Source code for mwparserfromhell.nodes.template

# Copyright (C) 2012-2020 Ben Kurtovic <ben.kurtovic@gmail.com>
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from collections import defaultdict
import re

from ._base import Node
from .html_entity import HTMLEntity
from .text import Text
from .extras import Parameter
from ..utils import parse_anything

__all__ = ["Template"]

FLAGS = re.DOTALL | re.UNICODE
# Used to allow None as a valid fallback value
_UNSET = object()


[docs]class Template(Node): """Represents a template in wikicode, like ``{{foo}}``.""" def __init__(self, name, params=None): super().__init__() self.name = name if params: self._params = params else: self._params = [] def __str__(self): if self.params: params = "|".join([str(param) for param in self.params]) return "{{" + str(self.name) + "|" + params + "}}" return "{{" + str(self.name) + "}}" def __children__(self): yield self.name for param in self.params: if param.showkey: yield param.name yield param.value def __strip__(self, **kwargs): if kwargs.get("keep_template_params"): parts = [param.value.strip_code(**kwargs) for param in self.params] return " ".join(part for part in parts if part) return None def __showtree__(self, write, get, mark): write("{{") get(self.name) for param in self.params: write(" | ") mark() get(param.name) write(" = ") mark() get(param.value) write("}}") @staticmethod def _surface_escape(code, char): """Return *code* with *char* escaped as an HTML entity. The main use of this is to escape pipes (``|``) or equal signs (``=``) in parameter names or values so they are not mistaken for new parameters. """ replacement = str(HTMLEntity(value=ord(char))) for node in code.filter_text(recursive=False): if char in node: code.replace(node, node.replace(char, replacement), False) @staticmethod def _select_theory(theories): """Return the most likely spacing convention given different options. Given a dictionary of convention options as keys and their occurrence as values, return the convention that occurs the most, or ``None`` if there is no clear preferred style. """ if theories: values = tuple(theories.values()) best = max(values) confidence = float(best) / sum(values) if confidence > 0.5: return tuple(theories.keys())[values.index(best)] return None @staticmethod def _blank_param_value(value): """Remove the content from *value* while keeping its whitespace. Replace *value*\\ 's nodes with two text nodes, the first containing whitespace from before its content and the second containing whitespace from after its content. """ sval = str(value) if sval.isspace(): before, after = "", sval else: match = re.search(r"^(\s*).*?(\s*)$", sval, FLAGS) before, after = match.group(1), match.group(2) value.nodes = [Text(before), Text(after)] def _get_spacing_conventions(self, use_names): """Try to determine the whitespace conventions for parameters. This will examine the existing parameters and use :meth:`_select_theory` to determine if there are any preferred styles for how much whitespace to put before or after the value. """ before_theories = defaultdict(lambda: 0) after_theories = defaultdict(lambda: 0) for param in self.params: if not param.showkey: continue if use_names: component = str(param.name) else: component = str(param.value) match = re.search(r"^(\s*).*?(\s*)$", component, FLAGS) before, after = match.group(1), match.group(2) if not use_names and component.isspace() and "\n" in before: # If the value is empty, we expect newlines in the whitespace # to be after the content, not before it: before, after = before.split("\n", 1) after = "\n" + after before_theories[before] += 1 after_theories[after] += 1 before = self._select_theory(before_theories) after = self._select_theory(after_theories) return before, after def _fix_dependendent_params(self, i): """Unhide keys if necessary after removing the param at index *i*.""" if not self.params[i].showkey: for param in self.params[i + 1 :]: if not param.showkey: param.showkey = True def _remove_exact(self, needle, keep_field): """Remove a specific parameter, *needle*, from the template.""" for i, param in enumerate(self.params): if param is needle: if keep_field: self._blank_param_value(param.value) else: self._fix_dependendent_params(i) self.params.pop(i) return raise ValueError(needle) def _should_remove(self, i, name): """Look ahead for a parameter with the same name, but hidden. If one exists, we should remove the given one rather than blanking it. """ if self.params[i].showkey: following = self.params[i + 1 :] better_matches = [ after.name.strip() == name and not after.showkey for after in following ] return any(better_matches) return False @property def name(self): """The name of the template, as a :class:`.Wikicode` object.""" return self._name @property def params(self): """The list of parameters contained within the template.""" return self._params @name.setter def name(self, value): self._name = parse_anything(value)
[docs] def has(self, name, ignore_empty=False): """Return ``True`` if any parameter in the template is named *name*. With *ignore_empty*, ``False`` will be returned even if the template contains a parameter with the name *name*, if the parameter's value is empty. Note that a template may have multiple parameters with the same name, but only the last one is read by the MediaWiki parser. """ name = str(name).strip() for param in self.params: if param.name.strip() == name: if ignore_empty and not param.value.strip(): continue return True return False
[docs] def has_param(self, name, ignore_empty=False): """Alias for :meth:`has`.""" return self.has(name, ignore_empty)
[docs] def get(self, name, default=_UNSET): """Get the parameter whose name is *name*. The returned object is a :class:`.Parameter` instance. Raises :exc:`ValueError` if no parameter has this name. If *default* is set, returns that instead. Since multiple parameters can have the same name, we'll return the last match, since the last parameter is the only one read by the MediaWiki parser. """ name = str(name).strip() for param in reversed(self.params): if param.name.strip() == name: return param if default is _UNSET: raise ValueError(name) return default
def __getitem__(self, name): return self.get(name)
[docs] def add(self, name, value, showkey=None, before=None, preserve_spacing=True): """Add a parameter to the template with a given *name* and *value*. *name* and *value* can be anything parsable by :func:`.utils.parse_anything`; pipes and equal signs are automatically escaped from *value* when appropriate. If *name* is already a parameter in the template, we'll replace its value. If *showkey* is given, this will determine whether or not to show the parameter's name (e.g., ``{{foo|bar}}``'s parameter has a name of ``"1"`` but it is hidden); otherwise, we'll make a safe and intelligent guess. If *before* is given (either a :class:`.Parameter` object or a name), then we will place the parameter immediately before this one. Otherwise, it will be added at the end. If *before* is a name and exists multiple times in the template, we will place it before the last occurrence. If *before* is not in the template, :exc:`ValueError` is raised. The argument is ignored if *name* is an existing parameter. If *preserve_spacing* is ``True``, we will try to preserve whitespace conventions around the parameter, whether it is new or we are updating an existing value. It is disabled for parameters with hidden keys, since MediaWiki doesn't strip whitespace in this case. """ name, value = parse_anything(name), parse_anything(value) self._surface_escape(value, "|") if self.has(name): self.remove(name, keep_field=True) existing = self.get(name) if showkey is not None: existing.showkey = showkey if not existing.showkey: self._surface_escape(value, "=") nodes = existing.value.nodes if preserve_spacing and existing.showkey: for i in range(2): # Ignore empty text nodes if not nodes[i]: nodes[i] = None existing.value = parse_anything([nodes[0], value, nodes[1]]) else: existing.value = value return existing if showkey is None: if Parameter.can_hide_key(name): int_name = int(str(name)) int_keys = set() for param in self.params: if not param.showkey: int_keys.add(int(str(param.name))) expected = min(set(range(1, len(int_keys) + 2)) - int_keys) if expected == int_name: showkey = False else: showkey = True else: showkey = True if not showkey: self._surface_escape(value, "=") if preserve_spacing and showkey: before_n, after_n = self._get_spacing_conventions(use_names=True) before_v, after_v = self._get_spacing_conventions(use_names=False) name = parse_anything([before_n, name, after_n]) value = parse_anything([before_v, value, after_v]) param = Parameter(name, value, showkey) if before: if not isinstance(before, Parameter): before = self.get(before) self.params.insert(self.params.index(before), param) else: self.params.append(param) return param
def __setitem__(self, name, value): return self.add(name, value)
[docs] def remove(self, param, keep_field=False): """Remove a parameter from the template, identified by *param*. If *param* is a :class:`.Parameter` object, it will be matched exactly, otherwise it will be treated like the *name* argument to :meth:`has` and :meth:`get`. If *keep_field* is ``True``, we will keep the parameter's name, but blank its value. Otherwise, we will remove the parameter completely. When removing a parameter with a hidden name, subsequent parameters with hidden names will be made visible. For example, removing ``bar`` from ``{{foo|bar|baz}}`` produces ``{{foo|2=baz}}`` because ``{{foo|baz}}`` is incorrect. If the parameter shows up multiple times in the template and *param* is not a :class:`.Parameter` object, we will remove all instances of it (and keep only one if *keep_field* is ``True`` - either the one with a hidden name, if it exists, or the first instance). """ if isinstance(param, Parameter): self._remove_exact(param, keep_field) return name = str(param).strip() removed = False to_remove = [] for i, par in enumerate(self.params): if par.name.strip() == name: if keep_field: if self._should_remove(i, name): to_remove.append(i) else: self._blank_param_value(par.value) keep_field = False else: self._fix_dependendent_params(i) to_remove.append(i) if not removed: removed = True if not removed: raise ValueError(name) for i in reversed(to_remove): self.params.pop(i)
def __delitem__(self, param): return self.remove(param)