# $Id: components.py 9037 2022-03-05 23:31:10Z milde $
# Author: David Goodger <goodger@python.org>
# Copyright: This module has been placed in the public domain.
"""
Docutils component-related transforms.
"""
from docutils.transforms import Transform
__docformat__ = 'reStructuredText'
class Filter(Transform):
"""
Include or exclude elements which depend on a specific Docutils component.
For use with `nodes.pending` elements. A "pending" element's dictionary
attribute ``details`` must contain the keys "component" and "format". The
value of ``details['component']`` must match the type name of the
component the elements depend on (e.g. "writer"). The value of
``details['format']`` is the name of a specific format or context of that
component (e.g. "html"). If the matching Docutils component supports that
format or context, the "pending" element is replaced by the contents of
``details['nodes']`` (a list of nodes); otherwise, the "pending" element
is removed.
For example, up to version 0.17, the reStructuredText "meta"
directive created a "pending" element containing a "meta" element
(in ``pending.details['nodes']``).
Only writers (``pending.details['component'] == 'writer'``)
supporting the "html", "latex", or "odf" formats
(``pending.details['format'] == 'html,latex,odf'``) included the
"meta" element; it was deleted from the output of all other writers.
This transform is no longer used by Docutils, it may be removed in future.
"""
# TODO: clean up or keep this for 3rd party (or possible future) use?
# (GM 2021-05-18)
default_priority = 780
def apply(self):
pending = self.startnode
component_type = pending.details['component'] # 'reader' or 'writer'
formats = (pending.details['format']).split(',')
component = self.document.transformer.components[component_type]
for format in formats:
if component.supports(format):
pending.replace_self(pending.details['nodes'])
break
else:
pending.parent.remove(pending)