APM: regularni vyrazy

[Jenda Krynicky]

Zkousel jsem si benchmarknout jestli Perl je dostatecne intelignetni 
aby dokazal optimalizovat regularni vyrazy jak jsme se o tom vcera 
bavili. Neni. Ale mezi [cdefgh] a (?:c|d|e|f|g|h) uz moc rozdil neni.

	use Benchmark;
	
	my @s = ("aaaa" .. "bbbb");
	
	sub Group {
		my $res = 0;
		for (@s) {
			/ab[cdefgh]/ and $res++;
		}
		return $res;
	}
	
	sub ORs {
		my $res = 0;
		for (@s) {
			/abc|abd|abe|abf|abg|abh/ and $res++;
		}
		return $res;
	}
	
	sub SmallORs {
		my $res = 0;
		for (@s) {
			/ab(?:c|d|e|f|g|h)/ and $res++;
		}
		return $res;
	}
	
	timethese 500, {
		Group => \&Group,
		ORs => \&ORs,
		SmallORs => \&SmallORs,
	}


Perl v5.6.1 built for MSWin32-x86-multi-thread
Benchmark: timing 500 iterations of Group, ORs, SmallORs...
     Group:  9 wallclock secs ( 9.05 usr +  0.00 sys =  9.05 CPU) 
		@ 55.23/s (n=500)
       ORs: 30 wallclock secs (27.72 usr +  0.01 sys = 27.73 CPU) 
		@ 18.03/s (n=500)
  SmallORs: 10 wallclock secs ( 9.18 usr +  0.01 sys =  9.19 CPU) 
		@ 54.39/s (n=500)


Perl 5.8 RC2 ( v5.7.3 built for MSWin32-x86-multi-thread) dava 
prakticky stejne vysledky:

Benchmark: timing 500 iterations of Group, ORs, SmallORs...
     Group: 12 wallclock secs (11.55 usr +  0.01 sys = 11.56 CPU) 
		@ 43.26/s (n=500)
       ORs: 33 wallclock secs (31.02 usr +  0.04 sys = 31.06 CPU) 
		@ 16.10/s (n=500)
  SmallORs: 13 wallclock secs (11.62 usr +  0.01 sys = 11.63 CPU) 
		@ 43.00/s (n=500)


Jenda

=========== Jenda at Krynicky.cz == http://Jenda.Krynicky.cz ==========
There is a reason for living. There must be. I've seen it somewhere.
It's just that in the mess on my table ... and in my brain
I can't find it.
					--- me

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