Why /(word){0}/ does not work?

Hi,

I use a monitoring application, which allow use of perl regexp to
filter which instance of something I want to monitor.
In some case I want to monitor everything except one instance.
Lets say it's every filesystem except /temp.
The monitoring software allow perl regexp but not negating them.

So I tried /(\/temp){0}/ but it doesnt work (every filesystem is
monitored /temp included).

Why is it it doesnt work?
Is /^(?:(?!\/temp).)*$/ my only chance to do this right? Looks insanly
obfuscated to me, but if you this it's the rite way to do it, I may
try to understand it ....

Regards,
Chacallot.

Re: Why /(word){0}/ does not work?

chacallot@gmail.com wrote:
> So I tried /(\/temp){0}/ but it doesnt work (every filesystem is
> monitored /temp included).

The usual terminology for REs is "to match", not "to monitor". Therefore I
am not sure about if you are complaining that /(\/temp){0}/ matches '/temp'
or doesn't match '/temp'.

However, _I_ read /(\/temp){0}/ as zero consecutive matches of /(\/temp)/
which would match exactly the same strings as the empty RE //, e.g. it will
match every string.

> Why is it it doesnt work?

But it does work. It matches zero repetitions of the preceeding RE.

jue

Re: Why /(word){0}/ does not work?

chacallot@gmail.com wrote:

> The monitoring software allow perl regexp but not negating them.


Does it allow you to set an action of "ignore"?

If so, set a regex for /temp - action == ignore
Then set a regex for the rest of life, doing what you want for it.



--
Just because I've written it doesn't mean that
either you or I have to believe it.

Re: Why /(word){0}/ does not work?

>>>>> "chacallot" == chacallot writes:

chacallot> So I tried /(\/temp){0}/ but it doesnt work (every filesystem is
chacallot> monitored /temp included).

Indeed. The string "a" matches /a{0}/, because "a" has a match for zero
instances of 'a', which is the same as the empty string, which every string
has.

Why would you expect it to do something different?

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095

Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
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Re: Why /(word){0}/ does not work?

Randal L. Schwartz schreef:
> chacallot:

> chacallot> So I tried /(\/temp){0}/ but it doesnt work (every
> filesystem is chacallot> monitored /temp included).
>
> Indeed. The string "a" matches /a{0}/, because "a" has a match for
> zero instances of 'a', which is the same as the empty string, which
> every string has.
>
> Why would you expect it to do something different?

I actually like chacallot's train of thought. He/She wants the number of
(possible) matches to be 0.

0 * 0 = 0, so why is a beggar happy if there are zero days on which he
received zero Euros?


chacallot, did you try this? !/^\/temp\//

If your software only allows unnegated Perl /regexen/:

/^(?!=\/temp\/)/

--
Affijn, Ruud

"Gewoon is een tijger."