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Option functions (or lack thereof) + operator for composition
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Date: | 2010-11-16 (11:51) |
From: | David Allsopp <dra-news@m...> |
Subject: | RE: [Caml-list] Option functions (or lack thereof) + operator for composition |
Serge Le Huitouze wrote: > 1. Option type > **************** > It seems that there is no predefined function to test an "'a option" for > being specifically "None" or "Some _". This seems to be confirmed by the > very existence of: > http://ocaml-lib.sourceforge.net/doc/Option.html > which defines such functions ("is_none" and "is_some"). > I found it weird to be forced to use "match" expressions in my code for > doing that, e.g.: > * let curSelectedRow = ref None in > * let updateButtonsStatus () = > * button_remove#misc#set_sensitive > * (match !curSelectedRow with None -> false | _ -> true) > * in > * ... > > I could add the OCaml library mentioned above, but I don't know how to do > it (and where to find it) and, since my code is supposed to go into some > other code, I'd prefer avoiding adding yet another dependency to it... ExtLib is well-worth having and it's very easy to install (just run ocaml install.ml in its source tree - findlib recommended but I've got a feeling that it can install without findlib as well). It's also very stable, feature-wise, so you're not really adding a tricky dependency. It's now hosted on Google Code at http://code.google.com/p/ocaml-extlib/downloads/list You might also take a look at the batteries project (http://batteries.forge.ocamlcore.org) which I believe includes most if not all of ExtLib. David