Re: [patch] ox-latex.el: fix blank lines behavior in verse block

[Juan Manuel Macías]

Ihor Radchenko writes:

> Juan Manuel Macías <maciaschain@posteo.net> writes:

>> +         (vwidth (if (not lit)
>> +                 (if versewidth (format "\\settowidth{\\versewidth}{%s}\n" 
>> versewidth) "")
>> +               ""))
>
> Can just do (if (and versewidth (not lit)) (format ...) "")
>
>> +         (linreset (if (not lit)
>> +                   (if lin "\n\\poemlines{0}" "")
>> +                 "")))
>
> (if (and lin (not lit)) ...)

Thanks for the suggestions. Yes, it's simpler that way.

>>      (concat
>>       (org-latex--wrap-label
>>        verse-block
>>        ;; In a verse environment, add a line break to each newline
>>        ;; character and change each white space at beginning of a line
>> -      ;; into a space of 1 em.  Also change each blank line with
>> -      ;; a vertical space of 1 em.
>> -      (format "%s\\begin{verse}%s\n%s\\end{verse}%s"
>> +      ;; into a normal space, calculated with `\fontdimen2\font'.
>> +      ;; One or more blank lines between lines are exported as a
>> +      ;; single blank line.  If the `:literal' attribute is used,
>> +      ;; CONTENTS is exported as is, with no environment, preserving
>> +      ;; line breaks and vertical and horizontal spaces.
>> +      (format (if (not lit)
>> +              "%s\\begin{verse}%s\n%s\\end{verse}%s"
>> +            "%s%s\n%s%s")
>
> In the case of lit vwidth and attr are always empty. So, you are
> inserting an extra newline in front. Is it intentional?

I used that procedure because an extra blank line before (in the LaTeX
code) it has no effect in LaTeX compilation. And in case the :literal
attribute is present, vertical spaces are achieved by explicit
\vspace*{}. One or more empty lines before it just marks the beginning
of a new paragraph.

Naturally, if :literal is used the rest of attributes are meaningless
because they are intended for the verse environment. They can even give
some error in the compilation. So I opted to disable them with the mere
presence of :literal, leaving them 'empty' (so as not to manipulate the
function further).

>> +                (concat "\\("
>> +                        (regexp-quote org-latex-line-break-safe)
>> +                        "\n\\)"
>> +                        "\\(^[ \t]*"
>> +                        (regexp-quote org-latex-line-break-safe)
>> +                        "\n"
>> +                        "\\)+")
>> +              (concat "^[ \t]*" (regexp-quote org-latex-line-break-safe) 
>> "$"))
>
> May also use rx for better readability.

I remember that I tried rx a while ago and found it very useful and
comfortable, but then I haven't done anything with it. The fact is that
over time I have ended up getting used to suffering from the classic
regexp and it is hard for me to get out of there :-). Of course, with rx
it would be clearer but I would have to refresh my memory.

-- 
Juan Manuel Macías

https://juanmanuelmacias.com

https://lunotipia.juanmanuelmacias.com

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