Source code for mwparserfromhell.parser.builder

# Copyright (C) 2012-2020 Ben Kurtovic <ben.kurtovic@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


from . import tokens
from .errors import ParserError
from ..nodes import (
    Argument,
    Comment,
    ExternalLink,
    Heading,
    HTMLEntity,
    Tag,
    Template,
    Text,
    Wikilink,
)
from ..nodes.extras import Attribute, Parameter
from ..smart_list import SmartList
from ..wikicode import Wikicode

__all__ = ["Builder"]

_HANDLERS = {tokens.Text: lambda self, token: Text(token.text)}


def _add_handler(token_type):
    """Create a decorator that adds a handler function to the lookup table."""

    def decorator(func):
        """Add a handler function to the lookup table."""
        _HANDLERS[token_type] = func
        return func

    return decorator


[docs]class Builder: """Builds a tree of nodes out of a sequence of tokens. To use, pass a list of :class:`.Token`\\ s to the :meth:`build` method. The list will be exhausted as it is parsed and a :class:`.Wikicode` object containing the node tree will be returned. """ def __init__(self): self._tokens = [] self._stacks = []
[docs] def _push(self): """Push a new node list onto the stack.""" self._stacks.append([])
[docs] def _pop(self): """Pop the current node list off of the stack. The raw node list is wrapped in a :class:`.SmartList` and then in a :class:`.Wikicode` object. """ return Wikicode(SmartList(self._stacks.pop()))
[docs] def _write(self, item): """Append a node to the current node list.""" self._stacks[-1].append(item)
[docs] def _handle_parameter(self, default): """Handle a case where a parameter is at the head of the tokens. *default* is the value to use if no parameter name is defined. """ key = None showkey = False self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.TemplateParamEquals): key = self._pop() showkey = True self._push() elif isinstance( token, (tokens.TemplateParamSeparator, tokens.TemplateClose) ): self._tokens.append(token) value = self._pop() if key is None: key = Wikicode(SmartList([Text(str(default))])) return Parameter(key, value, showkey) else: self._write(self._handle_token(token)) raise ParserError("_handle_parameter() missed a close token")
[docs] @_add_handler(tokens.TemplateOpen) def _handle_template(self, token): """Handle a case where a template is at the head of the tokens.""" params = [] default = 1 self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.TemplateParamSeparator): if not params: name = self._pop() param = self._handle_parameter(default) params.append(param) if not param.showkey: default += 1 elif isinstance(token, tokens.TemplateClose): if not params: name = self._pop() return Template(name, params) else: self._write(self._handle_token(token)) raise ParserError("_handle_template() missed a close token")
[docs] @_add_handler(tokens.ArgumentOpen) def _handle_argument(self, token): """Handle a case where an argument is at the head of the tokens.""" name = None self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.ArgumentSeparator): name = self._pop() self._push() elif isinstance(token, tokens.ArgumentClose): if name is not None: return Argument(name, self._pop()) return Argument(self._pop()) else: self._write(self._handle_token(token)) raise ParserError("_handle_argument() missed a close token")
[docs] @_add_handler(tokens.HTMLEntityStart) def _handle_entity(self, token): """Handle a case where an HTML entity is at the head of the tokens.""" token = self._tokens.pop() if isinstance(token, tokens.HTMLEntityNumeric): token = self._tokens.pop() if isinstance(token, tokens.HTMLEntityHex): text = self._tokens.pop() self._tokens.pop() # Remove HTMLEntityEnd return HTMLEntity( text.text, named=False, hexadecimal=True, hex_char=token.char ) self._tokens.pop() # Remove HTMLEntityEnd return HTMLEntity(token.text, named=False, hexadecimal=False) self._tokens.pop() # Remove HTMLEntityEnd return HTMLEntity(token.text, named=True, hexadecimal=False)
[docs] @_add_handler(tokens.HeadingStart) def _handle_heading(self, token): """Handle a case where a heading is at the head of the tokens.""" level = token.level self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.HeadingEnd): title = self._pop() return Heading(title, level) self._write(self._handle_token(token)) raise ParserError("_handle_heading() missed a close token")
[docs] @_add_handler(tokens.CommentStart) def _handle_comment(self, token): """Handle a case where an HTML comment is at the head of the tokens.""" self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.CommentEnd): contents = self._pop() return Comment(contents) self._write(self._handle_token(token)) raise ParserError("_handle_comment() missed a close token")
[docs] def _handle_attribute(self, start): """Handle a case where a tag attribute is at the head of the tokens.""" name = quotes = None self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.TagAttrEquals): name = self._pop() self._push() elif isinstance(token, tokens.TagAttrQuote): quotes = token.char elif isinstance( token, (tokens.TagAttrStart, tokens.TagCloseOpen, tokens.TagCloseSelfclose), ): self._tokens.append(token) if name: value = self._pop() else: name, value = self._pop(), None return Attribute( name, value, quotes, start.pad_first, start.pad_before_eq, start.pad_after_eq, ) else: self._write(self._handle_token(token)) raise ParserError("_handle_attribute() missed a close token")
[docs] @_add_handler(tokens.TagOpenOpen) def _handle_tag(self, token): """Handle a case where a tag is at the head of the tokens.""" close_tokens = (tokens.TagCloseSelfclose, tokens.TagCloseClose) implicit, attrs, contents, closing_tag = False, [], None, None wiki_markup, invalid = token.wiki_markup, token.invalid or False wiki_style_separator, closing_wiki_markup = None, wiki_markup self._push() while self._tokens: token = self._tokens.pop() if isinstance(token, tokens.TagAttrStart): attrs.append(self._handle_attribute(token)) elif isinstance(token, tokens.TagCloseOpen): wiki_style_separator = token.wiki_markup padding = token.padding or "" tag = self._pop() self._push() elif isinstance(token, tokens.TagOpenClose): closing_wiki_markup = token.wiki_markup contents = self._pop() self._push() elif isinstance(token, close_tokens): if isinstance(token, tokens.TagCloseSelfclose): closing_wiki_markup = token.wiki_markup tag = self._pop() self_closing = True padding = token.padding or "" implicit = token.implicit or False else: self_closing = False closing_tag = self._pop() return Tag( tag, contents, attrs, wiki_markup, self_closing, invalid, implicit, padding, closing_tag, wiki_style_separator, closing_wiki_markup, ) else: self._write(self._handle_token(token)) raise ParserError("_handle_tag() missed a close token")
[docs] def _handle_token(self, token): """Handle a single token.""" try: return _HANDLERS[type(token)](self, token) except KeyError: err = "_handle_token() got unexpected {0}" raise ParserError(err.format(type(token).__name__)) from None
[docs] def build(self, tokenlist): """Build a Wikicode object from a list tokens and return it.""" self._tokens = tokenlist self._tokens.reverse() self._push() while self._tokens: node = self._handle_token(self._tokens.pop()) self._write(node) return self._pop()
del _add_handler