Re: [Docutils-develop] Writing directives

[David G. <go...@us...>]

Aahz wrote:
> Here's some sample reST text::
> 
>     Overall, my primary source for determining what to include in
>     this book was the netnews group ``comp.lang.python``.  I've been
>     reading that group for several years, and the same questions
>     seem to show up over and over again.
> 
>     .. index::
>         comp.lang.python
>         Usenet
>         netnews
> 
> What am I doing wrong with this directive::
> 
>     from docutils import nodes
>     from docutils.parsers.rst import directives
> 
>     registry = directives._directive_registry
>     registry['index'] = ('OOdirectives', 'index_directive')

You must be importing this module explicitly somewhere, right?
Otherwise, how does the registration code run before the directive is
registered? ;->

>     class index_entry(nodes.General, nodes.Element): pass

This is the problem.  Replace "nodes.Element" with
"nodes.TextElement".  Their __init__ signatures are different.

>     def index_directive(name, arguments, options, content, lineno,
>             content_offset, block_text, state, state_machine):
>         text = '\n'.join(content)
>         text_nodes, messages = state.inline_text(text, lineno)
>         node = index_entry(text, '', *text_nodes)
                                   ^^
Right here, the code is sending a string ('') as a child node.

>         return [node] + messages
> 
>     index_directive.content = 1

I'm guessing that this is a "first draft" of the directive, yes?
You'll probably want to create an index_entry for each of the terms
listed in the directive, and insert them at the beginning of the
paragraph (therefore "index_entry" should be an inline element).  In
fact, the class declaration should probably be::

    class index_entry(nodes.Inline, nodes.TextElement): pass

> If I replace the code of index_directive() with "return []", I don't
> get an exception.

That's odd.  Are you sure you made no other changes?  This is where
the error originates:

>       File "OOdirectives.py", line 17, in index_directive
>         node = index_entry(text, '', *text_nodes)

-- 
David Goodger  <go...@us...>  Open-source projects:
  - Python Docutils: http://docutils.sourceforge.net/
    (includes reStructuredText: http://docutils.sf.net/rst.html)
  - The Go Tools Project: http://gotools.sourceforge.net/