection. Can also be ``'chardet'`` to use the chardet
library, if it is installed.
``inencoding``
Overrides the ``encoding`` if given.
"""
#: Name of the lexer
name = None
#: URL of the language specification/definition
url = None
#: Shortcuts for the lexer
aliases = []
#: File name globs
filenames = []
#: Secondary file name globs
alias_filenames = []
#: MIME types
mimetypes = []
#: Priority, should multiple lexers match and no content is provided
priority = 0
def __init__(self, **options):
self.options = options
self.stripnl = get_bool_opt(options, 'stripnl', True)
self.stripall = get_bool_opt(options, 'stripall', False)
self.ensurenl = get_bool_opt(options, 'ensurenl', True)
self.tabsize = get_int_opt(options, 'tabsize', 0)
self.encoding = options.get('encoding', 'guess')
self.encoding = options.get('inencoding') or self.encoding
self.filters = []
for filter_ in get_list_opt(options, 'filters', ()):
self.add_filter(filter_)
def __repr__(self):
if self.options:
return '<pygments.lexers.%s with %r>' % (self.__class__.__name__,
self.options)
else:
return '<pygments.lexers.%s>' % self.__class__.__name__
def add_filter(self, filter_, **options):
"""
Add a new stream filter to this lexer.
"""
if not isinstance(filter_, Filter):
filter_ = get_filter_by_name(filter_, **options)
self.filters.append(filter_)
def analyse_text(text):
"""
Has to return a float between ``0`` and ``1`` that indicates
if a lexer wants to highlight this text. Used by ``guess_lexer``.
If this method returns ``0`` it won't highlight it in any case, if
it returns ``1`` highlighting with this lexer is guaranteed.
The `LexerMeta` metaclass automatically wraps this function so
that it works like a static method (no ``self`` or ``cls``
parameter) and the return value is automatically converted to
`float`. If the return value is an object that is boolean `False`
it's the same as if the return values was ``0.0``.
"""
def get_tokens(self, text, unfiltered=False):
"""
Return an iterable of (tokentype, value) pairs generated from
`text`. If `unfiltered` is set to `True`, the filtering mechanism
is bypassed even if filters are defined.
Also preprocess the text, i.e. expand tabs and strip it if
wanted and applies registered filters.
"""
if not isinstance(text, str):
if self.encoding == 'guess':
text, _ = guess_decode(text)
elif self.encoding == 'chardet':
try:
import chardet
except ImportError as e:
raise ImportError('To enable chardet encoding guessing, '
'please install the chardet library '
'from http://chardet.feedparser.org/') from e
# check for BOM first
decoded = None
for bom, encoding in _encoding_map:
if text.startswith(bom):
decoded = text[len(bom):].decode(encoding, 'replace')
break
# no BOM found, so use chardet
if decoded is None:
enc = chardet.detect(text[:1024]) # Guess using first 1KB
decoded = text.decode(enc.get('encoding') or 'utf-8',
'replace')
text = decoded
else:
text = text.decode(self.encoding)
if text.startswith('\ufeff'):
text = text[len('\ufeff'):]
else:
if text.startswith('\ufeff'):
text = text[len('\ufeff'):]
# text now *is* a unicode string
text = text.replace('\r\n', '\n')
text = text.replace('\r', '\n')
if self.stripall:
text = text.strip()
elif self.stripnl:
text = text.strip('\n')
if self.tabsize > 0:
text = text.expandtabs(self.tabsize)
if self.ensurenl and not text.endswith('\n'):
text += '\n'
def streamer():
for _, t, v in self.get_tokens_unprocessed(text):
yield t, v
stream = streamer()
if not unfiltered:
stream = apply_filters(stream, self.filters, self)
return stream
def get_tokens_unprocessed(self, text):
"""
Return an iterable of (index, tokentype, value) pairs where "index"
is the starting position of the token within the input text.
In subclasses, implement this method as a generator to
maximize effectiveness.
"""
raise NotImplementedError
class DelegatingLexer(Lexer):
"""
This lexer takes two lexer as arguments. A root lexer and
a language lexer. First everything is scanned using the language
lexer, afterwards all ``Other`` tokens are lexed using the root
lexer.
The lexers from the ``template`` lexer package use this base lexer.
"""
def __init__(self, _root_lexer, _language_lexer, _needle=Other, **options):
self.root_lexer = _root_lexer(**options)
self.language_lexer = _language_lexer(**options)
self.needle = _needle
Lexer.__init__(self, **options)
def get_tokens_unprocessed(self, text):
buffered = ''
insertions = []
lng_buffer = []
for i, t, v in self.language_lexer.get_tokens_unprocessed(text):
if t is self.needle:
if lng_buffer:
insertions.append((len(buffered), lng_buffer))
lng_buffer = []
buffered += v
else:
lng_buffer.append((i, t, v))
if lng_buffer:
insertions.append((len(buffered), lng_buffer))
return do_insertions(insertions,
self.root_lexer.get_tokens_unprocessed(buffered))
# ------------------------------------------------------------------------------
# RegexLexer and ExtendedRegexLexer
#
class include(str): # pylint: disable=invalid-name
"""
Indicates that a state should include rules from another state.
"""
pass
class _inherit:
"""
Indicates the a state should inherit from its superclass.
"""
def __repr__(self):
return 'inherit'
inherit = _inherit() # pylint: disable=invalid-name
class combined(tuple): # pylint: disable=invalid-name
"""
Indicates a state combined from multiple states.
"""
def __new__(cls, *args):
return tuple.__new__(cls, args)
def __init__(self, *args):
# tuple.__init__ doesn't do anything
pass
class _PseudoMatch:
"""
A pseudo match object constructed from a string.
"""
def __init__(self, start, text):
self._text = text
self._start = start
def start(self, arg=None):
return self._start
def end(self, arg=None):
return self._start + len(self._text)
def group(self, arg=None):
if arg:
raise IndexError('No such group')
return self._text
def groups(self):
return (self._text,)
def groupdict(self):
return {}
def bygroups(*args):
"""
Callback that yields multiple actions for each group in the match.
"""
def callback(lexer, match, ctx=None):
for i, action in enumerate(args):
if action is None:
continue
elif type(action) is _TokenType:
data = match.group(i + 1)
if data:
yield match.start(i + 1), action, data
else:
data = match.group(i + 1)
if data is not None:
if ctx:
ctx.pos = match.start(i + 1)
for item in action(lexer,
_PseudoMatch(match.start(i + 1), data), ctx):
if item:
yield item
if ctx:
ctx.pos = match.end()
return callback
class _This:
"""
Special singleton used for indicating the caller class.
Used by ``using``.
"""
this = _This()
def using(_other, **kwargs):
"""
Callback that processes the match with a different lexer.
The keyword arguments are forwarded to the lexer, except `state` which
is handled separately.
`state` specifies the state that the new lexer will start in, and can
be an enumerable such as ('root', 'inline', 'string') or a simple
string which is assumed to be on top of the root state.
Note: For that to work, `_other` must not be an `ExtendedRegexLexer`.
"""
gt_kwargs = {}
if 'state' in kwargs:
s = kwargs.pop('state')
if isinstance(s, (list, tuple)):
gt_kwargs['stack'] = s
else:
gt_kwargs['stack'] = ('root', s)
if _other is this:
def callback(lexer, match, ctx=None):
# if keyword arguments are given the callback
# function has to create a new lexer instance
if kwargs:
# XXX: cache that somehow
kwargs.update(lexer.options)
lx = lexer.__class__(**kwargs)
else:
lx = lexer
s = match.start()
for i, t, v in lx.get_tokens_unprocessed(match.group(), **gt_kwargs):
yield i + s, t, v
if ctx:
ctx.pos = match.end()
else:
def callback(lexer, match, ctx=None):
# XXX: cache that somehow
kwargs.update(lexer.options)
lx = _other(**kwargs)
s = match.start()
for i, t, v in lx.get_tokens_unprocessed(match.group(), **gt_kwargs):
yield i + s, t, v
if ctx:
ctx.pos = match.end()
return callback
class default:
"""
Indicates a state or state action (e.g. #pop) to apply.
For example default('#pop') is equivalent to ('', Token, '#pop')
Note that state tuples may be used as well.
.. versionadded:: 2.0
"""
def __init__(self, state):
self.state = state
class words(Future):
"""
Indicates a list of literal words that is transformed into an optimized
regex that matches any of the words.
.. versionadded:: 2.0
"""
def __init__(self, words, prefix='', suffix=''):
self.words = words
self.prefix = prefix
self.suffix = suffix
def get(self):
return regex_opt(self.words, prefix=self.prefix, suffix=self.suffix)
class RegexLexerMeta(LexerMeta):
"""
Metaclass for RegexLexer, creates the self._tokens attribute from
self.tokens on the first instantiation.
"""
def _process_regex(cls, regex, rflags, state):
"""Preprocess the regular expression component of a token definition."""
if isinstance(regex, Future):
regex = regex.get()
return re.compile(regex, rflags).match
def _process_token(cls, token):
"""Preprocess the token component of a token definition."""
assert type(token) is _TokenType or callable(token), \
'token type must be simple type or callable, not %r' % (token,)
return token
def _process_new_state(cls, new_state, unprocessed, processed):
"""Preprocess the state transition action of a token definition."""
if isinstance(new_state, str):
# an existing state
if new_state == '#pop':
return -1
elif new_state in unprocessed:
return (new_state,)
elif new_state == '#push':
return new_state
elif new_state[:5] == '#pop:':
return -int(new_state[5:])
else:
assert False, 'unknown new state %r' % new_state
elif isinstance(new_state, combined):
# combine a new state from existing ones
tmp_state = '_tmp_%d' % cls._tmpname
cls._tmpname += 1
itokens = []
for istate in new_state:
assert istate != new_state, 'circular state ref %r' % istate
itokens.extend(cls._process_state(unprocessed,
processed, istate))
processed[tmp_state] = itokens
return (tmp_state,)
elif isinstance(new_state, tuple):
# push more than one state
for istate in new_state:
assert (istate in unprocessed or
istate in ('#pop', '#push')), \
'unknown new state ' + istate
return new_state
else:
assert False, 'unknown new state def %r' % new_state
def _process_state(cls, unprocessed, processed, state):
"""Preprocess a single state definition."""
assert type(state) is str, "wrong state name %r" % state
assert state[0] != '#', "invalid state name %r" % state
if state in processed:
return processed[state]
tokens = processed[state] = []
rflags = cls.flags
for tdef in unprocessed[state]:
if isinstance(tdef, include):
# it's a state reference
assert tdef != state, "circular state reference %r" % state
tokens.extend(cls._process_state(unprocessed, processed,
str(tdef)))
continue
if isinstance(tdef, _inherit):
# should be processed already, but may not in the case of:
# 1. the state has no counterpart in any parent
# 2. the state includes more than one 'inherit'
continue
if isinstance(tdef, default):
new_state = cls._process_new_state(tdef.state, unprocessed, processed)
tokens.append((re.compile('').match, None, new_state))
continue
assert type(tdef) is tuple, "wrong rule def %r" % tdef
try:
rex = cls._process_regex(tdef[0], rflags, state)
except Exception as err:
raise ValueError("uncompilable regex %r in state %r of %r: %s" %
(tdef[0], state, cls, err)) from err
token = cls._process_token(tdef[1])
if len(tdef) == 2:
new_state = None
else:
new_state = cls._process_new_state(tdef[2],
unprocessed, processed)
tokens.append((rex, token, new_state))
return tokens
def process_tokendef(cls, name, tokendefs=None):
"""Preprocess a dictionary of token definitions."""
processed = cls._all_tokens[name] = {}
tokendefs = tokendefs or cls.tokens[name]
for state in list(tokendefs):
cls._process_state(tokendefs, processed, state)
return processed
def get_tokendefs(cls):
"""
Merge tokens from superclasses in MRO order, returning a single tokendef
dictionary.
Any state that is not defined by a subclass will be inherited
automatically. States that *are* defined by subclasses will, by
default, override that state in the superclass. If a subclass wishes to
inherit definitions from a superclass, it can use the special value
"inherit", which will cause the superclass' state definition to be
included at that point in the state.
"""
tokens = {}
inheritable = {}
for c in cls.__mro__:
toks = c.__dict__.get('tokens', {})
for state, items in toks.items():
curitems = tokens.get(state)
if curitems is None:
# N.b. because this is assigned by reference, sufficiently
# deep hierarchies are processed incrementally (e.g. for
# A(B), B(C), C(RegexLexer), B will be premodified so X(B)
# will not see any inherits in B).
tokens[state] = items
try:
inherit_ndx = items.index(inherit)
except ValueError:
continue
inheritable[state] = inherit_ndx
continue
inherit_ndx = inheritable.pop(state, None)
if inherit_ndx is None:
continue
# Replace the "inherit" value with the items
curitems[inherit_ndx:inherit_ndx+1] = items
try:
# N.b. this is the index in items (that is, the superclass
# copy), so offset required when storing below.
new_inh_ndx = items.index(inherit)
except ValueError:
pass
else:
inheritable[state] = inherit_ndx + new_inh_ndx
return tokens
def __call__(cls, *args, **kwds):
"""Instantiate cls after preprocessing its token definitions."""
if '_tokens' not in cls.__dict__:
cls._all_tokens = {}
cls._tmpname = 0
if hasattr(cls, 'token_variants') and cls.token_variants:
# don't process yet
pass
else:
cls._tokens = cls.process_tokendef('', cls.get_tokendefs())
return type.__call__(cls, *args, **kwds)
class RegexLexer(Lexer, metaclass=RegexLexerMeta):
"""
Base for simple stateful regular expression-based lexers.
Simplifies the lexing process so that you need only
provide a list of states and regular expressions.
"""
#: Flags for compiling the regular expressions.
#: Defaults to MULTILINE.
flags = re.MULTILINE
#: At all time there is a stack of states. Initially, the stack contains
#: a single state 'root'. The top of the stack is called "the current state".
#:
#: Dict of ``{'state': [(regex, tokentype, new_state), ...], ...}``
#:
#: ``new_state`` can be omitted to signify no state transition.
#: If ``new_state`` is a string, it is pushed on the stack. This ensure
#: the new current state is ``new_state``.
#: If ``new_state`` is a tuple of strings, all of those strings are pushed
#: on the stack and the current state will be the last element of the list.
#: ``new_state`` can also be ``combined('state1', 'state2', ...)``
#: to signify a new, anonymous state combined from the rules of two
#: or more existing ones.
#: Furthermore, it can be '#pop' to signify going back one step in
#: the state stack, or '#push' to push the current state on the stack
#: again. Note that if you push while in a combined state, the combined
#: state itself is pushed, and not only the state in which the rule is
#: defined.
#:
#: The tuple can also be replaced with ``include('state')``, in which
#: case the rules from the state named by the string are included in the
#: current one.
tokens = {}
def get_tokens_unprocessed(self, text, stack=('root',)):
"""
Split ``text`` into (tokentype, text) pairs.
``stack`` is the initial stack (default: ``['root']``)
"""
pos = 0
tokendefs = self._tokens
statestack = list(stack)
statetokens = tokendefs[statestack[-1]]
while 1:
for rexmatch, action, new_state in statetokens:
m = rexmatch(text, pos)
if m:
if action is not None:
if type(action) is _TokenType:
yield pos, action, m.group()
else:
yield from action(self, m)
pos = m.end()
if new_state is not None:
# state transition
if isinstance(new_state, tuple):
for state in new_state:
if state == '#pop':
if len(statestack) > 1:
statestack.pop()
elif state == '#push':
statestack.append(statestack[-1])
else:
statestack.append(state)
elif isinstance(new_state, int):
# pop, but keep at least one state on the stack
# (random code leading to unexpected pops should
# not allow exceptions)
if abs(new_state) >= len(statestack):
del statestack[1:]
else:
del statestack[new_state:]
elif new_state == '#push':
statestack.append(statestack[-1])
else:
assert False, "wrong state def: %r" % new_state
statetokens = tokendefs[statestack[-1]]
break
else:
# We are here only if all state tokens have been considered
# and there was not a match on any of them.
try:
if text[pos] == '\n':
# at EOL, reset state to "root"
statestack = ['root']
statetokens = tokendefs['root']
yield pos, Whitespace, '\n'
pos += 1
continue
yield pos, Error, text[pos]
pos += 1
except IndexError:
break
class LexerContext:
"""
A helper object that holds lexer position data.
"""
def __init__(self, text, pos, stack=None, end=None):
self.text = text
self.pos = pos
self.end = end or len(text) # end=0 not supported ;-)
self.stack = stack or ['root']
def __repr__(self):
return 'LexerContext(%r, %r, %r)' % (
self.text, self.pos, self.stack)
class ExtendedRegexLexer(RegexLexer):
"""
A RegexLexer that uses a context object to store its state.
"""
def get_tokens_unprocessed(self, text=None, context=None):
"""
Split ``text`` into (tokentype, text) pairs.
If ``context`` is given, use this lexer context instead.
"""
tokendefs = self._tokens
if not context:
ctx = LexerContext(text, 0)
statetokens = tokendefs['root']
else:
ctx = context
statetokens = tokendefs[ctx.stack[-1]]
text = ctx.text
while 1:
for rexmatch, action, new_state in statetokens:
m = rexmatch(text, ctx.pos, ctx.end)
if m:
if action is not None:
if type(action) is _TokenType:
yield ctx.pos, action, m.group()
ctx.pos = m.end()
else:
yield from action(self, m, ctx)
if not new_state:
# altered the state stack?
statetokens = tokendefs[ctx.stack[-1]]
# CAUTION: callback must set ctx.pos!
if new_state is not None:
# state transition
if isinstance(new_state, tuple):
for state in new_state:
if state == '#pop':
if len(ctx.stack) > 1:
ctx.stack.pop()
elif state == '#push':
ctx.stack.append(ctx.stack[-1])
else:
ctx.stack.append(state)
elif isinstance(new_state, int):
# see RegexLexer for why this check is made
if abs(new_state) >= len(ctx.stack):
del ctx.stack[1:]
else:
del ctx.stack[new_state:]
elif new_state == '#push':
ctx.stack.append(ctx.stack[-1])
else:
assert False, "wrong state def: %r" % new_state
statetokens = tokendefs[ctx.stack[-1]]
break
else:
try:
if ctx.pos >= ctx.end:
break
if text[ctx.pos] == '\n':
# at EOL, reset state to "root"
ctx.stack = ['root']
statetokens = tokendefs['root']
yield ctx.pos, Text, '\n'
ctx.pos += 1
continue
yield ctx.pos, Error, text[ctx.pos]
ctx.pos += 1
except IndexError:
break
def do_insertions(insertions, tokens):
"""
Helper for lexers which must combine the results of several
sublexers.
``insertions`` is a list of ``(index, itokens)`` pairs.
Each ``itokens`` iterable should be inserted at position
``index`` into the token stream given by the ``tokens``
argument.
The result is a combined token stream.
TODO: clean up the code here.
"""
insertions = iter(insertions)
try:
index, itokens = next(insertions)
except StopIteration:
# no insertions
yield from tokens
return
realpos = None
insleft = True
# iterate over the token stream where we want to insert
# the tokens from the insertion list.
for i, t, v in tokens:
# first iteration. store the position of first item
if realpos is None:
realpos = i
oldi = 0
while insleft and i + len(v) >= index:
tmpval = v[oldi:index - i]
if tmpval:
yield realpos, t, tmpval
realpos += len(tmpval)
for it_index, it_token, it_value in itokens:
yield realpos, it_token, it_value
realpos += len(it_value)
oldi = index - i
try:
index, itokens = next(insertions)
except StopIteration:
insleft = False
break # not strictly necessary
if oldi < len(v):
yield realpos, t, v[oldi:]
realpos += len(v) - oldi
# leftover tokens
while insleft:
# no normal tokens, set realpos to zero
realpos = realpos or 0
for p, t, v in itokens:
yield realpos, t, v
realpos += len(v)
try:
index, itokens = next(insertions)
except StopIteration:
insleft = False
break # not strictly necessary
class ProfilingRegexLexerMeta(RegexLexerMeta):
"""Metaclass for ProfilingRegexLexer, collects regex timing info."""
def _process_regex(cls, regex, rflags, state):
if isinstance(regex, words):
rex = regex_opt(regex.words, prefix=regex.prefix,
suffix=regex.suffix)
else:
rex = regex
compiled = re.compile(rex, rflags)
def match_func(text, pos, endpos=sys.maxsize):
info = cls._prof_data[-1].setdefault((state, rex), [0, 0.0])
t0 = time.time()
res = compiled.match(text, pos, endpos)
t1 = time.time()
info[0] += 1
info[1] += t1 - t0
return res
return match_func
class ProfilingRegexLexer(RegexLexer, metaclass=ProfilingRegexLexerMeta):
"""Drop-in replacement for RegexLexer that does profiling of its regexes."""
_prof_data = []
_prof_sort_index = 4 # defaults to time per call
def get_tokens_unprocessed(self, text, stack=('root',)):
# this needs to be a stack, since using(this) will produce nested calls
self.__class__._prof_data.append({})
yield from RegexLexer.get_tokens_unprocessed(self, text, stack)
rawdata = self.__class__._prof_data.pop()
data = sorted(((s, repr(r).strip('u\'').replace('\\\\', '\\')[:65],
n, 1000 * t, 1000 * t / n)
for ((s, r), (n, t)) in rawdata.items()),
key=lambda x: x[self._prof_sort_index],
reverse=True)
sum_total = sum(x[3] for x in data)
print()
print('Profiling result for %s lexing %d chars in %.3f ms' %
(self.__class__.__name__, len(text), sum_total))
print('=' * 110)
print('%-20s %-64s ncalls tottime percall' % ('state', 'regex'))
print('-' * 110)
for d in data:
print('%-20s %-65s %5d %8.4f %8.4f' % d)
print('=' * 110)