From: "bparanj@..." <bparanj@...>
Date: 2008-04-30T13:30:03+09:00
Subject: Question on Procs

What is the difference between this:

list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

def make_filter(predicate, list)
    result = []
    list.each do |element|
      result << element if predicate.call(element)
    end
    result
end

require 'rubygems'
require 'facets/integer/ordinal'

filter_ths = make_filter( lambda { |x| x.ordinal =~ /th$/ ? true :
false }, list)

p filter_ths

and this:

list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

def make_filter(predicate)
  lambda do |list|
    result = []
    list.each do |element|
      result << element if predicate.call(element)
    end
    result
  end
end

require 'rubygems'
require 'facets/integer/ordinal'

filter_ths = make_filter( lambda { |x| x.ordinal =~ /th$/ ? true :
false })

p filter_ths.call(list)

I am not clear on the advantage of returning proc object vs just the
result as an array. TIA.