Front page | perl.perl5.porters |
Postings from February 2009
2009/2/10 Zefram <zefram@fysh.org>: > Secondarily, perl ought to pay attention to (?>...), to avoid generating > backtracking records that it can never use. Im doubtful this will happen. You see, (?>...) turns into two regops, that bracket a set of other regops. These regops push records onto the stack. If we were to check to see if we were "inside" of the regops that bracket the expression we would pay a price for every regop, regardless if they used the (?>...) construct, which isnt really used that often. So instead we just let them accumulate information in the stack, and then throw it all away when we hit the closing regop. Its not perfect but it lets the people that use the construct pay the price. I guess we could bifurcate all the regops, but that gets messy. What id rather see happen is that perl does on the fly DFA construction when it makes sense to do so. The effect would be the same, but we would have a generic solution to a whole class of problems and not a special case for every regop based on a special regex construct. cheers, Yves -- perl -Mre=debug -e "/just|another|perl|hacker/"Thread Previous | Thread Next