Re: [Caml-list] autoconf and caml

[Kenneth Oksanen <cessu@hutcs.cs.hut.fi>]

>> I'm writing a piece of software using O'Caml and GNU autoconf (among
>> others).  In C the results of running `./configure' are conveniently
>> accessed with `#include "config.h"'.  My current solution is to
>> preprocess also the O'Caml code, but this requires some clumsy hacks
>> in Makefiles etc.  Is there a better way?  If not, then I'ld suggest
>> some flag in O'Caml which would run the source files through cpp.
>
>The -pp flag to ocamlc and ocamlopt lets you do this easily:
>  ocamlc -pp /lib/cpp ...

True, and this had already been kindly pointed out by some other
camlers.  A few remarks though:

This flag is not documented on the corresponding man-pages.

The flag does not exist in ocamlyacc and ocamllex.

ocamllex produces code that is not cpp-safe.  It contains definitions
of the form
  Lexing.lex_base = 
   "\000\000\255\255\254\255\002\000\248\255\001\000\247\255\246\255\
    \250\255\252\255\245\255\251\255\249\255\077\000\244\255\003\000\
etc.  At least when passed through GNU CPP version 2.96 20000731 (Red
Hat Linux 7.3 2.96-110) these become converted to
  Lexing.lex_base =
   "\000\000\255\255\254\255\002\000\248\255\001\000\247\255\246\255    \250\255\252\255\245\255\251\255\249\255\077\000\244\255\003\000    \030\000\031\000\160\000\235\000\054\001\129\001\204\001\023\002    \098\002\011\000\225\255\230\255\173\002\248\002\067\003\142\003    \217\003\036\004\111\004\186\004\005\005\080\005\155\005\230\005    \049\006\124\006\199\006\018\007\232\255\237\255\234\255\231\255    \236\255";

The extra whitespaces in the string constants are crucial.  The intent
of the output of ocamllex was that they would *not* be included in the
strings, but cpp mangles those strings so that they are included in
the strings, thereby producing a broken lexer.

-=-
; Kenneth Oksanen, email: cessu@iki.fi, http://www.iki.fi/~cessu
((lambda(a) (a a((lambda(a)(lambda()(set! a(+ a 1))a))1)))(lambda(a c)
((lambda(b) (newline)(write b)(a a((lambda(c)(lambda()(c c)))(lambda(a)
((lambda(c) (if(=(modulo c b)0)(a a)c))(c))))))(c)))) ; Scheme me!
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