From: "David A. Black" <dblack@...>
Date: 2008-05-25T20:46:25+09:00
Subject: Re: lambda, ->, haskell, and so on

Hi --

On Sun, 25 May 2008, Phlip wrote:

>>>  assert_yin_yang proc{ q +=  0 }, 'it broke!',
>>>                  proc{ q == 42 }
>>> 
>>> That sorta obviates my standard advertizing jingle - more assert bang for 
>>> less coding buck! 'proc' ain't DRY there...
>> 
>> I don't think I'd describe those two 'proc's as a case of repeating
>> yourself, since each of them is serving the minimal purpose that
>> 'proc' can serve. Or, to put it another way, proc { q == 42 } is in no
>> way a repetition of proc { q += 0 }.
>
> You are correct that the most important aspect of the DRY rule is behavior, 
> so to your trained Ruby eye the payload - q == 42 and q += 0 - are indeed 
> distinct. In this way, 'proc' is structure, which is harder and less useful 
> to DRY up.
>
> Yet if I'm trying to sweeten the syntactic sugar of my assertion, the 'proc' 
> simply adds excess verbiage that adds nothing to readability. So the ->

My view is that it isn't excess, any more than in this case:

   class A
     ...
   end

   class B
     ...
   end

the second appearance of 'class' is excess.

> operator (or whatever it arrives as) will indeed be much safer than _{}!

I'm still hoping it might arrive as "lambda" :-)


David

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