From: Gavin Kistner <gavin@...>
Date: 2005-05-26T23:01:04+09:00
Subject: Re: Invoking a Class block on an Instance

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On May 26, 2005, at 2:57 AM, Pit Capitain wrote:
> Gavin Kistner schrieb:
>> Unfortunately, I can't figure out how to get an instance of a  
>> class  to invoke a block stored in its parent class, using the  
>> scope of the  instance for the block. In JS this would be easy,  
>> but I don't yet  grok how to have Ruby run a set of code on any  
>> arbitrary scope (while  passing parameters to that code).
>
> executing a code block in the context of an object is normally done  
> via instance_eval, but I, too, couldn't find a way to pass  
> parameters to the block.
>
> One workaround is to create methods for the states. If you change  
> the following methods of FiniteStateMachine, it should work:

Thanks for this; it solved my current problem.

I would still like to know how (if it's possible) I can do the Ruby  
equivalent of this JS code:

     var addSome = function( addend ){ return this.val + addend }

     var obj1 = new Object;
     obj1.val = 10;

     var obj2 = new Object;
     obj2.val = 100;

     var sum1 = addSome.call( obj1, 10 ); //20
     var sum2 = addSome.call( obj2, 10 ); //110

Is this the problem people are talking about when they say that Ruby  
doesn't have "first class" functions/methods?

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