Current File : //proc/self/root/usr/lib/python3/dist-packages/pygments/lexer.py
"""
    pygments.lexer
    ~~~~~~~~~~~~~~

    Base lexer classes.

    :copyright: Copyright 2006-2023 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.

    See also :doc:`lexerdevelopment`, a high-level guide to writing
    lexers.

    Lexer classes have attributes used for choosing the most appropriate
    lexer based on various criteria.

    .. autoattribute:: name
       :no-value:
    .. autoattribute:: aliases
       :no-value:
    .. autoattribute:: filenames
       :no-value:
    .. autoattribute:: alias_filenames
    .. autoattribute:: mimetypes
       :no-value:
    .. autoattribute:: priority

    Lexers included in Pygments should have an additional attribute:

    .. autoattribute:: url
       :no-value:

    Lexers included in Pygments may have additional attributes:

    .. autoattribute:: _example
       :no-value:

    You can pass options to the constructor. The basic options recognized
    by all lexers and processed by the base `Lexer` class are:

    ``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.
    """

    #: Full name of the lexer, in human-readable form
    name = None

    #: A list of short, unique identifiers that can be used to look
    #: up the lexer from a list, e.g., using `get_lexer_by_name()`.
    aliases = []

    #: A list of `fnmatch` patterns that match filenames which contain
    #: content for this lexer. The patterns in this list should be unique among
    #: all lexers.
    filenames = []

    #: A list of `fnmatch` patterns that match filenames which may or may not
    #: contain content for this lexer. This list is used by the
    #: :func:`.guess_lexer_for_filename()` function, to determine which lexers
    #: are then included in guessing the correct one. That means that
    #: e.g. every lexer for HTML and a template language should include
    #: ``\*.html`` in this list.
    alias_filenames = []

    #: A list of MIME types for content that can be lexed with this lexer.
    mimetypes = []

    #: Priority, should multiple lexers match and no content is provided
    priority = 0

    #: URL of the language specification/definition. Used in the Pygments
    #: documentation.
    url = None

    #: Example file name. Relative to the ``tests/examplefiles`` directory.
    #: This is used by the documentation generator to show an example.
    _example = None

    def __init__(self, **options):
        """
        This constructor takes arbitrary options as keyword arguments.
        Every subclass must first process its own options and then call
        the `Lexer` constructor, since it processes the basic
        options like `stripnl`.

        An example looks like this:

        .. sourcecode:: python

           def __init__(self, **options):
               self.compress = options.get('compress', '')
               Lexer.__init__(self, **options)

        As these options must all be specifiable as strings (due to the
        command line usage), there are various utility functions
        available to help with that, see `Utilities`_.
        """
        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):
        """
        A static method which is called for lexer guessing.

        It should analyse the text and return a float in the range
        from ``0.0`` to ``1.0``.  If it returns ``0.0``, the lexer
        will not be selected as the most probable one, if it returns
        ``1.0``, it will be selected immediately.  This is used by
        `guess_lexer`.

        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 _preprocess_lexer_input(self, text):
        """Apply preprocessing such as decoding the input, removing BOM and normalizing newlines."""

        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'

        return text

    def get_tokens(self, text, unfiltered=False):
        """
        This method is the basic interface of a lexer. It is called by
        the `highlight()` function. It must process the text and return an
        iterable of ``(tokentype, value)`` pairs from `text`.

        Normally, you don't need to override this method. The default
        implementation processes the options recognized by all lexers
        (`stripnl`, `stripall` and so on), and then yields all tokens
        from `get_tokens_unprocessed()`, with the ``index`` dropped.

        If `unfiltered` is set to `True`, the filtering mechanism is
        bypassed even if filters are defined.
        """
        text = self._preprocess_lexer_input(text)

        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):
        """
        This method should process the text and return an iterable of
        ``(index, tokentype, value)`` tuples where ``index`` is the starting
        position of the token within the input text.

        It must be overridden by subclasses. It is recommended to
        implement it 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)
¿Qué es la limpieza dental de perros? - Clínica veterinaria


Es la eliminación del sarro y la placa adherida a la superficie de los dientes mediante un equipo de ultrasonidos que garantiza la integridad de las piezas dentales a la vez que elimina en profundidad cualquier resto de suciedad.

A continuación se procede al pulido de los dientes mediante una fresa especial que elimina la placa bacteriana y devuelve a los dientes el aspecto sano que deben tener.

Una vez terminado todo el proceso, se mantiene al perro en observación hasta que se despierta de la anestesia, bajo la atenta supervisión de un veterinario.

¿Cada cuánto tiempo tengo que hacerle una limpieza dental a mi perro?

A partir de cierta edad, los perros pueden necesitar una limpieza dental anual o bianual. Depende de cada caso. En líneas generales, puede decirse que los perros de razas pequeñas suelen acumular más sarro y suelen necesitar una atención mayor en cuanto a higiene dental.


Riesgos de una mala higiene


Los riesgos más evidentes de una mala higiene dental en los perros son los siguientes:

  • Cuando la acumulación de sarro no se trata, se puede producir una inflamación y retracción de las encías que puede descalzar el diente y provocar caídas.
  • Mal aliento (halitosis).
  • Sarro perros
  • Puede ir a más
  • Las bacterias de la placa pueden trasladarse a través del torrente circulatorio a órganos vitales como el corazón ocasionando problemas de endocarditis en las válvulas. Las bacterias pueden incluso acantonarse en huesos (La osteomielitis es la infección ósea, tanto cortical como medular) provocando mucho dolor y una artritis séptica).

¿Cómo se forma el sarro?

El sarro es la calcificación de la placa dental. Los restos de alimentos, junto con las bacterias presentes en la boca, van a formar la placa bacteriana o placa dental. Si la placa no se retira, al mezclarse con la saliva y los minerales presentes en ella, reaccionará formando una costra. La placa se calcifica y se forma el sarro.

El sarro, cuando se forma, es de color blanquecino pero a medida que pasa el tiempo se va poniendo amarillo y luego marrón.

Síntomas de una pobre higiene dental
La señal más obvia de una mala salud dental canina es el mal aliento.

Sin embargo, a veces no es tan fácil de detectar
Y hay perros que no se dejan abrir la boca por su dueño. Por ejemplo…

Recientemente nos trajeron a la clínica a un perro que parpadeaba de un ojo y decía su dueño que le picaba un lado de la cara. Tenía molestias y dificultad para comer, lo que había llevado a sus dueños a comprarle comida blanda (que suele ser un poco más cara y llevar más contenido en grasa) durante medio año. Después de una exploración oftalmológica, nos dimos cuenta de que el ojo tenía una úlcera en la córnea probablemente de rascarse . Además, el canto lateral del ojo estaba inflamado. Tenía lo que en humanos llamamos flemón pero como era un perro de pelo largo, no se le notaba a simple vista. Al abrirle la boca nos llamó la atención el ver una muela llena de sarro. Le realizamos una radiografía y encontramos una fístula que llegaba hasta la parte inferior del ojo.

Le tuvimos que extraer la muela. Tras esto, el ojo se curó completamente con unos colirios y una lentilla protectora de úlcera. Afortunadamente, la úlcera no profundizó y no perforó el ojo. Ahora el perro come perfectamente a pesar de haber perdido una muela.

¿Cómo mantener la higiene dental de tu perro?
Hay varias maneras de prevenir problemas derivados de la salud dental de tu perro.

Limpiezas de dientes en casa
Es recomendable limpiar los dientes de tu perro semanal o diariamente si se puede. Existe una gran variedad de productos que se pueden utilizar:

Pastas de dientes.
Cepillos de dientes o dedales para el dedo índice, que hacen más fácil la limpieza.
Colutorios para echar en agua de bebida o directamente sobre el diente en líquido o en spray.

En la Clínica Tus Veterinarios enseñamos a nuestros clientes a tomar el hábito de limpiar los dientes de sus perros desde que son cachorros. Esto responde a nuestro compromiso con la prevención de enfermedades caninas.

Hoy en día tenemos muchos clientes que limpian los dientes todos los días a su mascota, y como resultado, se ahorran el dinero de hacer limpiezas dentales profesionales y consiguen una mejor salud de su perro.


Limpiezas dentales profesionales de perros y gatos

Recomendamos hacer una limpieza dental especializada anualmente. La realizamos con un aparato de ultrasonidos que utiliza agua para quitar el sarro. Después, procedemos a pulir los dientes con un cepillo de alta velocidad y una pasta especial. Hacemos esto para proteger el esmalte.

La frecuencia de limpiezas dentales necesaria varía mucho entre razas. En general, las razas grandes tienen buena calidad de esmalte, por lo que no necesitan hacerlo tan a menudo e incluso pueden pasarse la vida sin requerir una limpieza. Sin embargo, razas pequeñas como el Yorkshire o el Maltés, deben hacérselas todos los años desde cachorros si se quiere conservar sus piezas dentales.

Otro factor fundamental es la calidad del pienso. Algunas marcas han diseñado croquetas que limpian la superficie del diente y de la muela al masticarse.

Ultrasonido para perros

¿Se necesita anestesia para las limpiezas dentales de perros y gatos?

La limpieza dental en perros no es una técnica que pueda practicarse sin anestesia general , aunque hay veces que los propietarios no quieren anestesiar y si tiene poco sarro y el perro es muy bueno se puede intentar…… , pero no se va a poder pulir ni acceder a todas la zona de la boca …. Además los limpiadores dentales van a irrigar agua y hay riesgo de aspiración a vías respiratorias si no se realiza una anestesia correcta con intubación traqueal . En resumen , sin anestesia no se va hacer una correcta limpieza dental.

Tampoco sirve la sedación ya que necesitamos que el animal esté totalmente quieto, y el veterinario tenga un acceso completo a todas sus piezas dentales y encías.

Alimentos para la limpieza dental

Hay que tener cierto cuidado a la hora de comprar determinados alimentos porque no todos son saludables. Algunos tienen demasiado contenido graso, que en exceso puede causar problemas cardiovasculares y obesidad.

Los mejores alimentos para los dientes son aquellos que están elaborados por empresas farmacéuticas y llevan componentes químicos con tratamientos específicos para el diente del perro. Esto implica no solo limpieza a través de la acción mecánica de morder sino también un tratamiento antibacteriano para prevenir el sarro.

Conclusión

Si eres como la mayoría de dueños, por falta de tiempo , es probable que no estés prestando la suficiente atención a la limpieza dental de tu perro. Por eso te animamos a que comiences a limpiar los dientes de tu perro y consideres atender a su higiene bucal con frecuencia.

Estas simples medidas pueden conllevar a que tu perro tenga una vida más larga y mucho más saludable.

Si te resulta imposible introducir un cepillo de dientes a tu perro en la boca, pásate con él por clínica Tus Veterinarios y te explicamos cómo hacerlo.

Necesitas hacer una limpieza dental profesional a tu mascota?
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