If you want to use the same transliteration more than once, you could try evalling it to a sub like this: 

my $tr = "/a-z/n-za-m/"; my $trs = eval qq{sub {\$_[0]=~tr$tr}}; 
$s = "uryyb, jbeyq\n"; &$trs($s); print $s;

[download]
This way, you can use the same transliteration any number of times and compile it only once.

You can even cache multiple tr patterns like this: 

{ my %trd; sub trd { my $tr = $_[0]; $trd{$tr} ||= do { warn "compilin
+g tr$tr"; eval qq{sub {\$_[0]=~tr$tr}} }; } } 
$t = $s = "hello, world\n"; &{trd("/a-z/n-za-m/")}($s); print $s; &{tr
+d("/a-z/A-Z/")}($t); print $t; &{trd("/a-z/n-za-m/")}($s); print $s;

[download]

Update: If you want to compile translation tables only once, I can ask, can't I compile a printf/scanf pattern, or a pack/unpack pattern once? I don't think creating a translation table would be so slow. One would have to benchmark it to say anything of course.

In reply to Re: efficient string translation? by ambrus
in thread efficient string translation? by 5mi11er

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