Perl - redo and last without a loop

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Perl - redo and last without a loop

Archive - Originally posted on "The Horse's Mouth" - 2004-12-02 08:11:43 - Graham Ellis
Perl has next, last and redo commands which (by default) cause you to move on to the next iteration / exit from / repeat the same iteration of a loop.

Did you know that you can also label a block and then use them in a similar way in that block?



$c = 1;

$d = 4;

thyme:

{

$c++;

$e = 5;

redo thyme if ($c < 3);

$f = 6;

last thyme if ($e > 3);

$g = 7;

}

$h = 8;

print ("$c $d $e $f $g $h\n");

Result:



[localhost:~/dplp] graham% perl blocker

3 4 5 6  8

[localhost:~/dplp] graham%

Note - the "redo" lets you write a loop without there being any loop word used - dangerous unless you know what you're doing and almost as frowned upon as using a goto statement (of which Perl has three flavours!). See intermediate and advanced examples.