LATEX-L Archives

Mailing list for the LaTeX3 project

LATEX-L@LISTSERV.UNI-HEIDELBERG.DE

Options: Use Forum View

Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Lars Hellström <[log in to unmask]>
Reply To:
Mailing list for the LaTeX3 project <[log in to unmask]>
Date:
Fri, 28 Aug 2015 19:30:16 +0200
Content-Type:
text/plain
Parts/Attachments:
text/plain (53 lines)
Joseph Wright skrev 2015-08-27 22.18:
> On 27/08/2015 19:09, Joseph Wright wrote:
>> On 27/08/2015 18:28, Lars Hellström wrote:
>>> Bruno Le Floch skrev 2015-08-27 12.34:
>>>> That's much harder.  Catcode changes are probably warranted in this
>>>> case, since teaching TeX to nest parentheses in this way is tough.
>>>
>>> I seem to recall that I did demonstrate how to do that -- have TeX match
>>> parentheses in an expression, using delimited arguments rather than
>>> catcode changes -- in a mail to this very list several years ago... Yes,
>>> it was on 2011-10-19 and the subject was "Re: Church booleans".
>>
>> We do the same in xparse :-)

Are you saying xparse handles _matching_ of _nested_ parentheses? Because 
that is what I meant that I demonstrated. Using delimited arguments to grab 
parentheses without considering how they match against each other is of 
course a triviality, but also not useful for the problem considered.

>>> PS: I maintain that that approach to evaluating infix boolean
>>> expressions is far superior to what is currently offered in LaTeX3, but
>>> Bruno just seems to *love* his&&, with all its shortcomings. ;-)
>>
>> Will remind myself: as has been noted there is an issue with clearing up
>> certain tokens with the current lazy evaluation method.

More fundamentally, I believe it only supports expandable tests. There is no 
need for a boolean evaluation logic to require tests to be expandable (and 
nor does the logic itself need to be non-expandable).

>> Joseph
>>
>
> BTW, thread you mean starts
>
>    http://article.gmane.org/gmane.comp.tex.latex.latex3/2719
>
> I think the one you mean is
>
>    http://article.gmane.org/gmane.comp.tex.latex.latex3/2754

Ah, that is correct.

> Joseph
>
> P.S. Boolean expressions are Morten's code, not Bruno's :-)

Oh? I seem to recall Bruno posted repeatedly on it this summer, giving the 
appearance that he was actively working on precisely that code. My bad, in 
that case.

Lars Hellström

ATOM RSS1 RSS2