The arrow operator always operates on the value to its left. That means that your second example would be equivalent to this:
my $result1 = $Person->name('Homer');
my $result2 = $result1->job('safety inspector');
my $result3 = $result2->wife('Marge');
$result3->fav_food('Duff');
where the result variables are temporary. In order for the code to work as expected, the methods (name, job, wife, fav_food) must return the original object. A sample method that works this way would look like this (assuming the object is a hash ref):
sub name {
my ($self, $value) = @_;
if (defined $value) { # if a value is given
$self->{name} = $value; # set the value
return $self; # return the original object
}
return $self->{name}; # else return the name
}
This code fragment will set the value and return the object if a value is given, else it will return what the name is set as.
So why do you sometimes see the original object ($Person in this case) have multiple method calls originating from the original obect on multiple lines? Because if the method returns a value other than itself (which is quite common), it will try to call the method on that value, and most likely fail.
elusion : http://matt.diephouse.com
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