From: "Douglas A. Seifert" <doug@...>
Date: 2007-11-14T12:16:17+09:00
Subject: Re: recursion with blocks

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Pat Maddox wrote:
> On Nov 13, 2007 4:15 PM, James Edward Gray II <james@grayproductions.net> wrote:
>   
>> On Nov 13, 2007, at 6:01 PM, Mike Perham wrote:
>>
>>     
>>> You aren't actually recursing inside the block,
>>> just using the block as a conditional.  I was trying to figure out how
>>> to recurse inside the block.
>>>       
>> Yeah, I was just using the block inside a recursive method.  You are
>> right.
>>
>> Can you elaborate on what you mean by "recurse inside a block?"  I'm
>> having trouble thinking of an example.
>>
>> James Edward Gray II
>>
>>
>>     
>
> I think he means something like this?
>
> fact = lambda {|val| return 1 if val <= 0; val * fact[val - 1] }
> fact[4]  => 24
>
> but I'm not sure...
>
> Pat
>
>   
This works:

irb(main):001:0> fact = lambda {|val| val <= 0 ? 1 : val * fact[val-1] }
=> #<Proc:0x00002b8724682be0@(irb):1>
irb(main):002:0> fact.call(4)
=> 24
irb(main):003:0> fact.call(6)
=> 720


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