From: Tom Jordan <tdjordan@...>
Date: 2006-08-16T06:24:23+09:00
Subject: block equality

Is there a way to compare two blocks with each other?

If you promote a block into a Proc, how would you know that the
original block was the same?

This is what I want to do

(1..10).each do
  once { puts "Hi Tom"}
end

I've tried to implement once like this

class << self
	def once(&block)
		@ids ||= {}
		block.call unless @ids.key? block.object_id
		@ids[block.object_id] = :true
		puts @ids.keys.join(', ')
	end
end

I've even tried a varient using == and ===

def l(&b)
  @t ||= b
  puts b == @t
  puts b === @t
  @t = b
end

(1..2).each { l{x=1} }

output:
true
true
false
false

How can you compare two procs that have the same body?

Thanks,
-- Tom.

-- 
"Nothing will ever be attempted, if all
 possible objections must first be
 overcome." - Samuel Johnson

"Luck is what happens when
 preparation meets opportunity." - Seneca