From: James Edward Gray II <james@...>
Date: 2006-01-14T05:03:30+09:00
Subject: Re: [QUIZ.SUMMARY] Dice Roller (#61)

On Jan 13, 2006, at 1:57 PM, J. Ryan Sobol wrote:

> On Jan 12, 2006, at 10:22 AM, Christian Neukirchen wrote:
>
>> Matthew Moss <matthew.moss.coder@gmail.com> writes:
>>
>>> @dice = eval "lambda { #@src }"
>>>
>>> The morphed express is saved away in a lambda, which allows  
>>> Christian to
>>> reevaluate the expression repeatedly without performing those  
>>> substitutions
>>> every time roll is called.
>>
>> I could have evaluated @src each time without substituting anew,  
>> but a
>> lambda only makes it need to *parse* once.
>
> Hey Christian,
>
> I didn't have time to write my own solution to quiz #61, so I'm  
> going over yours, which is similar to what I was kicking around in  
> my head.  Unfortunately, I confused by your eval statement, which  
> is wrapped over a new Proc object.  Instead, why not wrap the  
> lambda around the eval like so?
>
> @dice = lambda { eval @src }
>
> The both _seem_ to produce the same output, yet conceptually, my  
> approach makes more sense to me.  Perhaps I'm missing something  
> crucial in my statement like...
>
> Does eval parse @src for each call() message?

Yes.  You pass lambda() a block of code that is executed each time  
the code it called.

James Edward Gray II