From: ts <decoux@...>
Date: 2002-11-14T01:58:09+09:00
Subject: Re: Newbie Question.

>>>>> "m" == montana  <montana@buc99.bsd.st> writes:

m> 3.times {|i| puts i}

 Well, the method Integer#times iterate self times (3 in your case) and for
 each iteration call the block, given it the current value.

 This method can be written (very badly)

   class Fixnum
      def times
         i = 0
         while i < self
            yield i
            i += 1
         end
      end
   end


m> something do |line|
m>   #process something and line here
m> end

m> Is this correct? You take some object named something and process it's
m> values in the do-end statement using the variable list?? 

 not really, `something' is a method and this method call the block with
 some value.

 For example if you want to read a file, you write

  IO.foreach('file') do |line|
     # do something with line
  end

 the method IO::foreach open the file given in argument, read each line and
 call the block, given it the current line. At the end, IO::foreach close
 the file 

m>  But yield calls the block to do some value manipulation?

 yield call the block with some values, and the block make some computation
 with these values


Guy Decoux