ietf-mta-filters
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Re: variables draft (draft-homme-sieve-variables-00.txt)

2003-04-08 16:32:06

[Tim Showalter]:

  I implemented a mostly-linear time glob algorithm by implementing
  minimal matching left-to-right.  I am opposed to any semantic that
  would result in pattern matching being fairly expensive
  (specifically, any algorithm that results in * being recursive is
  bad).
  
  If I had done minimal-matching right-to-left, would the result
  have been greedy?  (This would resolve my objection.)

yes.  just reverse both strings to see this.  here's an example:

"ababbab" ~ "*a*b?*" => [ "ab", "b", "a", "b" ]  (greedy)
"babbaba" ~ "*?b*a*" => [ "b", "a", "b", "ba" ]  (minimal)

or the other pair:
"babbaba" ~ "*?b*a*" => [ "babb", "a", "", "" ]  (greedy)
"ababbab" ~ "*a*b?*" => [ "", "", "a", "bbab" ]  (minimal)

-- 
Kjetil T.                       |  read and make up your own mind
                                |  http://www.cactus48.com/truth.html

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