Re: [Sc-devel] update method for Functions

[Sciss <contact@xxxxxxxx>]

i second that. !but! could we please use the general form of Updater,  
so that it becomes:

	update { arg ... args;
		this.valueArray( args );
	}

this way we don't limit the usage to two arguments. To give an example:

m = Object.new;
m.addDependant({ arg obj, what, x, y; [ obj, what, x, y ].postln });
m.changed( \move, 11, 22 );

ciao, -sciss-



Am 23.12.2007 um 17:27 schrieb Iannis Zannos:

> Hello,
>
> I would like to propose the addition of method "update" for the  
> Function class as follows:
>
>     update { arg theChanged, theChanger;
>         ^this.value(theChanged, theChanger);
>     }
>
> This makes it possible to add a Function directly as dependant to  
> any Object. This has the effect of radically generalizing and  
> simplifying the usage of the Observer pattern: A Function can act  
> as simple and direct "Adapter" to react to a change happening in  
> any object that wishes to notify its dependants with:
>    this.changed(whatChanged, this)
>
> One of the many uses I have found for this is for example the  
> ability to add functions to execute when a Server starts or quits,  
> or when any Node or EventStreamPlayer ends (code attached). It is  
> part of a small reliable scheme for broadcasting any changes in the  
> run state of Nodes and EventStreamPlayers with any object that  
> might need to be notification.
>
> If this could be included in 3.2 then I would like to document it  
> in the upcoming sc-book.
>
> Iannis Zannos
>
>   
> ====================================================================== 
> =
>
>     onEnd { | argFunc |
>         var cmdPeriodFunc;
>         NodeWatcher.register(this);
>         // this is needed to add this to catch synths stopped by  
> Command-Period:
>         cmdPeriodFunc = {
>             NodeWatcher.unregister(this);
>             CmdPeriod.remove(cmdPeriodFunc);
>             argFunc.value;
>         };
>         CmdPeriod.add(cmdPeriodFunc);
>         // This evaluates argFunc when notified by NodeWatcher
>         this.addDependant { | me, whatHappened |
>             if (whatHappened == \n_end) {
>                 argFunc.(this);
>                 this.removeDependant(argFunc);
>                 // see CmdPeriod above
>                 CmdPeriod.remove (cmdPeriodFunc);
>             }
>         };
>     }
> }
>
> + EventStreamPlayer {
>     onEnd { | argFunc |
>         this.addDependant { | me, whatHappened |
>             if (whatHappened == \stopped) {
>                 argFunc.(this);
>                 this.removeDependant(argFunc);
>             }
>         }
>     }
>
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