Re: [Docutils-develop] Processing inline roles

[Edward L. <ed...@gr...>]

David Goodger wrote:
> Done; checked in to CVS.

Looks good.

One other question I had was where pep_url and rfc_url should live. 
Currently, they're still in Inliner, but that doesn't seem appropriate. 
  Some other options:

   - Put them in module-level variables in roles.py
   - Put them in attributes on the functions that use them.  (This is a
     little odd, but would work).
   - Implement pep_reference_role and rfc_reference_role as class
     instances that implement __call__.  Something like this:

#----------------------------------------------------------------------
class URIReferenceRole:
     """Abstract base class for specialized reference roles."""
     def __call__(self, role, rawtext, text, lineno, inliner):
         try:
             self.verify(text)
         except ValueError, e:
             msg = inliner.reporter.error(str(e), line=lineno)
             prb = inliner.problematic(text, text, msg)
             return [prb, msg]
         label = self.label(text)
         uri = self.uri(text)
         return [nodes.referencenode(rawtext, label, refuri=uri)], []

     def verify(self, text):
         """Raise a ValueError if `text` is invalid."""

     def label(self, text):
         """Return the reference label corresponding to `text`"""

     def uri(self, text):
         """Return the reference target corresponding to `text`"""

class PEPReferenceRole(ReferenceRole):
     def __init__(self, base_url):
         pep_url = base_url+'pep-%04d.html'

     def verify(self, text):
         if not re.match(r'\d{1,4}'):
             raise ValueError('PEP number must be a number from 0 '+
                              'to 9999; %r is invalid.' % text)

     def label(self, text):
         return 'PEP %s' % text

     def uri(self, text):
         return self.pep_url % text

pep_reference_role = PEPReferenceRole('http://www.python.org/peps/')
local_pep_reference_role = PEPReferenceRole('')
register_canonical_role('pep-reference', pep_reference_role)
#----------------------------------------------------------------------

Then a user could override the pep location with:

     register_canonical_role('pep-reference', local_pep_reference_role)

or:

     my_pep_reference_role = PEPReferenceRole('http://somewhere/else/')
     register_canonical_role('pep-reference', my_pep_reference_role)

-Edward