Front page | perl.perl5.porters |
Postings from December 2009
2009/12/10 karl williamson <public@khwilliamson.com>: > demerphq wrote: >> I have two minor objections, but i dont think they need be seen as >> roadblocks. >> >> First, the problem of qr// raises its head. You construct a pattern >> one context with your new pragma in effect, and then embed it in >> another pattern somewhere else and the magicness of the pattern is >> lost. This is the same problem as with use locale, and personally >> something I think breaks the general modern model of patterns. However >> it is better than nothing and modifiers can be leveraged on top of >> your patch so that is fine IMO. > > I'm not sure I follow this. I think what you're saying is that the original > pattern is decompiled or thrown away and then recompiled under the new > scheme? Yes. Essentially that is how embedding a qr// object into another pattern works. Basically its like a C include. When you do: my $qr1= qr/this is a pattern/; my $qr2= qr/this is a pattern containing another pattern $qr1/; the *source* of $qr1 is embedded in $qr2, not the opcodes. So any behaviour that is controlled that by pragmatta and not by in-regex modifiers will be lost. This is why the /msix modifiers have (?msix: ... ) forms. >> >> Second, and really this is just another facet of the original problem >> is that people now need to modify existing code to preserve the >> existing semantics. If this was controlled by modifier then this >> wouldnt be necessary as we would just make the default modifier behave >> as in 5.8.x, also if really necessary we could bifurcate the POSIX >> stuff into multiple opcodes (old/new behaviour) and resolve any >> objections to fixing the POSIX opcodes. > > One should be able to change the default modifier, I would hope. Yes, i was thinking that a good plan would be to just define a generic interface for specifying default modifiers. The people that like to follow PBP recommendation of using /msx always can use the pragma. Yves -- perl -Mre=debug -e "/just|another|perl|hacker/"Thread Previous | Thread Next