Re: more m4 underquotations

[Bruno Haible]

Bruce Korb wrote (in a discussion about how to avoid m4 underquotation bugs):
> The complexity stems from both the m4 language choice and
> the brevity of the chosen quote markers.  The language issue
> is that macros inherit the quote markers from their invocation
> environment.  Nothing you can do about that.  (Too late to
> choose another language without starting over.)

Yes. And all the ASCII pairs (), {}, [], <> are already used in the shell
language, which is what autoconf macros expand into.

> A better choice on the quote phrase is a possibility, but it
> would be a pita to implement.  Still, it would be useful to
> bite the bullet and do it.  Two character sequences for open
> and close would massively improve the ambiguity, and likely
> remove much of the need for those quadrigraphs.

Yes. Now that Unicode capable text editors are everywhere (including Emacs 22),
one can consider to go beyond ASCII. This means, choose non-ASCII Unicode
characters as opening and closing quote:

  changequote(«,»)

More choices are possible, see [1]. Use this consistently for autoconf
macros, and they will never be confused with the (), {}, [], <> that are
used for shell programming.

Bruno


[1] http://www.daube.ch/docu/glossary/quotation_marks.html