Re: [patch][ox-latex] context-aware subscript

[Rasmus <rasmus@gmx.us>]

Hi Nicolas,

Nicolas Goaziou <n.goaziou@gmail.com> writes:

> Thanks for the patch. Here are some comments about it.

Sorry about the late reply

> Rasmus <rasmus@gmx.us> writes:
>
>> Currently one can't write something like \beta_t and get a nice
>> result
>> in org when exporting to LaTeX (where nice result := $\beta_t$).
>> This
>> patch tries to fix it.
>
> Translating \beta_t into $\beta$$_\text{t}$ and \beta_bar into
> $\beta$$ \text{bar}$ is intended.

I know it's intended but I dislike it.  In earlier version of
ox-latex.el it didn't use the \text-macro.

> Unless you explicitly ask for math mode, Org defaults to text
> mode. The
> fact that it needs to go through math mode to insert some entities is
> not relevant. 

I disagree that it is irrelevant.  Even so, the spacing is wrong
cf. below.

> IOW, there's a difference between \beta_{$t$} and \beta_t.

No doubt.

> Also, merging consecutive subscript and superscript is fragile (and
> the
> code in `org-latex--script-size' could be improved in that area), as
> it
> also depends on user's filters. Here is a contrived example:
>
> Let's assume I have a filter which removes any subscript with the
> letter
> "a" in it. With the following code:
>
>   \beta_a
>
> Trying to merge both the entity and the subscript will return
>
>   $\beta
>
> which is wrong.

OK.  Perhaps it can be made less fragile.

>> As is evident from the pdf output
>>
>>   $\alpha$$\beta$$_{\text{t}}$ ≠ $\alpha$$\beta$$_{{t}}$ ≠
>> $\alpha\beta_{t}$
>>
>> There seems to be no difference between $\alpha$$\beta$ and
>> $\alpha\beta$ in the pdf, but the latter is more aesthetically
>> pleasing in the source.
>
> Beautifying LaTeX code is fine, unless it means adding yet another
> variable, and making some assumptions about user's configuration. If
> it ain't broken, don't fix it.

But it is broken, since even 

(*)    $\beta$$_{\text{t}}$

doesn't produce the correct output (spacing is wrong; compare to
$\beta_{\text{t}}$).  In LaTeX, (*) represents two "math elements",
although the intention was to get only one.

To sum up, my (implicit) claim and what I intended to fix with the
patch, was

  1. Fixing the bug that subscripts produce wrong output.
  2. Try to make the type of subscript configurable.  Previously,
     "math subscripts" were forced, now \text subscripts are forced.
     
Please let me know whether either 1. or 2. is up for discussion or
whether the current state is to be accepted.

–Rasmus

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