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Postings from February 2020
On 2/13/20 8:11 PM, hv@crypt.org wrote: > 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. > > Hugo > Thanks for digging Done in https://git.io/JvlRe, though I'm not sure whether the comments I changed add any value.Thread Previous | Thread Next