From: jweirich@...
Date: 2000-11-14T11:30:42+09:00
Subject: [ruby-talk:6336] Another Smalltalk control structure idea

Just as the if_none / when_missing / nil_gives discussion has died
down ...

Here's another control structure idea from Smalltalk that I didn't see
in Ruby.

    module Enumerable
      def inject (initial_value)
        result = initial_value
        each { |item| result = yield (item, result) }
        result
      end
    end

    # Example Usage

    [1,2,3].inject(0) {|item,sum| item+sum}
        #=> 6
    [2,3,4,5].inject(1) {|item,prod| item*prod}
        #=> 120
    [%w(a b), %w(b c)].inject([]) {|item,result| item | result}
        #=> ["b", "c", "a"]

Smalltalk's version is called inject:into:.  I'm not particularly
happy about the name (its probably too Smalltalk'ish for Matz :-), but
I have found the functionality useful.

-- 
-- Jim Weirich     jweirich@one.net    http://w3.one.net/~jweirich
---------------------------------------------------------------------
"Beware of bugs in the above code; I have only proved it correct, 
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)