From: William James <w_a_x_man@...>
Date: 2009-01-12T09:14:23+09:00
Subject: Re: functional programming

Pascal J. Bourguignon wrote:

> There's a difference between (def smallest(x) ; x ; end) 
> and (smallest = (lambda { |x| x }))
> 
> In the former case, you can write (smallest [1,2,3])
> in the later you can't:
> 
> 
> irb(main):001:0> (def smallest(x) ; x ; end) 
> (def smallest(x) ; x ; end) 
> nil
> irb(main):002:0> (smallest [1,2,3])
> (smallest [1,2,3])
> [1, 2, 3]
> irb(main):003:0> (smallest = (lambda { |x| x }))
> (smallest = (lambda { |x| x }))
> #<Proc:0x0035fdf4@(irb):3>
> irb(main):004:0> (smallest [1,2,3])
> (smallest [1,2,3])
> (irb):3: warning: multiple values for a block parameter (3 for 1)
> 	from (irb):4
> [1, 2, 3]

foo = proc{|x| "#{x.size} items: #{ x.join ' & ' }" }
    ==>#<Proc:0x0282ded8@(irb):15>
foo.call( [2,3,4] )
    ==>"3 items: 2 & 3 & 4"
foo[ [2,3,4] ]
    ==>"3 items: 2 & 3 & 4"