From: Ken Kunz <kennethkunz@...>
Date: 2006-09-28T07:10:14+09:00
Subject: Injecting truth

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