Re: Parsing a language with optional spaces

[Akim Demaille]

Hi Christian,

> Le 14 juil. 2020 à 13:44, Christian Schoenebeck <schoenebeck@crudebyte.com> a 
> écrit :
> 
>> -Except for GLR parsers (@pxref{Compiler Requirements for GLR}), the C
>> -code that Bison generates requires only C89 or later.  However, Bison
>> -itself requires common C99 features such as declarations after
>> -statements.  Bison's @code{configure} script attempts to enable C99 (or
>> -later) support on compilers that default to pre-C99.  If your compiler
>> -lacks these C99 features entirely, GCC may well be a better choice; or
>> -you can try upgrading to your compiler's latest version.
>> +Except for GLR parsers (which require C99), the C code that Bison generates
>> +requires only C89 or later.  However, Bison itself requires common C99
>> +features such as declarations after statements.  Bison's @code{configure}
>> +script attempts to enable C99 (or later) support on compilers that default
>> +to pre-C99.  If your compiler lacks these C99 features entirely, GCC may
>> +well be a better choice; or you can try upgrading to your compiler's
>> latest +version.
> 
> That would already be far beyond my personal level of detail. :) I mean it is 
> absolutely correct, but you barely find a C compiler for that to be an issue 
> at all nowaways. Usually you would need to explicitly force a compiler to 
> strict ISO C89 for that to happen today.

I mean to specify what the requirements for yacc.c are.  It's binding us with
our users, and they can rely on this.  I'll be very happy to move forward
(say in Bison 4) but we still have occasional reports when we depart from this.
For instance https://github.com/akimd/bison/issues/37.