Version française
Home     About     Download     Resources     Contact us    

This site is updated infrequently. For up-to-date information, please visit the new OCaml website at

Browse thread
Patterns that evaluate
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: 2007-02-13 (22:14)
From: Jon Harrop <jon@f...>
Subject: Re: [Caml-list] Patterns that evaluate
On Tuesday 13 February 2007 22:04, Jacques Carette wrote:
> I recently wrote some ocaml code which "worked", but not as I
> intended...  The test cases I tried worked, but I should have tested
> harder.  Apparently I was under the mistaken impression that OCaml's
> pattern-matching was more "first class"!  So I wrote (in part):
> let buildsimp cast e f1 f2 = fun e1 -> fun e2 -> match (e1,e2) with
>                                                  | ({st = Some e}, _) -> e2
> and I expected it to work.  Only a code review by a colleague 'found'
> this bug in my code.
> Question: would it be a difficult extension?  This seemed so "natural",
> I just "used" the feature before it was quite there yet ;-).

F# just introduced active patterns, which does what you want AFAIK. Of course, 
you must disambiguate that from the OCaml's current interpretation of the 
above (binding "e").

Dr Jon D Harrop, Flying Frog Consultancy Ltd.
OCaml for Scientists