From: Phrogz <gavin@...>
Date: 2006-12-27T13:15:06+09:00
Subject: Re: Peculiar Behavior for a Newby to Undertstand

Rob Biedenharn wrote:
> The value of the #step method is the initial value so that is being
> returned from a.show_primes and presumably printed by whatever you're
> using to interpret your statements (like irb):

As a simple example:

  irb(main):001:0> puts 1.step( 2 ){ print "a " }
  a a 1
  => nil

In the above, the block is called twice, and prints out 'a ' each time.
Then the return value of the step method (the initial value) it passed
to the puts function, which prints it out.

You're seeing your first non-even value as the return, since the step
method is the last call in your show_primes method.

One other comment - the pairing of methods you have inside your class
seems odd, given Ruby's built-in classes for numbers. Instead of your
class wrapper, I might personally place those methods as:

  class Integer
    def is_prime?
      # ...
    end
  end

  def show_primes( lower, upper )
  end

Although, since I'm personally not a big fan of 'global' functions, I
might even do:

  class Integer
    def self.show_primes( lower, upper )
      # ...
    end
  end