From: Mike Harris <GENIE@...>
Date: 2006-09-28T07:24:22+09:00
Subject: Re: Injecting truth

Ken Kunz wrote:

>I had a scenario arise today where I needed an iterator with similar
>semantics as Enumerable#all?, but non-short-circuiting. We came up with
>a fairly elegant solution (imho), so I thought I'd be a good rubyzen
>and share :)
>
>1) First... the standard #all? (short-circuits):
>
>irb> (1..5).all? { |i| puts i; i < 3 }
>1
>2
>3
>=> false
>
>2) Non-short-circuiting version (injecting truth):
>
>irb> (1..5).inject(true) { |retval, i| puts i; retval &&= (i < 3) }
>1
>2
>3
>4
>5
>=> false
>
>3) One more way (though I like #2 better)
>
>irb(main):016:0> (1..5).partition { |i| puts i; i < 3 }.last.empty?
>1
>2
>3
>4
>5
>=> false
>
>-Ken
>
>
>
>  
>
Also, with #2, obviously your way works, but the &&= isn't neccesary, a 
&& has the intended effect, since the result of the block is put in the 
accumulator.  Again, it doesn't matter at all, I'm mostly just writing 
to avoid doing work.