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Re^3: A refactoring trap

by redlemon (Hermit)
on Aug 17, 2005 at 08:14 UTC ( #484338=note: print w/ replies, xml ) Need Help??


in reply to Re^2: A refactoring trap
in thread A refactoring trap

Hmmm, you're right. It doesn't break.

The reason is that blank lines are not truely blank, of course. You're saved by the fact that a blank line still contains the "\n".

--
Lyon


Comment on Re^3: A refactoring trap
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Re^4: A refactoring trap
by lidden (Curate) on Aug 17, 2005 at 09:53 UTC
    No it still works with chomp:
    while(chomp (my $line = <DATA>)){
    At least with newer perl versions. Tried with perl5.8.6.
      No it still works with chomp

      To understand why this works, take a look at the return value for chomp. Hint: it's not the string with newlines missing.

      The problem with while (my $line = <DATA>) {} is real, it's just obscure. As hinted, it only happens when you get a line with a false value and no newline. Sometimes this happens at the end of a file. Sometimes it happens for other reasons. It usually doesn't cause any actual problems, but certainly is something to look out for.

        The problem with while (my $line = <DATA>) {} is real, it's just obscure

        ARRRRGH! :-)

        As has already been pointed out this hasn't been a problem for some time. Perl automatically adds the defined for you, as you can easily see by running:

        a% perl -MO=Deparse -e 'while (my $line = <DATA>) {}' while (defined(my $line = <DATA>)) { (); } __DATA__ -e syntax OK

        This hasn't been a problem for Perl for quite some time, and I wish people wouldn't keep saying it is ;-)

      With this method you'll never be able to loop through the last line.

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