From: Ryan Leavengood <leavengood@...>
Date: 2005-11-06T16:32:33+09:00
Subject: Re: Generation of Unique Symbols

On 11/6/05, Eric Hofreiter <erichof425@yahoo.com> wrote:
>
> But this is obviously not very efficient.  Is there a better way to do this?  If not I may just
> go back to good old integers.

For the fun of it I decided to benchmark your way versus mine. For
100,000 calls here are the results on my reasonably fast Windows XP
laptop:

                user     system      total        real
eval        1.766000   0.016000   1.782000 (  1.782000)
intern      0.531000   0.000000   0.531000 (  0.531000)
:AAAAFRYE
:AAAAFRYE

As you can see using intern is more than 3 times faster. But it took
100,000 calls to even get reasonable comparison numbers, so both are
quite fast for normal use.

Also as you can see I print out the symbols at the end and that is a
pretty interesting symbol after 100,000 iterations :)

Here is the code:

require 'benchmark'

$sym1 = :AAAAAAAA
def next_sim1
  $sym1 = eval(":" + $sym1.id2name.next)
end

$sym2 = :AAAAAAAA
def next_sim2
  $sym2 = $sym2.to_s.next.intern
end

if $0 == __FILE__
  Benchmark.bm(10) do |bx|
    bx.report('eval') { 100000.times { next_sim1 } }
    bx.report('intern') { 100000.times { next_sim2 } }
  end
  p $sym1
  p $sym2
end
__END__

Ryan