From: RichardOnRails <RichardDummyMailbox58407@...>
Date: 2011-01-23T13:50:24+09:00
Subject: Easiest way in Ruby to express "given this, set target to this if nil or undefined, else increment by this"

The following works,  but I'd prefer not to have to class values:

class Z
    def self.show_z
	@@zz ||= 0; @@zz += 1
	puts @@zz
    end
end
Z.show_z	# => 1
Z.show_z	# => 2

I tried this:

$h = Hash.new(:y)
def show_y
    $h[:y] ||= 0; $h[:y] += 1 # => Error msg # Line 18
    puts $h[:y]
end
show_y
show_y

but it doesn't pass muster with Ruby 1.8.6.  I get a complaint about
the first line in show_y, which makes no sense IMHO:

TestOrEqual_operator.rb:18:in `show_y': undefined method `+'
for :y:Symbol (NoMethodError)
	from TestOrEqual_operator.rb:21

Also, I'd be able to use a succinct version of this without resorting
to globals.

An ideas?

Thanks in Advance,
Richard