From: Gavin Sinclair <gsinclair@...>
Date: 2002-09-06T10:36:59+09:00
Subject: Re: Ruby aesthetics

> On Fri, Sep 06, 2002 at 02:08:19AM +0900, Tobias Peters wrote:
>> This just came to my mind:  Since ruby allows for nested singleton
>> methods, you could probably write:
>>
>>   def sqrt(x)
>>     o = Object.new
>>     def o.good_enough(g1,g2)
>>       ((g1 - g2).abs / g2) < .001
>>     end
>>     def o.improve(guess)
>>       average(guess, x/guess)
>>     end
>>     def o.sqrt_iter(g1,g2)
>>       good_enough(g1,g2) ? g2 : sqrt_iter(g2, improve(g2))
>>     end
>>     o.sqrt_iter(1.0, 2.0)
>>   end
>
> Most defs within defs can also be resolved using procs.
>
> def sqrt(x)
>   good_enough = proc { |g1,g2| ((g1 - g2).abs / g2) < .001 }
>   improve     = proc { |guess| average(guess, x/guess) }
>   sqrt_iter   = proc { |g1,g2| good_enough[g1,g2] ? g2 : sqrt_iter[g2,
> improve[g2]] } sqrt_iter[1.0, 2.0]
> end

This was exactly my code that led to Tobias's example!

Can anyone comment on the performance difference between procs and
singleton definitions?

> --
> Alan Chen

Gavin