Thread-Topic: template vs template-alt
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Date:         Thu, 27 Aug 2009 10:43:09 +0100
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From: "J.Fine" <J.Fine@OPEN.AC.UK>
Subject: Re: template vs template-alt
To: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
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Status: R

Will Robertson wrote:

> On 26/08/2009, at 8:39 PM, Lars Hellström wrote:
>
> > One remark without having looked at template-alt in detail is
> > however that the signatures above feel as though they're on the
> > wrong side of the =. That there are two arguments is a property of
> > number-format; you need to know this when providing a value for this
> > parameter. The :N signature rather seems like it applies to the
> > implementation, the details of which are otherwise in the right hand
> > side.
>
>
> The current interface evolved from pgfkeys; I can't say I disagree
> with you but I think a simpler scheme might involve a more complex
> parser.
>
> This is what the current syntax is:
>
>        number-format .set:N = \caption_number_format:nn
>
> The problem in parsing is that spaces are (probably) going to be
> ignored, so there has to be some token between the key, the signature,
> and the argument. We could read everything up to the first brace, I
> suppose:
>
>        number-format = set:N {\caption_number_format:nn}

[snip]

This illustrates the point I made before (named parameters for macros), which is that the implementation language (TeX macros) is constraining what the system can do (the input syntax).

Donald Knuth wanted TeX to be 'just a typesetting language' and said that 'if there were a universal simple interpretive language that was common to other systems, naturally I would have latched onto that right away'.

Please, please, please decide what you want to do and then decide the implementation language.  (Leslie Lamport did something similar with LaTeX, when he wrote much of the code in Lisp before translating it into TeX macros.  This is visible in the comments that were part of LaTeX209 source.)

Please don't decide ahead of time to write the whole system in TeX macros.

--
Jonathan


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