in reply to Re^2: OO Pattern Container x Elements and Method Chaining
in thread OO Pattern Container x Elements and Method Chaining

Ok, but in that case, neither form - with or without the temporary variable - will achieve that. Nothing special gets communicated through method chaining. At least not in POP.

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Re^4: OO Pattern Container x Elements and Method Chaining
by LanX (Saint) on Oct 08, 2021 at 16:02 UTC
    as I said $cont->get_elem('one') can return another object belonging to a wrapper class "MemberElement" dynamically cloned from $elem0 and enriched with the container info.

    MemberElement could inherit from Element to make sure all methods are transparently available or use AUTOLOAD to delegate methods to $elem0

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery

      yes, sure, that's all cool.... but I don't believe that has any bearing on method chaining.

        For instance see https://atomicobject.com/resources/oo-programming/other-oo-class-relationships

          Association implies symmetry; both classes know each other and can message each other.

          A Product class object may need to know the last sale that it was involved with. We could put a pointer to a Sale class object inside the private part of Product.

          A Sale class object may need to know all of the Products involved with the Sale. We can put a pointer to a pointer (double pointer) in Sale that will let us store zero or more Products associated with a Sale.

        hence this is not uncommon

        $stock->product("Book")->lastSale()->undo()

        and affects both objects

        update

        a maybe better example I found is the part_of association of Apartment <-> Room

        A $room can only belong to one containing $apartment and has a (weakened) back-reference

        Like this if $room->burns() than $apartment->burns()

        > but I don't believe that has any bearing on method chaining.

        $street->apartment("5a")->room("living")->burns()

        HTH! :)

        Cheers Rolf
        (addicted to the Perl Programming Language :)
        Wikisyntax for the Monastery