sub xarg       { my $tmp = $_[0]; length $tmp }
sub xarg_shift { my $tmp = shift; length $tmp }

##</code><code>##

Benchmark: running arg, arg_shift, noarg, noarg2, xarg, xarg_shift for at least 10 CPU seconds...
       arg: 10 wallclock secs (10.52 usr + -0.01 sys = 10.51 CPU) @ 489653.09/s (n=5146254)
 arg_shift: 10 wallclock secs (10.28 usr +  0.00 sys = 10.28 CPU) @ 414663.33/s (n=4262739)
     noarg:  9 wallclock secs (10.00 usr +  0.00 sys = 10.00 CPU) @ 287455.40/s (n=2874554)
    noarg2: 11 wallclock secs (10.55 usr +  0.00 sys = 10.55 CPU) @ 282535.73/s (n=2980752)
      xarg: 10 wallclock secs (10.59 usr +  0.00 sys = 10.59 CPU) @ 337761.28/s (n=3576892)
xarg_shift: 10 wallclock secs (10.39 usr +  0.01 sys = 10.40 CPU) @ 297917.40/s (n=3098341)
               Rate    noarg2     noarg xarg_shift      xarg arg_shift       arg
noarg2     282536/s        --       -2%        -5%      -16%      -32%      -42%
noarg      287455/s        2%        --        -4%      -15%      -31%      -41%
xarg_shift 297917/s        5%        4%         --      -12%      -28%      -39%
xarg       337761/s       20%       18%        13%        --      -19%      -31%
arg_shift  414663/s       47%       44%        39%       23%        --      -15%
arg        489653/s       73%       70%        64%       45%       18%        --

##</code><code>##

$"=$,,$_=q>|\p4<6 8p<M/_|<('=>
.q>.<4-KI<l|2$<6%s!<qn#F<>;$,
.=pack'N*',"@{[unpack'C*',$_]
}"for split/</;$_=$,,y[A-Z a-z]
         {}cd;print lc