Version française
Home     About     Download     Resources     Contact us    
Browse thread
Static exception analysis or alternative to using exceptions
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: -- (:)
From: Christophe Raffalli <christophe.raffalli@u...>
Subject: Re: [Caml-list] Static exception analysis or alternative to using exceptions

> It would be nice if the possible exceptions of a function would be part
> of the type. E.g.
>
> let f1 () = raise Not_found
> val f1 : unit -> 'a [ Not_found ]
>
> let f2 () = try f1 () with Not_found -> ()
> val f2 : unit -> unit
>
> let f3 f = try f () with Not_found -> ()
> val f3: (unit -> 'a [< Not_found | 'B ]) -> 'a [ 'B ]
>
> and so on.
>   
This is what PML does ... and what is nice is that is does not even
require the exception to be garded ...
>
> Someone would have to write a new type system for that though.
>   
Yes, but this require very little new technology : a function having one
type or two as return type is basically the same ...
and polymorphic variant are very well suited to be the default practice
for exception (as in your f3 example).

The only questions (I think) are
- complexity of the algorithm (I think it shoud be OK)
- readability of inferred types (one could hide exception types by
default ?)
 
Cheers,
Christophe

> MfG
>         Goswin
>
> _______________________________________________
> Caml-list mailing list. Subscription management:
> http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
> Archives: http://caml.inria.fr
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>