1. Bison should never support a language with a different basic syntax
than C/C++ since we don't want Bison to have to parse such a language in
actions.
2. Bison might one day support such a language but Bison should parse
actions for them horribly incorrectly. Thus, we'll refuse to have
%language now to ensure that no one tries to parse them correctly then.
Obviously it's not #2. If it's #1, what's the harm in supporting
%language now? That doesn't prevent us from opposing specific languages
later.
It's neither #1 nor #2. It's more like "People might one day want Bison
to support a language with a different basic syntax than C/C++, and this
might require massive changes to the parser, making it close to
unmaintainable. Thus, we'll refuse to have %language now to set a
precedent that Bison's operation must be as language-independent as
possible (as opposed to the m4 skeletons)."
I agree that this doesn't prevent us from opposing specific languages
later. Also, Java also sets a (IMHO good) precedent of how to make
changes to Bison for the sake of supporting more languages: no change to
the parser, limited modifications to make the m4 skeletons more generic,
but *no change* to the grammar parser.
Then again, if we're not willing to parse any other syntax, I
guess that means we won't be adding very many other languages.
Actually, I think we can parse a lot of languages with some limitations.
in their use. Perl definitely has problems because of hieroglyphics in
the name -- this might extend to PHP in the future if we support $foo.
Python has some because of the indentation.
OTOH, Lisp has different semantics for apostrophes but you can restrict
yourself to (quote a b c) instead of '(a b c). Likewise Ruby and PHP
interpolate variables within a quoted string, and in this case Bison may
parse "the first token is $1" incorrectly. But even with these
limitations, the parser could "just work" for a lot of languages.
(Note that I'm not endorsing in any way the creation of Bison skeletons
for these languages...) ;-)
Sorry to force you to play devil's advocate, but I feel like I'm missing
the point.
No problem, it can work well. I hope this is clearer now?
Paolo
