Re: links-9.0 v3

[Nicolas Goaziou <mail@nicolasgoaziou.fr>]

Hello,

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

> I don't understand what you mean here. The contents of org-link
> protocols (in master) looks a lot like a list of (link-type :follow
> :export), e.g.

You're right. Keys in `org-link-protocols' are types.

>>   (nth 1 (assoc app org-link-protocols))
>
> I see that these are not the same, since type != app.

Per the above, this snippet from `org-open-at-point' is suspicious.

> I was referring to the optional parameter, although I reconsider it
> here.  I don't understand how does the "application" get to the
> follow functions of links other than file+sys and file+emacs. It seems
> like we would need to allow type+application:path as a link syntax and
> extend the link-parser to get the application. Right now it looks like
> the parser only adds application properties to file type links.

file+sys and file+emacs predate the parser. Since the manual doesn't
seem to generalize them, parser support for them is rather minimalist.

I really hope this syntax is not going to be extended, because it
doesn't sound right to define the application opening a link at the
syntax level.

> I don't mind this (it makes links more flexible after all ;) OTOH, we
> would have to "register" each type+application for the link regexp, and
> then each type can have its own follow function, so it seems unnecessary
> to me.

I agree. As long as we need the regexp (because of plain links,
actually), my suggestion is a false good idea.

> My understanding of your statement of the problem is that the
> link-parser recognizes file:path, file+sys:path, and file+emacs:path as
> links of type "file", with different "application" properties. In the
> implementation of org-open-at-point on master, there is a cond branch
> for the "file" type link, and inside that the application is checked.
> Hence, without your suggestion at the end, there is not a way to access
> the :follow function of file+sys or file+emacs.
>
> To me this seems to be an unnecessary distinction from a link point of
> view since those three file links could just be defined as regular links
> with different follow/export functions. OTOH, perhaps there are other
> places in org-mode that rely on being able to tell when a link is a
> file, even if they are labeled file+sys or file+emacs that I am not
> aware of?

Any use not relying on :follow does not care above "+sys" or "+emacs".
E.g., during export, file+sys and file+emacs are treated the same.

> If I compare this to what exists in org-ref, for example, there
> are close to 40 different types of citations one can use, but they are
> all fundamentally "cite" types. They all share a common follow action,
> but have different export functions. When defined as separate links, I
> use them like cite:key citenum:key, citet:key, autocite:key, etc...
>
> Even here while I can see some utility for an application, e.g. perhaps
> to open the key in zotero, or mendeley or bibtex, I would normally
> associate that action with the :follow function. Am I missing
> something?

I think file+app was designed to override :follow function, so
associating the action with the :follow function wouldn't help.

> I only mentioned it because it seems to be in there in master via this line:
>
> (regexp-opt (cons "coderef" org-link-types)
>
> but it looks like it is in there in a different sort of way. It doesn't
> seem important here.

The line above creates a regexp matching types, as stored by the parser,
as returned by (org-element-property :type link). This can be "coderef".

OTOH (regexp-opt org-link-types) is meant to match links in an Org
buffer, where there is no "coderef".

Regards,

-- 
Nicolas Goaziou