procmail
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Re: protecting trailing space

1996-08-08 15:54:53
dattier(_at_)wwa(_dot_)com (David W. Tamkin) writes:
This probably is a question for someone who knows how to read the source
code, or for Stephen himself.

Now if you had said, "...someone who is able to _comprehend_ the source..."
then the two groups would be equal.


I have several conditions in my .procmailrc that search for an expression
that ends in a trailing space.  In order not to delete the trailing space
accidentally, I write those conditions like this:

 * whatever else[ ]

It occurred to me that the use of brackets might not be as efficient there
as parentheses:

 * whatever else( )

or even

 * whatever else ()

From my looking at the source, the last two should be equal in
efficiency, and except for a trace differance in regcomp time, should
match at the same speed as a solitary trailing blank.  The character
class version "[ ]" will be slower, but how much slower I'm not going
to tell you (to paraphrase a Monty Python skit).

Of course, I suspect that neither you nor your sysadmin will ever
notice the differance in speed, and given that 99% of all systems are
I/O bound and not CPU bound, the system is incredibly unlikely to
notice either.  I can't complain though, as I also go to various
extremes to eek out every last bit of possible performance.  Ah well...

Philip Guenther

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