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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
Re^4: A refactoring trap
by lidden (Deacon) 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.
      With this method you'll never be able to loop through the last line.
      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 ;-)

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