Re: [PATCH] Add support for $…$ latex fragments followed by a dash

[Tim Cross <theophilusx@gmail.com>]

Ihor Radchenko <yantar92@gmail.com> writes:

> Rudolf Adamkovič <salutis@me.com> writes:
>
>> Let $r_i$ denote the \(i\)-th rotation of $t$ with a suffix of $\ell|t|$
>> characters deleted, for […]
>>
>> Me, if I could, I would pay money for this feature, for it would allow
>> me to use $$ consistently, focusing on mathematics instead of markup
>> idiosyncrasies of "rotation $i$" versus "\(i\)-th rotation".
>
> Would it improve things for you if we change how \(...\) _looks_ in Org
> buffers?
>
> The problem with parsing is more than just supporting $i$-th and
> similar. For example, AMS style guide explicitly advises against using
> $i$-th in favour of $i$th [1]:
>
>     Do not hyphenate “th” expressions: xth, not x-th or xth .
>
> We can theoretically make a change to support "-", but then it will be
> logical to support $i$th as well. (If we don't some users will still be
> confused after trying to write $i$th and then not getting the expected
> results). In this question, it would make sense to implement
> all-or-everything approach. Otherwise, confusion (like raised in this
> thread) will be inevitable.
>
> However, from point of view of Org mode parser, supporting $i$th is a
> nightmare.  Remember that Org mode is _not_ LaTeX and we have to support
> a lot more frivolous syntax (even in LaTeX, runaway $ is often a source
> of cryptic compilation errors). Currently, we _must_ rely on heuristics
> to determine $$-style latex fragments. I do not know any way to support
> $$ syntax without creating deviations from LaTeX. Extending the
> heuristics will not resolve the underlying ambiguity of $$ syntax, just
> hide it within even more obscure cases.
>
> Given the raised concerns, may we solve the issue with too verbose
> \(...\) unambiguous syntax using the following approach:
> 1. Fontify \(...\) replacing the brackets with a single character. For
>    example:
>
>       \(...\) -> ⁅...⁆
>
> 2. Provide convenient way to input \(\) brackets through
>    electric-pair-mode or trough org-cdlatex-mode.
>
> Best,
> Ihor
>
> [1] https://www.ams.org/publications/authors/AMS-StyleGuide-online.pdf

+1.

Just my $0.02 worth -

I think this is the right approach. Retaining support for $..$ doesn't
seem feasible given all the complexities it brings with it. The main
objections to the alternative appear to centre around readability and
inconvenience of having to type additional characters or dealing with
muscle memory use to $...$. These are essentially interface issues and I
think we can largely address them using existing Emacs facilities. This
will reduce the change impact to that sub-set of org users accustomed to
$...$ while bringing the benefit of a cleaner and potentially more
efficient parser to all org users.

If we do deprecate support for $...$, it might also be a good idea to
see if we can add a utility function which would make it easier for
people to migrate existing documents to the new/alternative syntax. For
the same reason it is hard to reliably parse $...$ syntax, we probably
can't automate that transition, but we should be able to reduce the effort
required to update existing documents.