Re: patch for custom colored links in org-mode

[Nicolas Goaziou <mail@nicolasgoaziou.fr>]

John Kitchin <jkitchin@andrew.cmu.edu> writes:

> I agree, it doesn't make sense to use it for customization. OTOH, it
> also adds the link type to org-link-types, rebuilds the regexp and the
> org-link-protocols.

It is possible to rebuild regexps upon modifying a defcustom.

> Do you think we would eliminate `org-link-types' and
> `org-link-protocols' then? That would be fine with me.

They would contain duplicate data, so they can be removed.

> I think we might still want an org-add-link-type function though, if
> there are additional things that need to be done after adding to
> `org-link-type-parameters', e.g. updating regexps. It might even be
> feasible to keep backward compatibility for code that already uses
> this.

We already have `org-make-link-regexp'. We can make it call
`org-element-update-syntax' at its end, so as to become a replacement
for `org-add-link-type'.

Every customization of `org-link-parameters' would then call
`org-make-link-regexp'. Users setting the variable by hand, or libraries
defining new types, would be required to call it explicitly, though.

I'm not sure about `org-add-link-type'. It introduces yet another way to
configure link, but makes possible to eschew the `org-make-link-regexp'
call. In any case, it needs to be kept around for
backward-compatibility, but could also be marked as obsolete, pointing
to `org-link-parameters' instead.

WDYT?

> Presumably we would then eliminate the "org-%s-complete-link"
> functions?

Indeed.

I think it is possible to proceed in four steps.

1. First, we create the variable, with appropriate getter, setter and
   default values. At this point it is sufficient to
   support :follow, :export and :completion properties only.

2. Then we get all the code base to extract information about links
   through this variable instead of various existing ways, namely,
   `org-%s-complete-link', `org-link-protocols' and `org-link-types'.

3. Then we extend it with new properties, i.e., :display, :echo
   and :face.

4. Document the changes in the manual and ORG-NEWS file.

You have mostly worked out the third part of the process. Do you want to
take a stab at any of the other steps? Or do you prefer me to do some
parts?

Regards,