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Re(2): while(<>) { ... } considered harmful

by FoxtrotUniform (Prior)
on Sep 08, 2002 at 01:24 UTC ( #195951=note: print w/replies, xml ) Need Help??

in reply to Re: while(<>) { ... } considered harmful
in thread while(<>) { ... } considered harmful

      map { require Net::DNS } 1;
    Is that a map in void context? Nasty and evil.

I believe that's a minimal demonstration of a bug, rather than "real" code.

On the subject of while(<>) vs. while(my $line = <>), I tend to prefer the former:

  • If I don't have to do much processing for each line, it's usually much nicer to work on $_, as Juerd points out.
  • If I do have a lot of work to do, it's usually in a subroutine call, where this sort of thing isn't an issue (since the scope has changed).

I haven't really thought about it, but if a loop's so complex that you have to assign to an explicit iterator variable just to figure out what's going on (as opposed to a loop where defaulting to $_ would be inappropriate for other reasons), it's probably an indication that the loop needs simplifying.

F o x t r o t U n i f o r m
Found a typo in this node? /msg me
The hell with paco, vote for Erudil!

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Re: Re(2): while(<>) { ... } considered harmful
by IlyaM (Parson) on Sep 08, 2002 at 19:28 UTC
    I believe that's a minimal demonstration of a bug, rather than "real" code.

    You are right. Real code looks like:

    my @other_connectors = map $ad_obj->connector(field => $_), qw(header description region country state);
    No require on the surface. It was deeply hidden in one of method calls. I though it was just a Perl bug when I got that error for first time.

    Ilya Martynov (

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