On Tue, 18 Mar 2003 23:44:51 +0000
Glynn Clements
The point is that if:
a) you want multiple callback procedures for a single event, and b) you want to be able to de-register individual callbacks,
then there has to be some way of specifying *which* callback procedure you wish to de-register
Yes, this is clear; it's easy to get misunderstood on the web. I was just saying to Daan, in the post you answered, that having multiple callbacks, and so having to return something in the act of registration, does not mean that one can't use nicer syntaxes (syntaxen?). If you want button [onClick =: doSomething] you can have it, you will find your result, the unregister action, among other fields in the result type. If you don't want to put it into the "Button" datastructure, things get really complicated, yes it's so. Notice that you are not requiring the user to pass a FunPtr to the registration action anywhere, nor using it in the CGA, if the toolkit provides multiple callbacks. BTW, this behaviour would feel somewhat right to me: if you have a "preferred" callback (or you are working with just one), this is the one you'll find in the button's "unregister callback" field. Vincenzo -- Teatri vuoti e inutili potrebbero affollarsi se tu ti proponessi di recitare te [CCCP]