Re: Exiting eval via next: is that so bad?

in reply to Exiting eval via next: is that so bad?

Well, you should be aware of the fact that the next from within the eval jumps to the end of an enclosing loop, which might be a little bit surprising. Example:

my $var = 5;
{
  eval {$var = 3; next};
  $var = 4;
}
print $var; # 3 !!
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The block after eval does not count as a loop block (same as do), so the loop commands next, redo and last work on the outer block. To make the eval block a loop block (so that you can redo it e.g.) double the braces like this:

eval {{
  $i++;
  redo unless do_sth($i);
}}
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-- Hofmator

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Re^2: Exiting eval via next: is that so bad? by dd-b (Monk) on Sep 23, 2011 at 19:36 UTC
Please forgive necromancy. In the case I just hit, I'm doing this: `CLIENT: while (!exitflag) { eval { # Various things that might throw exceptions if (blah blah) { next CLIENT; } }; if ($@) { # Exception handling } }` [download] So, I'm not just exiting the eval, I'm exiting considerably more. AND I'm doing it by an explicit label, not implicitly, so I really shouldn't be confused about what I'm doing. I'd really prefer not to get this warning in the case when I'm using a loop label to exit a particular loop. (The big while loop is handling client connects as they come in, the eval inside it is to prevent unexpected errors from killing the whole server; they just abort the one connection. This is test code, the full version will fork of course, once it can handle the simple case.)	[reply] [d/l]
Re^3: Exiting eval via next: is that so bad? by Anonymous Monk on Sep 24, 2011 at 02:01 UTC
Please forgive necromancy. Hi New questions go in Seekers Of Perl Wisdom Welcome You might wish to review The Perl Monks Guide to the Monastery, How do I post a question effectively?, Where should I post X? $ perl -wle " 0+$foo; LABEL: for(1,2){ eval { next LABEL; }; }" Useless use of addition (+) in void context at -e line 1. Name "main::foo" used only once: possible typo at -e line 1. Use of uninitialized value $foo in addition (+) at -e line 1. Exiting eval via next at -e line 1. Exiting eval via next at -e line 1. $ perl -wle " no warnings q[exiting]; 0+$foo; LABEL: for(1,2){ eval { + next LABEL; }; }" Useless use of addition (+) in void context at -e line 1. Name "main::foo" used only once: possible typo at -e line 1. Use of uninitialized value $foo in addition (+) at -e line 1. [download] Related discussions Exiting subroutine via next, #29238: exiting eval via last	[reply] [d/l]
Re^4: Exiting eval via next: is that so bad? by dd-b (Monk) on Oct 17, 2011 at 20:48 UTC
In my mind, this wasn't a new question, it was a continuation of a discussion I'd found. Isn't the idea of searching first to avoid starting new questions when reasonably possible? Anyway, thanks for your suggestion of the "no warnings" pragma.	[reply]
Re^5: Exiting eval via next: is that so bad? by Anonymous Monk on Oct 18, 2011 at 11:00 UTC
Re^5: Exiting eval via next: is that so bad? by jdporter (Paladin) on May 05, 2012 at 01:25 UTC
Re^6: Exiting eval via next: is that so bad? by Anonymous Monk on May 05, 2012 at 08:10 UTC

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