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From: Jon Harrop <jon@ffconsultancy.com>
Organization: Flying Frog Consultancy Ltd.
To: O'Caml Mailing List <caml-list@yquem.inria.fr>
Subject: Parsing 64-bit ints in 32-bit OCaml
Date: Sat, 7 Mar 2009 17:28:56 +0000
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X-Spam: no; 0.00; ocaml:01 failwith:01 ocaml's:01 parser:01 integers:01 frog:98 parsing:01 integer:01 ints:01 functions:01 int:01 int:01 breaks:02 match:02 div:97 


I'm just trying to write efficient functions for div and mod by three. I'd 
like to handle 32- and 64-bit machines with the same code so I tried:

  let gcd3 = match Sys.word_size with
    | 32 -> 715827883
    | 64 -> 3074457345618258603
    | _ -> failwith "Unknown word size"

That works perfectly in 64-bit but breaks OCaml's parser in 32-bit, which dies 
with:

  Integer literal exceeds the range of representable integers of type int

As a workaround, I replaced it with:

  | 64 -> Int64.to_int 3074457345618258603L

Is there a better workaround?

-- 
Dr Jon Harrop, Flying Frog Consultancy Ltd.
http://www.ffconsultancy.com/?e