Re^2: Where can I find more examples of use of Special Backtracking Control Verbs?

\K is the basis for a variable length positive look behind assertion. The case discussed here implements a variable length negative look behind assertion, which in Perl must always be emulated in some way (ATM).

Give a man a fish: <%-{-{-{-<

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Re^3: Where can I find more examples of use of Special Backtracking Control Verbs? by Eily (Monsignor) on Nov 06, 2018 at 22:58 UTC
Ahem, yes. I failed to see that. Thanks pointing that out. On a completly far-fetched note, now that I think I understand the (SKIP)(FAIL) pattern, it seems to me that it only covers the subset of negative look behind assertions that do not come after any character has been matched. For example: `/^(.{5})+(?<!abc)d/` (which is the same as matching `/d(?!cba)(.{5})+$/` on the reverse string) can't be rewritten using the (SKIP)(FAIL) pattern (AFAICT). I'm sure this is a problem people stumble upon all the time :P	[reply] [d/l] [select]
Re^4: Where can I find more examples of use of Special Backtracking Control Verbs? by AnomalousMonk (Archbishop) on Nov 07, 2018 at 19:42 UTC
For example: `/^(.{5})+(?<!abc)d/` ... can't be rewritten using the (SKIP)(FAIL) pattern ...* I don't see how it could be done, but I'm still looking. Certainly the trick has its limits. Still, it's handy in a few situations. However, variable width negative look-behind is, perhaps fortunately, not something one tends to really need very often. :) Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]