forked from varia/varia.website
400 lines
15 KiB
Python
400 lines
15 KiB
Python
# $Id: roles.py 8347 2019-08-26 12:12:02Z milde $
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# Author: Edward Loper <edloper@gradient.cis.upenn.edu>
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# Copyright: This module has been placed in the public domain.
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"""
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This module defines standard interpreted text role functions, a registry for
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interpreted text roles, and an API for adding to and retrieving from the
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registry.
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The interface for interpreted role functions is as follows::
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def role_fn(name, rawtext, text, lineno, inliner,
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options={}, content=[]):
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code...
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# Set function attributes for customization:
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role_fn.options = ...
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role_fn.content = ...
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Parameters:
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- ``name`` is the local name of the interpreted text role, the role name
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actually used in the document.
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- ``rawtext`` is a string containing the entire interpreted text construct.
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Return it as a ``problematic`` node linked to a system message if there is a
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problem.
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- ``text`` is the interpreted text content, with backslash escapes converted
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to nulls (``\x00``).
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- ``lineno`` is the line number where the interpreted text beings.
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- ``inliner`` is the Inliner object that called the role function.
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It defines the following useful attributes: ``reporter``,
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``problematic``, ``memo``, ``parent``, ``document``.
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- ``options``: A dictionary of directive options for customization, to be
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interpreted by the role function. Used for additional attributes for the
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generated elements and other functionality.
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- ``content``: A list of strings, the directive content for customization
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("role" directive). To be interpreted by the role function.
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Function attributes for customization, interpreted by the "role" directive:
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- ``options``: A dictionary, mapping known option names to conversion
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functions such as `int` or `float`. ``None`` or an empty dict implies no
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options to parse. Several directive option conversion functions are defined
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in the `directives` module.
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All role functions implicitly support the "class" option, unless disabled
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with an explicit ``{'class': None}``.
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- ``content``: A boolean; true if content is allowed. Client code must handle
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the case where content is required but not supplied (an empty content list
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will be supplied).
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Note that unlike directives, the "arguments" function attribute is not
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supported for role customization. Directive arguments are handled by the
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"role" directive itself.
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Interpreted role functions return a tuple of two values:
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- A list of nodes which will be inserted into the document tree at the
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point where the interpreted role was encountered (can be an empty
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list).
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- A list of system messages, which will be inserted into the document tree
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immediately after the end of the current inline block (can also be empty).
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"""
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__docformat__ = 'reStructuredText'
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from docutils import nodes, utils
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from docutils.parsers.rst import directives
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from docutils.parsers.rst.languages import en as _fallback_language_module
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from docutils.utils.code_analyzer import Lexer, LexerError
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DEFAULT_INTERPRETED_ROLE = 'title-reference'
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"""
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The canonical name of the default interpreted role. This role is used
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when no role is specified for a piece of interpreted text.
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"""
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_role_registry = {}
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"""Mapping of canonical role names to role functions. Language-dependent role
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names are defined in the ``language`` subpackage."""
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_roles = {}
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"""Mapping of local or language-dependent interpreted text role names to role
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functions."""
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def role(role_name, language_module, lineno, reporter):
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"""
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Locate and return a role function from its language-dependent name, along
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with a list of system messages. If the role is not found in the current
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language, check English. Return a 2-tuple: role function (``None`` if the
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named role cannot be found) and a list of system messages.
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"""
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normname = role_name.lower()
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messages = []
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msg_text = []
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if normname in _roles:
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return _roles[normname], messages
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if role_name:
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canonicalname = None
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try:
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canonicalname = language_module.roles[normname]
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except AttributeError as error:
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msg_text.append('Problem retrieving role entry from language '
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'module %r: %s.' % (language_module, error))
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except KeyError:
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msg_text.append('No role entry for "%s" in module "%s".'
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% (role_name, language_module.__name__))
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else:
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canonicalname = DEFAULT_INTERPRETED_ROLE
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# If we didn't find it, try English as a fallback.
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if not canonicalname:
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try:
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canonicalname = _fallback_language_module.roles[normname]
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msg_text.append('Using English fallback for role "%s".'
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% role_name)
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except KeyError:
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msg_text.append('Trying "%s" as canonical role name.'
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% role_name)
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# The canonical name should be an English name, but just in case:
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canonicalname = normname
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# Collect any messages that we generated.
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if msg_text:
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message = reporter.info('\n'.join(msg_text), line=lineno)
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messages.append(message)
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# Look the role up in the registry, and return it.
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if canonicalname in _role_registry:
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role_fn = _role_registry[canonicalname]
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register_local_role(normname, role_fn)
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return role_fn, messages
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else:
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return None, messages # Error message will be generated by caller.
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def register_canonical_role(name, role_fn):
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"""
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Register an interpreted text role by its canonical name.
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:Parameters:
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- `name`: The canonical name of the interpreted role.
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- `role_fn`: The role function. See the module docstring.
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"""
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set_implicit_options(role_fn)
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_role_registry[name] = role_fn
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def register_local_role(name, role_fn):
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"""
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Register an interpreted text role by its local or language-dependent name.
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:Parameters:
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- `name`: The local or language-dependent name of the interpreted role.
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- `role_fn`: The role function. See the module docstring.
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"""
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set_implicit_options(role_fn)
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_roles[name] = role_fn
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def set_implicit_options(role_fn):
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"""
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Add customization options to role functions, unless explicitly set or
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disabled.
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"""
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if not hasattr(role_fn, 'options') or role_fn.options is None:
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role_fn.options = {'class': directives.class_option}
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elif 'class' not in role_fn.options:
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role_fn.options['class'] = directives.class_option
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def register_generic_role(canonical_name, node_class):
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"""For roles which simply wrap a given `node_class` around the text."""
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role = GenericRole(canonical_name, node_class)
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register_canonical_role(canonical_name, role)
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class GenericRole(object):
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"""
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Generic interpreted text role, where the interpreted text is simply
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wrapped with the provided node class.
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"""
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def __init__(self, role_name, node_class):
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self.name = role_name
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self.node_class = node_class
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def __call__(self, role, rawtext, text, lineno, inliner,
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options={}, content=[]):
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set_classes(options)
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return [self.node_class(rawtext, text, **options)], []
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class CustomRole(object):
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"""
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Wrapper for custom interpreted text roles.
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"""
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def __init__(self, role_name, base_role, options={}, content=[]):
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self.name = role_name
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self.base_role = base_role
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self.options = None
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if hasattr(base_role, 'options'):
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self.options = base_role.options
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self.content = None
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if hasattr(base_role, 'content'):
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self.content = base_role.content
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self.supplied_options = options
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self.supplied_content = content
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def __call__(self, role, rawtext, text, lineno, inliner,
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options={}, content=[]):
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opts = self.supplied_options.copy()
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opts.update(options)
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cont = list(self.supplied_content)
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if cont and content:
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cont += '\n'
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cont.extend(content)
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return self.base_role(role, rawtext, text, lineno, inliner,
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options=opts, content=cont)
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def generic_custom_role(role, rawtext, text, lineno, inliner,
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options={}, content=[]):
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""""""
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# Once nested inline markup is implemented, this and other methods should
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# recursively call inliner.nested_parse().
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set_classes(options)
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return [nodes.inline(rawtext, text, **options)], []
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generic_custom_role.options = {'class': directives.class_option}
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######################################################################
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# Define and register the standard roles:
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######################################################################
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register_generic_role('abbreviation', nodes.abbreviation)
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register_generic_role('acronym', nodes.acronym)
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register_generic_role('emphasis', nodes.emphasis)
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register_generic_role('literal', nodes.literal)
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register_generic_role('strong', nodes.strong)
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register_generic_role('subscript', nodes.subscript)
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register_generic_role('superscript', nodes.superscript)
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register_generic_role('title-reference', nodes.title_reference)
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def pep_reference_role(role, rawtext, text, lineno, inliner,
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options={}, content=[]):
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try:
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pepnum = int(utils.unescape(text))
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if pepnum < 0 or pepnum > 9999:
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raise ValueError
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except ValueError:
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msg = inliner.reporter.error(
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'PEP number must be a number from 0 to 9999; "%s" is invalid.'
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% text, line=lineno)
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prb = inliner.problematic(rawtext, rawtext, msg)
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return [prb], [msg]
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# Base URL mainly used by inliner.pep_reference; so this is correct:
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ref = (inliner.document.settings.pep_base_url
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+ inliner.document.settings.pep_file_url_template % pepnum)
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set_classes(options)
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return [nodes.reference(rawtext, 'PEP ' + text, refuri=ref,
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**options)], []
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register_canonical_role('pep-reference', pep_reference_role)
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def rfc_reference_role(role, rawtext, text, lineno, inliner,
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options={}, content=[]):
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try:
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if "#" in text:
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rfcnum, section = utils.unescape(text).split("#", 1)
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else:
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rfcnum, section = utils.unescape(text), None
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rfcnum = int(rfcnum)
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if rfcnum < 1:
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raise ValueError
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except ValueError:
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msg = inliner.reporter.error(
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'RFC number must be a number greater than or equal to 1; '
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'"%s" is invalid.' % text, line=lineno)
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prb = inliner.problematic(rawtext, rawtext, msg)
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return [prb], [msg]
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# Base URL mainly used by inliner.rfc_reference, so this is correct:
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ref = inliner.document.settings.rfc_base_url + inliner.rfc_url % rfcnum
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if section is not None:
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ref += "#"+section
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set_classes(options)
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node = nodes.reference(rawtext, 'RFC ' + str(rfcnum), refuri=ref,
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**options)
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return [node], []
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register_canonical_role('rfc-reference', rfc_reference_role)
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def raw_role(role, rawtext, text, lineno, inliner, options={}, content=[]):
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if not inliner.document.settings.raw_enabled:
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msg = inliner.reporter.warning('raw (and derived) roles disabled')
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prb = inliner.problematic(rawtext, rawtext, msg)
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return [prb], [msg]
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if 'format' not in options:
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msg = inliner.reporter.error(
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'No format (Writer name) is associated with this role: "%s".\n'
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'The "raw" role cannot be used directly.\n'
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'Instead, use the "role" directive to create a new role with '
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'an associated format.' % role, line=lineno)
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prb = inliner.problematic(rawtext, rawtext, msg)
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return [prb], [msg]
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set_classes(options)
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node = nodes.raw(rawtext, utils.unescape(text, True), **options)
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node.source, node.line = inliner.reporter.get_source_and_line(lineno)
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return [node], []
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raw_role.options = {'format': directives.unchanged}
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register_canonical_role('raw', raw_role)
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def code_role(role, rawtext, text, lineno, inliner, options={}, content=[]):
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set_classes(options)
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language = options.get('language', '')
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classes = ['code']
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if 'classes' in options:
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classes.extend(options['classes'])
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if language and language not in classes:
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classes.append(language)
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try:
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tokens = Lexer(utils.unescape(text, True), language,
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inliner.document.settings.syntax_highlight)
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except LexerError as error:
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msg = inliner.reporter.warning(error)
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prb = inliner.problematic(rawtext, rawtext, msg)
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return [prb], [msg]
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node = nodes.literal(rawtext, '', classes=classes)
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# analyse content and add nodes for every token
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for classes, value in tokens:
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if classes:
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node += nodes.inline(value, value, classes=classes)
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else:
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# insert as Text to decrease the verbosity of the output
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node += nodes.Text(value, value)
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return [node], []
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code_role.options = {'class': directives.class_option,
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'language': directives.unchanged}
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register_canonical_role('code', code_role)
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def math_role(role, rawtext, text, lineno, inliner, options={}, content=[]):
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set_classes(options)
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i = rawtext.find('`')
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text = rawtext.split('`')[1]
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node = nodes.math(rawtext, text, **options)
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return [node], []
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register_canonical_role('math', math_role)
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######################################################################
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# Register roles that are currently unimplemented.
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######################################################################
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def unimplemented_role(role, rawtext, text, lineno, inliner, attributes={}):
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msg = inliner.reporter.error(
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'Interpreted text role "%s" not implemented.' % role, line=lineno)
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prb = inliner.problematic(rawtext, rawtext, msg)
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return [prb], [msg]
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register_canonical_role('index', unimplemented_role)
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register_canonical_role('named-reference', unimplemented_role)
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register_canonical_role('anonymous-reference', unimplemented_role)
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register_canonical_role('uri-reference', unimplemented_role)
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register_canonical_role('footnote-reference', unimplemented_role)
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register_canonical_role('citation-reference', unimplemented_role)
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register_canonical_role('substitution-reference', unimplemented_role)
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register_canonical_role('target', unimplemented_role)
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# This should remain unimplemented, for testing purposes:
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register_canonical_role('restructuredtext-unimplemented-role',
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unimplemented_role)
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def set_classes(options):
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"""
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Auxiliary function to set options['classes'] and delete
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options['class'].
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"""
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if 'class' in options:
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assert 'classes' not in options
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options['classes'] = options['class']
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del options['class']
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