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Date: | 2002-06-21 (12:11) |
From: | Pierre Weis <pierre.weis@i...> |
Subject: | Re: [Caml-list] printf arguments |
> In trying to write a wrapper around printf for debug message logging, > (a la syslog), I am coming across the following problem: > > # let myprintf fmt = if (true) then Printf.fprintf stdout fmt;; > val myprintf : (unit, out_channel, unit) format -> unit = <fun> If cond then expr == if cond then expr else () [...] > so the myprintf function above does not have the same type as the original > fprintf. Note that removing the if clause returns us to the proper type: > > # let myprintf fmt = Printf.fprintf stdout fmt;; > val myprintf : ('a, out_channel, unit) format -> 'a = <fun> If you want to preserve the original typing of printf, you must imperatively use a tail call to printf (due to the typing discipline of string format). Regards, Pierre Weis INRIA, Projet Cristal, Pierre.Weis@inria.fr, http://pauillac.inria.fr/~weis/ ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners