New Features of Perl 5.14: IO::File on Demand

May 24, 2011 by chromatic

Perl 5.14 is now available. While this latest major release of Perl 5 brings with it many bugfixes, updates to the core libraries, and the usual performance improvements, it also includes a few nice new features.

One such feature is loading IO::File on demand.

Autovivification of filehandles (colloquially known as “lexical filehandles”) has been in Perl 5 since the release of Perl 5.6.0:

    open my $fh, '>', $filename
        or die "Cannot write to '$filename': $!\n";

These filehandles behaved something like objects if you loaded IO::File or IO::Handle, in that you could call methods on them:

    use IO::File;
    $fh->autoflush(1);

Even though the Perl 5 core performed the appropriate gyrations to produce these filehandles associated with the proper class, you had to remember to use the appropriate module manually.

Perl 5.14 now requires IO::File if necessary for you. This is a small feature, but it smooths out a confusing wrinkle in an important feature of modern Perl 5.