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RE: RE: (tye)RE: The Best Infinite Loop

by BlaisePascal (Monk)
on Oct 18, 2000 at 02:16 UTC ( #37241=note: print w/ replies, xml ) Need Help??


in reply to RE: (tye)RE: The Best Infinite Loop
in thread The Best Infinite Loop

Those three parse the same, but the block loops don't parse that way. In fact, there are at least three different ways to do an infinite loop with redo that parse differently... So I modified tye's benchmark, and got:

#!/usr/bin/perl -w use strict; use Benchmark; timethese( 1000, { '0while' => sub { $_ = 0; while (1) { $_++; last if ($_ == 10000) +; } }, '0for' => sub { $_ = 0; for (;;) { $_++; last if ($_ == 10000) +; } }, '0redo1' => sub { $_ = 0; { $_++; redo if ($_ < 10000); + } }, '0redo2' => sub { $_ = 0; { $_++; redo unless ($_ == 10000); + } }, '0redo3' => sub { $_ = 0; { $_++; last if ($_ == 10000); redo +; } }, '1while' => sub { $_ = 0; while (1) { $_++; last if ($_ == 10000) +; } }, '1for' => sub { $_ = 0; for (;;) { $_++; last if ($_ == 10000) +; } }, '1redo1' => sub { $_ = 0; { $_++; redo if ($_ < 10000); + } }, '1redo2' => sub { $_ = 0; { $_++; redo unless ($_ == 10000); + } }, '1redo3' => sub { $_ = 0; { $_++; last if ($_ == 10000); redo +; } }, }); __END__ Benchmark: timing 1000 iterations of 0for, 0redo1, 0redo2, 0redo3, 0wh +ile, 1for, 1redo1, 1redo2, 1redo3, 1while... 0for: 14 wallclock secs (11.43 usr + 0.00 sys = 11.43 CPU) 0redo1: 14 wallclock secs (11.62 usr + 0.00 sys = 11.62 CPU) 0redo2: 15 wallclock secs (12.68 usr + 0.00 sys = 12.68 CPU) 0redo3: 15 wallclock secs (12.36 usr + 0.00 sys = 12.36 CPU) 0while: 14 wallclock secs (11.48 usr + 0.00 sys = 11.48 CPU) 1for: 13 wallclock secs (11.40 usr + 0.00 sys = 11.40 CPU) 1redo1: 14 wallclock secs (11.63 usr + 0.00 sys = 11.63 CPU) 1redo2: 14 wallclock secs (11.54 usr + 0.00 sys = 11.54 CPU) 1redo3: 15 wallclock secs (12.36 usr + 0.01 sys = 12.37 CPU) 1while: 14 wallclock secs (11.42 usr + 0.00 sys = 11.42 CPU)
I don't know why the difference in times between the first run and the second...


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