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| Date: | -- (:) |
| From: | Mattias Waldau <mattias.waldau@a...> |
| Subject: | Re: [Caml-list] infinity matches all |
There is a patch which warns for unused variables. Then you would have got the message that the variable "infinity" isn't used. It regulary finds bugs for me. -- Mattias Xavier Leroy wrote: >>Can anyone explain the following behavior of match when used with infinity? >> >># match "foo" with infinity -> "bar";; >>- : string = "bar" >> >>This shouldn't even typecheck. It seems to treat infinity as equivalent >>to "_". This behavior comes up in version 3.06. > > > This is probably in the FAQ somewhere. What confuses you is that this > occurrence of "infinity" is just a variable that is bound by the > matching; it's not a constructor, and it's not a constant. Hence, you > code is equivalent (by renaming) to > > match "foo" with s -> "bar";; > > and indeed to > > match "foo" with _ -> "bar";; > > since _ behaves like a variable that isn't referenced in the r.h.s. > > If you intend to match against the value of floating-point infinity, do > > match e with x when x = infinity -> ... > > - Xavier Leroy > > ------------------- > 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 > ------------------- 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