Should we obsolete org-emphasis-alist? (was: [PATCH v5] org.el: Warning for unsupported markers in `org-set-emphasis-alist')

[Ihor Radchenko <yantar92@posteo.net>]

Max Nikulin <manikulin@gmail.com> writes:

>> +(add-variable-watcher 'org-emphasis-alist #'org-emphasis-alist--check-value)
>
> Thinking more I have realized that I am in doubts if 
> `add-variable-watcher' is appropriate tool in this particular case. The 
> only way to get some effect from change of `org-emphasis-alist' is to 
> call `org-set-emph-re' (its :set function), so it should be enough to 
> call `org-emphasis-alist--check-value' from `org-set-emph-re'.

Upon looking closer, `org-set-emph-re' is not affected by the value of
`org-emphasis-alist' with a single exception when the value is nil.

> I have no idea what should be considered as best practice: should 
> `set-default-toplevel-value' be combined with changes of `org-emph-re' 
> as it is done in current code or `org-set-emph-re' should be split into 
> the function that modifies `org-emph-re' (so it can be called 
> separately) and a tiny setter (that may be defined as lambda this case) 
> that calls the new function and `set-default-toplevel-value'.

I now reviewed the usage of `org-emphasis-alist' and setting/changing
the value has the following effects:

1. nil (and only nil) value makes `org-emph-re' and `org-verbatim-re'
   nil. Otherwise, these regexps are not affected.

   Also, `org-emph-re' only affects fontification.
   `org-verbarim-re' affects fontification and
   `org-in-verbatim-emphasis'. The latter should be fixed to use
   org-element API.

2. The value affects `org-mode-transpose-word-syntax-table'. Should be
   fixed - parser is not affected by `org-emphasis-alist'.

3. Fontification is affected in `org-do-emphasis-faces'.

4. Emphasis selection dialogue in `org-emphasize' is only using the
   emphasis from the alist.

That's all.

I think that we should simply obsolete `org-emphasis-alist' and
introduce individual faces for emphasis.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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