Front page | perl.perl5.porters |
Postings from February 2020
Karl Williamson <public@khwilliamson.com> wrote:
:I can't think of any legitimate purposes for quantifying any zero-length
:assertion.
:
:Using the general form of expressing them, I don't see a difference
:between any of {0,1} {0,2} {0,3} ... {0, infinity}. They are all
:no-ops, except possibly for side effects in code blocks, as Grinnz
:pointed out on IRC.
:
:Nor do I see any difference between {1,1} {1,2} ... {2,2} {2,3} ...
:in programs that aren't in error.
:
:So why can't we optimize all such constructs to their minimal forms.
:That would make \K+ optimize to effectively \K{1,1}, and the infinite
:loop would go away, and non-broken programs wouldn't be affected. This
:could be done for 5.30.2, I think
:
:We could make it fatal in blead.
:
:And optimizing all quantifiers of zero width assertions away or to {0,1}
:in blead would prevent things like this from happening anywhere.
If we can optimize them to a non-looping form for 5.30.2, that seems
like a fine solution - there sees no reason thereafter to make if fatal
in blead.
Hugo
Thread Previous
|
Thread Next