On Sat, Jul 29, 2023 at 05:33:18PM +0100, David Carlisle wrote:
> On 29/07/2023 12:21, LARONDE Thierry wrote:
> > But this is exactly my question: is it enough for LaTeX?
> 
> For latex, the only requirement is that all the file primitives use the
> same search  so \xxx{foooo}
> 
> refers to the same file if \xxx is \input or \(pdf}filesize or whatever.
> {note luatex and web2c engines accept \input{...} with braces at the
> primitive level.)
> 
> latex also assumes it can use double quotes to guard spaces \input "a b
> c .tex" and can use utf-8 filenames {although it won't generate
> 
> such file names unless the input files already use them,}

Then this is fine because this has been added too as an "input.ch" that
one can find with the Prote things (accessible from:

https://kertex.kergis.com/en/prote.html

) and the input stuff is documented here (once more, I made this with
the help of Phelype Oleinik who provided me with examples of input and
expected output):

https://downloads.kergis.com/kertex/input.pdf

> 
> Historically latex could not be proscriptive here as it ran on operating
> systems with no extension (sty, cls were implemented as a folder
> 
> cls/article)

So this is as I interpreted the "system dependencies": one could enter
"foo/bar/this.that" and this was the glue code that made it work on the
system (foo could be a database; bar a table; this a record with some
field "this" and "that" the corresponding field of the record to input).

But for me, a user could type things exactly the same way on whatever
system leading to the same result.

>  on flat file systems with no directories, and other
> variants. For many years though now, web2c based systems have dominated and
> 
> mostly file handling has normalised on the "/" path separator, "."
> extension and spaces allowed via " quoting. (kpathsea has no way to
> input a file with a " in its name)

Yes. This is what I have seen and have made things "bug" compatible in
this area with the "input.ch".

> 
> 
> So if the handling of search paths or extensionless files differs in
> your implementation, that will not affect latex as a system but may
> affect some edge case packages
> 
> or documents inputting Makefile or whatever, but that has always been a
> possibility that filenames on one system are illegal on another.

No it seems to be fine.

I'm not a LaTeX user (but the majority of users are LaTeX ones, so I
have to make LaTeX available) but I have to say the way the LaTeX
team has made things quite orthogonal to the rest is, in my never
humble opinion, quite good (the way even that the
proceeding---unpacking---uses TeX instead of relying on varying system
utilities is a major step towards "universal" TeX packages).

Keep things like this! And now, LaTeX is safe because even if all the
engines "du jour" would disappear (because of some patent problem;
code/lib compatibility; compiler dependency: C++ etc.), there is a
prote.ch and an input.ch that allow you to have a LaTeX compliant
engine that can be built on whatever system:

	TeX + e-TeX + Prote + input -> OK for LaTeX.

And there is no strings attached to prote.ch and input.ch. So even if I
disappear---whether dropping any work on this area or simply, as
anybody, because I will die---the show can go on.

Best,
-- 
        Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
                     http://www.kergis.com/
                    http://kertex.kergis.com/
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