python-peps/docutils/parsers/rst/directives/__init__.py

236 lines
8.2 KiB
Python

# Author: David Goodger
# Contact: goodger@users.sourceforge.net
# Revision: $Revision$
# Date: $Date$
# Copyright: This module has been placed in the public domain.
"""
This package contains directive implementation modules.
The interface for directive functions is as follows::
def directive_fn(name, arguments, options, content, lineno,
content_offset, block_text, state, state_machine):
code...
# Set function attributes:
directive_fn.arguments = ...
directive_fn.options = ...
direcitve_fn.content = ...
Parameters:
- ``name`` is the directive type or name.
- ``arguments`` is a list of positional arguments.
- ``options`` is a dictionary mapping option names to values.
- ``content`` is a list of strings, the directive content.
- ``lineno`` is the line number of the first line of the directive.
- ``content_offset`` is the line offset of the first line of the content from
the beginning of the current input. Used when initiating a nested parse.
- ``block_text`` is a string containing the entire directive. Include it as
the content of a literal block in a system message if there is a problem.
- ``state`` is the state which called the directive function.
- ``state_machine`` is the state machine which controls the state which called
the directive function.
Function attributes, interpreted by the directive parser (which calls the
directive function):
- ``arguments``: A 3-tuple specifying the expected positional arguments, or
``None`` if the directive has no arguments. The 3 items in the tuple are
``(required, optional, whitespace OK in last argument)``:
1. The number of required arguments.
2. The number of optional arguments.
3. A boolean, indicating if the final argument may contain whitespace.
Arguments are normally single whitespace-separated words. The final
argument may contain whitespace if the third item in the argument spec tuple
is 1/True. If the form of the arguments is more complex, specify only one
argument (either required or optional) and indicate that final whitespace is
OK; the client code must do any context-sensitive parsing.
- ``options``: A dictionary, mapping known option names to conversion
functions such as `int` or `float`. ``None`` or an empty dict implies no
options to parse.
- ``content``: A boolean; true if content is allowed. Client code must handle
the case where content is required but not supplied (an empty content list
will be supplied).
Directive functions return a list of nodes which will be inserted into the
document tree at the point where the directive was encountered (can be an
empty list).
See `Creating reStructuredText Directives`_ for more information.
.. _Creating reStructuredText Directives:
http://docutils.sourceforge.net/spec/howto/rst-directives.html
"""
__docformat__ = 'reStructuredText'
from docutils import nodes
from docutils.parsers.rst.languages import en as _fallback_language_module
_directive_registry = {
'attention': ('admonitions', 'attention'),
'caution': ('admonitions', 'caution'),
'danger': ('admonitions', 'danger'),
'error': ('admonitions', 'error'),
'important': ('admonitions', 'important'),
'note': ('admonitions', 'note'),
'tip': ('admonitions', 'tip'),
'hint': ('admonitions', 'hint'),
'warning': ('admonitions', 'warning'),
'topic': ('body', 'topic'),
'line-block': ('body', 'line_block'),
'parsed-literal': ('body', 'parsed_literal'),
#'questions': ('body', 'question_list'),
'image': ('images', 'image'),
'figure': ('images', 'figure'),
'contents': ('parts', 'contents'),
'sectnum': ('parts', 'sectnum'),
#'footnotes': ('parts', 'footnotes'),
#'citations': ('parts', 'citations'),
'target-notes': ('references', 'target_notes'),
'meta': ('html', 'meta'),
#'imagemap': ('html', 'imagemap'),
'raw': ('misc', 'raw'),
'include': ('misc', 'include'),
'replace': ('misc', 'replace'),
'restructuredtext-test-directive': ('misc', 'directive_test_function'),}
"""Mapping of directive name to (module name, function name). The directive
name is canonical & must be lowercase. Language-dependent names are defined
in the ``language`` subpackage."""
_modules = {}
"""Cache of imported directive modules."""
_directives = {}
"""Cache of imported directive functions."""
def directive(directive_name, language_module, document):
"""
Locate and return a directive function from its language-dependent name.
If not found in the current language, check English. Return None if the
named directive cannot be found.
"""
normname = directive_name.lower()
messages = []
msg_text = []
if _directives.has_key(normname):
return _directives[normname], messages
canonicalname = None
try:
canonicalname = language_module.directives[normname]
except AttributeError, error:
msg_text.append('Problem retrieving directive entry from language '
'module %r: %s.' % (language_module, error))
except KeyError:
msg_text.append('No directive entry for "%s" in module "%s".'
% (directive_name, language_module.__name__))
if not canonicalname:
try:
canonicalname = _fallback_language_module.directives[normname]
msg_text.append('Using English fallback for directive "%s".'
% directive_name)
except KeyError:
msg_text.append('Trying "%s" as canonical directive name.'
% directive_name)
# The canonical name should be an English name, but just in case:
canonicalname = normname
if msg_text:
message = document.reporter.info(
'\n'.join(msg_text), line=document.current_line)
messages.append(message)
try:
modulename, functionname = _directive_registry[canonicalname]
except KeyError:
return None, messages
if _modules.has_key(modulename):
module = _modules[modulename]
else:
try:
module = __import__(modulename, globals(), locals())
except ImportError:
return None, messages
try:
function = getattr(module, functionname)
_directives[normname] = function
except AttributeError:
return None, messages
return function, messages
def flag(argument):
"""
Check for a valid flag option (no argument) and return ``None``.
Raise ``ValueError`` if an argument is found.
"""
if argument and argument.strip():
raise ValueError('no argument is allowed; "%s" supplied' % argument)
else:
return None
def unchanged(argument):
"""
Return the argument, unchanged.
Raise ``ValueError`` if no argument is found.
"""
if argument is None:
raise ValueError('argument required but none supplied')
else:
return argument # unchanged!
def path(argument):
"""
Return the path argument unwrapped (with newlines removed).
Raise ``ValueError`` if no argument is found or if the path contains
internal whitespace.
"""
if argument is None:
raise ValueError('argument required but none supplied')
else:
path = ''.join([s.strip() for s in argument.splitlines()])
if path.find(' ') == -1:
return path
else:
raise ValueError('path contains whitespace')
def nonnegative_int(argument):
"""
Check for a nonnegative integer argument; raise ``ValueError`` if not.
"""
value = int(argument)
if value < 0:
raise ValueError('negative value; must be positive or zero')
return value
def format_values(values):
return '%s, or "%s"' % (', '.join(['"%s"' % s for s in values[:-1]]),
values[-1])
def choice(argument, values):
try:
value = argument.lower().strip()
except AttributeError:
raise ValueError('must supply an argument; choose from %s'
% format_values(values))
if value in values:
return value
else:
raise ValueError('"%s" unknown; choose from %s'
% (argument, format_values(values)))