Labels at beginning of a block

apomatix has asked for the wisdom of the Perl Monks concerning the following question:

This code causes a syntax error:

#!/usr/bin/perl
use strict;
grep {
 NUM:
  for(0 .. $_)  {
    last NUM if $_ > 3;
  }
}  1 .. 10;
[download]

syntax error at ./test.pl line 4, near "NUM:"
syntax error at ./test.pl line 8, near "}"
Execution of ./test.pl aborted due to compilation errors.
[download]

One fix is to put something in front of the label:

#!/usr/bin/perl
use strict;
grep {
  1;
 NUM:
  for(0 .. $_)  {
    last NUM if $_ > 3;
  }
}  1 .. 10;
[download]

Is there any way to start the block with a label?

Comment on Labels at beginning of a block Select or Download Code

Replies are listed 'Best First'.
Re: Labels at beginning of a block by jwkrahn (Abbot) on Aug 19, 2011 at 19:56 UTC
The label goes before the block, which you can't do with a grep (or map) block, and besides, you are using grep in void context which makes no sense in your example. You probably need something like this: `NUM: for my $i ( 1 .. 10 ) { for ( 0 .. $i ) { last NUM if $_ > 3; } }` [download]	[reply] [d/l]
Re: Labels at beginning of a block by Anonymous Monk on Aug 20, 2011 at 03:03 UTC
perl v5.14.1 has no problem with the syntax	[reply]