Re: [Texmacs-dev] (For the Wikipedia article) Algorithms and format

[Giovanni Piredda]

On 30.11.20 16:03, TeXmacs wrote:
> Hi Giovanni,
>
> On Mon, Nov 30, 2020 at 01:56:13PM +0100, Giovanni Piredda wrote:
> > > However you need also to add that the \extern primitive allows to
> > > access these computational capabilities with an underlying
> > > scripting language. Here the comparison can be made with HTML/JS.
> > And the native macro system too pushes one outside the markup system, right?
> One has to distinguish between the 'syntax' of a document
> (the way a parser should understand it) and its actual 'semantics'.
> The _syntax_ of TeXmacs documents is relatively simple:
> anyone can write a parser for TeXmacs documents.
> The semantics of TeXmacs is more complex,
> since you may need to evaluate macros or extern constructs.
> The same holds for Html+Javascript.
>
> In the case of TeX/LaTeX, there is no clean distinction between
> syntax and semantics, whence the problems for parsing and converting LaTeX.
Thanks for the answer, it will take a while to grasp this (and the 
discussion with Massimiliano) well enough that I can write about it on 
Wikipedia. The whole "conversion" issue must be more subtle than I 
perceive because (despite several explanations) I do not yet understand 
why in general it does not work. One objection to "the halting problem 
forbids conversion" that is in my mind is that it should not be possible 
to write compilers. But we can drop the topic for the moment, I will go 
back to this if I feel I have made some progress.

Besides, on Wikipedia - for the other languages, I will do what I can 
(i.e. "value substitutions") but will not use Google translate, although 
I know that it works well, as I want to be confident of the things that 
I write.


> > Finally, for my remark that TeX is the easiest to read "markup" that
> > I know, it occurred to me that the format of computer algebra
> > systems is still easier to read; but perhaps it is not comprehensive
> > enough to be used for typesetting a document, and if you include
> > more syntactic expressions so that it is, it becomes as difficult to
> > read as TeX at least. Maybe I will experiment a bit with
> > Mathematica, which as far as I remember can format mathematical
> > expressions as well; I need to express all input in linear form of
> > course otherwise it is easier to read but the comparison is unfair ;-)
> This is getting more and more off-topic.
You are right---it is something that interests me, but this is not the 
right place to discuss it.

G.