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When to bless a Perl variable

Archive - Originally posted on "The Horse's Mouth" - 2005-03-15 19:52:55 - Graham Ellis

Perl's bless function, which turns a reference into an instance of an object, it typically called up as the last action in a constructor method. On today's Perl for Larger Projects course, I was challenged as to when else it might be used. Here's an example - when loading a file of information into objects, in a method that's returning a whole list of objects:



sub fileload {

        my ($class,$fname) = @_;

        open (FH,$fname);

        my @result;

        while (<FH>) {

                my ($thisclass,$breed,$age,$equiv) = split;

                my %self;

                $self{breed} = $breed;

                $self{age} = $age;

                $self{equiv} = $equiv;

                push @result, bless \%self,$thisclass;

                }

        return @result;

        }


Interesting, this code's also an example of the two parameter use of bless, where an object is being blessed into a class that's not got the same name as the current package.