From: L7 <jesse.r.brown@...>
Date: 2006-08-18T23:05:11+09:00
Subject: Question on speed

Based on the following snippet:

File.open(name).each { |line|
   case line
   when /not found/, /^[gBbTi]/
      next
   when /^S/
      # start or stop condition
   when /^I/
      # iteration indicator
   else
      # actual data
   end
}


In the first when, (/not found/, /^[gBbTi]/) is there any benefit in
setting up the statement in either of the following ways?

when /^[gBbTi]/, /not found/
   Put the short circuit one first (expected to happen more often than
'not found')

OR

when /^g/, /^B/, /^b/, /^T/, /^i/, /not found/
   Separate each operation into it's own portion of the test (ordered
by expected frequency)

I guess this is really a question of 'how does ruby handle the multiple
arguments to a case statement?'.
Are they taken in order or all compiled to a single expression before
ever being evaluated?

Thanks for any insight.