"Christopher J Bottaro" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > hey, > i'm a c/c++ programmer struggling to pick up OO perl. i've been reading the > perltoot and i have question about the following: > > package Person; > use strict; > > sub new { > my $self = {}; > $self->{NAME} = undef; > $self->{AGE} = undef; > $self->{PEERS} = []; > bless($self); # but see below > return $self; > } > > sub name { > my $self = shift; > if (@_) { $self->{NAME} = shift } > return $self->{NAME}; > } > > ok, in the sub new(), i understand that $self is a ref and new() is returning > it. what does bless do (the single arg version). i thought bless takes 2 > args: what to bless and the name to bless it with...? what else does bless > do besides give something a type?
It marks the referent in the symbol table that $self refers to so that the referent knows its associated with a class. > in the sub name(), what is the first argument? obviously its a reference to a > person object (or whatever new() returned). but why? i've written subs > before and used shift(), but this is confusing me. say i have $person = > Person->new(); now i do $person->name(); i'm not passing it any arguments > so why is the sub name() receiving an argument which is a reference to a > Person object? does it have something to do with bless()? something to do > with being a part of package? $person->name(); does pass an argument to name(), a reference to a hash that refers to the same hash $person does. Think about this: my($frank) = Person->new(); # class method -- $_[0] eq 'Person'; my($jimmy) = Person::new(); # plain 'ol function call -- $_[0] eq ''; my($mike) = $jimmy->new(); # object method -- $_[0] eq 'HASH(0x1abf0e0)'; Todd W. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
