# $Id: misc.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.
"""
Miscellaneous transforms.
"""
__docformat__ = 'reStructuredText'
from docutils import nodes
from docutils.transforms import Transform
class CallBack(Transform):
"""
Inserts a callback into a document. The callback is called when the
transform is applied, which is determined by its priority.
For use with `nodes.pending` elements. Requires a ``details['callback']``
entry, a bound method or function which takes one parameter: the pending
node. Other data can be stored in the ``details`` attribute or in the
object hosting the callback method.
"""
default_priority = 990
def apply(self):
pending = self.startnode
pending.details['callback'](pending)
pending.parent.remove(pending)
class ClassAttribute(Transform):
"""
Move the "class" attribute specified in the "pending" node into the
immediately following non-comment element.
"""
default_priority = 210
def apply(self):
pending = self.startnode
parent = pending.parent
child = pending
while parent:
# Check for appropriate following siblings:
for index in range(parent.index(child) + 1, len(parent)):
element = parent[index]
if (isinstance(element, nodes.Invisible)
or isinstance(element, nodes.system_message)):
continue
element['classes'] += pending.details['class']
pending.parent.remove(pending)
return
else:
# At end of section or container; apply to sibling
child = parent
parent = parent.parent
error = self.document.reporter.error(
'No suitable element following "%s" directive'
% pending.details['directive'],
nodes.literal_block(pending.rawsource, pending.rawsource),
line=pending.line)
pending.replace_self(error)
class Transitions(Transform):
"""
Move transitions at the end of sections up the tree. Complain
on transitions after a title, at the beginning or end of the
document, and after another transition.
For example, transform this::
<section>
...
<transition>
<section>
...
into this::
<section>
...
<transition>
<section>
...
"""
default_priority = 830
def apply(self):
for node in self.document.findall(nodes.transition):
self.visit_transition(node)
def visit_transition(self, node):
index = node.parent.index(node)
error = None
if (index == 0
or isinstance(node.parent[0], nodes.title)
and (index == 1
or isinstance(node.parent[1], nodes.subtitle)
and index == 2)):
assert (isinstance(node.parent, nodes.document)
or isinstance(node.parent, nodes.section))
error = self.document.reporter.error(
'Document or section may not begin with a transition.',
source=node.source, line=node.line)
elif isinstance(node.parent[index - 1], nodes.transition):
error = self.document.reporter.error(
'At least one body element must separate transitions; '
'adjacent transitions are not allowed.',
source=node.source, line=node.line)
if error:
# Insert before node and update index.
node.parent.insert(index, error)
index += 1
assert index < len(node.parent)
if index != len(node.parent) - 1:
# No need to move the node.
return
# Node behind which the transition is to be moved.
sibling = node
# While sibling is the last node of its parent.
while index == len(sibling.parent) - 1:
sibling = sibling.parent
# If sibling is the whole document (i.e. it has no parent).
if sibling.parent is None:
# Transition at the end of document. Do not move the
# transition up, and place an error behind.
error = self.document.reporter.error(
'Document may not end with a transition.',
line=node.line)
node.parent.insert(node.parent.index(node) + 1, error)
return
index = sibling.parent.index(sibling)
# Remove the original transition node.
node.parent.remove(node)
# Insert the transition after the sibling.
sibling.parent.insert(index + 1, node)