Re: [O] org-player and switch to lexical binding in org.el

[Michael Brand]

Hi Nicolas

On Fri, Jan 29, 2016 at 2:32 PM, Nicolas Goaziou <address@hidden> wrote:
> My suggestion was hypothetical, and not yet implemented. No wonder it
> doesn't work.
>
> If you think this change sounds reasonable, I can implement it, tho.
> However, there is some backward incompatibility involved.
>
> The current solution, i.e., using `eval' only provides `file' symbol.

Only slowly I begin to get it partially. My observation is that if the
current `org-open-file' would be changed to

    (eval cmd
          ;; LEXICAL argument.
          `((file . ,(convert-standard-filename file))
            (link . ,dlink)))

to provide also the `link' symbol then a

    (add-to-list 'org-file-apps
                 (cons (concat org-player-file-extensions-regexp
                               "::\\([0-9]+:[0-9]+\\(:[0-9]+\\)?\\)")
                       '(org-player-play-file file (match-string 1 link))))

which is simple enough for me to understand in org-player.el works.
This situation looks favorable to me at least for a first step because
it would mean a version of org-player.el that remains compatible with
"any" Org before lexical binding in org.el
(release_8.3.3-426-g1f49e9f) but would also become compatible again
starting with one of the next commits in Org master.

Do I understand correct that this would not break any backward
compatibility with all other existing and correct use of
`org-file-apps'?

On Sun, Jan 17, 2016 at 9:40 PM, Nicolas Goaziou <address@hidden> wrote:
> I don't like the current solution either (eval with a LEXICAL argument).
>
> I think it would be better to use un function with two arguments (file
> and link-string instead). This is not backward compatible, but the
> change is trivial: sexp -> (lambda (file link) sexp).

I am concerned about backward compatibility and don't understand the
lambda part enough: Would backward compatibility be broken only for
org-player.el or also for other existing and correct use of
`org-file-apps'?

Or can `org-open-file' support both for some time like this?:

    (if (eq (car cmd) 'lambda)
        ;; Function.
        (funcall cmd (convert-standard-filename file) dlink)
      ;; Sexp, deprecated.
      (eval cmd `((file . ,(convert-standard-filename file))
                  (link . ,dlink))))

Michael