1 # $Id: components.py 4564 2006-05-21 20:44:42Z wiemann $

     2 # Author: David Goodger <goodger@python.org>

     3 # Copyright: This module has been placed in the public domain.

     4 

     5 """

     6 Docutils component-related transforms.

     7 """

     8 

     9 __docformat__ = 'reStructuredText'

    10 

    11 import sys

    12 import os

    13 import re

    14 import time

    15 from docutils import nodes, utils

    16 from docutils import ApplicationError, DataError

    17 from docutils.transforms import Transform, TransformError

    18 

    19 

    20 class Filter(Transform):

    21 

    22     """

    23     Include or exclude elements which depend on a specific Docutils component.

    24 

    25     For use with `nodes.pending` elements.  A "pending" element's dictionary

    26     attribute ``details`` must contain the keys "component" and "format".  The

    27     value of ``details['component']`` must match the type name of the

    28     component the elements depend on (e.g. "writer").  The value of

    29     ``details['format']`` is the name of a specific format or context of that

    30     component (e.g. "html").  If the matching Docutils component supports that

    31     format or context, the "pending" element is replaced by the contents of

    32     ``details['nodes']`` (a list of nodes); otherwise, the "pending" element

    33     is removed.

    34 

    35     For example, the reStructuredText "meta" directive creates a "pending"

    36     element containing a "meta" element (in ``pending.details['nodes']``).

    37     Only writers (``pending.details['component'] == 'writer'``) supporting the

    38     "html" format (``pending.details['format'] == 'html'``) will include the

    39     "meta" element; it will be deleted from the output of all other writers.

    40     """

    41 

    42     default_priority = 780

    43 

    44     def apply(self):

    45         pending = self.startnode

    46         component_type = pending.details['component'] # 'reader' or 'writer'

    47         format = pending.details['format']

    48         component = self.document.transformer.components[component_type]

    49         if component.supports(format):

    50             pending.replace_self(pending.details['nodes'])

    51         else:

    52             pending.parent.remove(pending)