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Mailing list for the LaTeX3 project <[log in to unmask]>
Frank Mittelbach <[log in to unmask]>
Sat, 21 Jun 1997 00:12:22 +0200
Mailing list for the LaTeX3 project <[log in to unmask]>
text/plain (61 lines)

another one of those discussions getting carried out under a strange
subject  (do think about all those poor historians one day)

 > Ok, I agree that there are some `standard' LaTeX commands, which are
 > `recommended for use'. But since the only 100% correct interpreter
 > of LaTeX files is TeX, then, in principle, all TeX commands
 > are valid (and they are also LaTeX commands by definition---since LaTeX
 > is able to parse them).

i think that is saddling the horse from the tail. if you look at the
way Lamport originally wrote LaTeX you will find that he used a pascal
like peudo code and later on translated it into TeX (and sometimes got
the TeX interpeter changed or enhanced because he asked Don something
that wasn't possible.

so execpt for the moment that there is an abstract LaTeX language and
it is defined by the LaTeX manual. and even if one of its interpreter
(TeX) allows to use constructs outside of it this doesn't mean that
they are part of the language, it only means that such documents are
not latex documents (only that we don't mind much as long as we all
use the same interpreter.

but your point that there is only one such interpreter is simply
wrong. there is, for example, a voice rendering system that turns
latex including math and all into speech --- very impressive in fact,
and it deals with the full latex language as defined above.

 > Yes, the use of some TeX constructs can seriously
 > hamper parsing of LaTeX source files by `third party' parsers,
 > and because of that one should use `undocumented' LaTeX commands
 > only inspecial cases.

wrong. because of that they are not LaTeX commands and the results are
not latex documents, this is like html with browser extension, or C
with compiler directives or ... you might get it through some other
interpreter but you leave the language proper if you use them.

 > >  > > TeX has a syntax? New concept.... :-)
 > >  >
 > >  > Of course, it has. :-) If not, than how can one get LaTeX to have syntax?
 > >
 > > By the very same argument, the ASCII code table has syntax, since you
 > > can build Pascal, C, C++,... out of it. That's a red herring.
 > I can't agree with this. :-)

i think you understood what Rainer was driving at. okay, you can say
that vanilla TeX (ie initex) already has syntax but it is on a
different level as the LaTeX syntax. and that's the important point as
it allows to produce parser which validate or use documents written in
latex without being at all able to handle arbitrary TeX input,
while on the other hand for something like plain TeX you really need a
parser which is at least powerful as TeX (could be e-TeX :-) to parse
an arbitrary document in that language

good night