cvs commit: perlfaq perlfaq6.pod

cvsuser     05/08/10 08:55:08

  Modified:    .        perlfaq6.pod
  Log:
  * spelling fixes
  
  * Why does using $&, $`, or $' slow my program down?
     + Anno Siegel updated the answer for recent speed
     modifications
  
  Revision  Changes    Path
  1.35      +15 -9     perlfaq/perlfaq6.pod
  
  Index: perlfaq6.pod
  ===================================================================
  RCS file: /cvs/public/perlfaq/perlfaq6.pod,v
  retrieving revision 1.34
  retrieving revision 1.35
  diff -u -r1.34 -r1.35
  --- perlfaq6.pod	6 Aug 2005 06:55:54 -0000	1.34
  +++ perlfaq6.pod	10 Aug 2005 15:55:08 -0000	1.35
  @@ -633,14 +633,20 @@
   (contributed by Anno Siegel)
   
   Once Perl sees that you need one of these variables anywhere in the
  -program, it provides them on each and every pattern match.  That means
  -that on every pattern match the entire string will be copied, part of
  -it to $`, part to $&, and part to $'.  Thus the penalty is most severe
  -with long strings and patterns that match often.  Avoid $&, $', and $`
  -if you can, but if you can't, once you've used them at all, use them
  -at will because you've already paid the price. Remember that some
  -algorithms really appreciate them.  As of the 5.005 release, the $&
  -variable is no longer "expensive" the way the other two are.
  +program, it provides them on each and every pattern match. That means
  +that on every pattern match the entire string will be copied, part of it
  +to $`, part to $&, and part to $'. Thus the penalty is most severe with
  +long strings and patterns that match often. Avoid $&, $', and $` if you
  +can, but if you can't, once you've used them at all, use them at will
  +because you've already paid the price. Remember that some algorithms
  +really appreciate them. As of the 5.005 release, the $& variable is no
  +longer "expensive" the way the other two are.
  +
  +Since Perl 5.6.1 the special variables @- and @+ can functionally replace
  +$`, $& and $'.  These arrays contain pointers to the beginning and end
  +of each match (see perlvar for the full story), so they give you
  +essentially the same information, but without the risk of excessive
  +string copying.
   
   =head2 What good is C<\G> in a regular expression?