From: "J. Ryan Sobol" <ryansobol@...>
Date: 2006-01-14T04:57:19+09:00
Subject: Re: [QUIZ.SUMMARY] Dice Roller (#61)

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?  Or does the parsing  
happen on initialization of the Proc (like I would expect)?  I  
suppose I could trace the execution using the debugger, but I'm  
unaware how to step inside a Kernel method like eval or lambda with it.

~ ryan ~