Re: lambda, ->, haskell, and so on

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