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Postings from February 2020
Earlier I wrote: :Karl Williamson <public@khwilliamson.com> wrote: ::I have been looking at the code in regcomp.c in regpiece() that deals ::with quantifiers. [...] ::Two of the flags WORST and SPSTART do not appear to ever be looked ::at. Should we remove them, or dig to find out how they used to be used, ::or might they come back again, and we should set them consistently? : :I definitely think there's value in some digging, I'm happy to give that :a go, time permitting. But of those I'm sure at least WORST would be :from Ilya, quite likely SPSTART too, so digging is not guaranteed to :lead to light. That didn't take long. SPSTART does not appear ever to have been used for anything - looks like it was introduced in perl-3, propagated with some new features in perl-4, and never touched thereafter. WORST is slightly different: it is defined as 0, so represents the state where all the other flags (representing something we know) are disabled. I don't know why it is included in: *flagp = (op != '+') ? (WORST|SPSTART|HASWIDTH) : (WORST|HASWIDTH); .. but that also appears to have been in from the start. So I think SPSTART can go, WORST is probably best replaced with a literal zero in the three other places it is used, with a change of comment - the word "worst" is now misleading, since the flags no longer only represent things that permit more powerful optimizations. HugoThread Previous | Thread Next