From: ts <decoux@...>
Date: 2001-02-28T19:26:06+09:00
Subject: [ruby-talk:11759] Re: Comparison Caching

>>>>> "B" == Ben Tilly <ben_tilly@hotmail.com> writes:


 This is what it do, except here

B>   def visited? (this, that)
B>     if @seen[this].nil?
B>       @seen[this] = [ that ]
B>     else
B>       return true if @seen[this].include? that
B>       @seen[this].push that
B>     end
B>     false
B>   end


     def visited?(this, that)
        this, that = that, this if this > that
        return true if $seen[[this, that]]
	$seen[[this, that]] = true
        false
     end


  $seen is a thread local variable.

 I don't know which version is faster.


Guy Decoux