Re4: Finding part of a file

That code produces the warning:

Exiting eval via last at line 8, <DATA> line 5.
[download]

when warnings are turned on.... I'm not entirely sure why 'last'ing out of an eval block is bad, but I do know that eval is overkill for what you've written. do is probably more appropriate. The following code issues no warnings:

#!/usr/bin/perl -wT
use strict;

my $begin='banana';
my $end='grape';

while(<DATA>) {
  /^$begin$/ && do { /^$end$/ ? last : print while (<DATA>) }
}

__DATA__
apple
banana
pear
peach
grape
orange
[download]

Update: You might want to replace the last above with a next if you want multiple windows to print... For instance, it changes what gets printed using this data:

__DATA__
banana
pear
peach
grape
orange
banana
cow
pig
grape
[download]

Notice that 'cow' and 'pig' are between a second set of on/off toggles... last will skip them next will print them. Which is the desired behavior? Your guess is as good as mine.

-Blake

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Re: Re4: Finding part of a file by belden (Friar) on Dec 05, 2001 at 22:54 UTC
Yep, there's a reason I didn't include warnings in my code snippet :) Going to have to read up on eval vs die and figure out why eval is overkill in this case... Interestingly enough, I can goto outside of an eval block without any complaints: `#!/usr/bin/perl use strict; use warnings; my $begin='banana'; my $end='grape'; while(<DATA>) { /$begin/ ? eval { /$end/ ? goto END : print while (<DATA>) } : next } END: exit; __DATA__ apple banana pear peach grape orange` [download] ...re your update - that's a neat trick that I'll have to tuck away. blyman	[reply] [d/l]

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Re: Re4: Finding part of a file
by belden (Friar) on Dec 05, 2001 at 22:54 UTC

eval is overkill

Interestingly enough, I can goto outside of an eval block without any complaints:

#!/usr/bin/perl

use strict;
use warnings;

my $begin='banana';
my $end='grape';

while(<DATA>) {
  /$begin/ ? eval { /$end/ ? goto END : print while (<DATA>) }
           : next
}

END:
exit;

__DATA__
apple
banana
pear
peach
grape
orange
[download]

blyman

[reply]
[d/l]