Beefy Boxes and Bandwidth Generously Provided by pair Networks
"be consistent"
 
PerlMonks  

Re^2: A refactoring trap

by ihb (Deacon)
on Aug 23, 2005 at 21:47 UTC ( [id://486026] : note . print w/replies, xml ) Need Help??


in reply to Re: A refactoring trap
in thread A refactoring trap

Dispite that many has pointed out that

while (my $line = <DATA>) { ... } while (defined (my $line = <DATA>)) { ... }
are identical, your first remark is true. The problem lies elsewhere:
while (<DATA>) { ... }
doesn't localize $_ and thus leaves $_ undefined after the loop.
while (my $line = <DATA>) { ... }
doesn't suffer from this as it doesn't touch $_.

If put in a subroutine this innocent little bug cause a serious headache while trying to find out why $_ all of a sudden is undefined.

ihb

See perltoc if you don't know which perldoc to read!