Ok good. Although the list in #3 never gets assigned to a variable, the interpreter certainly knows about it. So i was thinking about it in an analogous manner to when you have something like:

   if ( $x =~ /#some regex/o ) {
# or
   if ( $x =~ /#some constant regex/ ) {
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Those regex's are only compiled once, whatever that means. I guess it means that the interpreter stores the info away somewhere to be readily available for use later.