The blogger agrees that you should make your object's data available to the outside world in a way lets you change the underlying implemtation when you need to.

In Java, it seems like the "best practice" is to copy and paste a bunch of identical get/set methods.

The blogger seems to be against copying and pasting when native language features can give you the same benefit. With Python (apparently) you can use the built-in features to make public attributes that can be transparently upgraded from simple attributes to get/set methods, without changing the API: 

    contact.email = "x@x.com"

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Behind the scenes this can be implemented by a simple attribute variable or a get/set method. The user of the object doesn't care.

This feature isn't built in to Perl 5. If you break encapsulation and access the underlying hash keys directly: 

    $contact->{'email'} = "x@x.com";

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Then you can't protect the access without a tied hash. On the other hand, if you wrap the accessor in a method: 

    $contact->email("x@x.com");

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Then you have to copy and paste multiple identical get/set methods.

The better solution is to let a module generate the methods for you. For instance, Attribute::Property (which looks excellent, BTW - thanks for pointing it out, wolv!), automatically makes methods that are assignable like hash elements: 

    # module code
    sub email   : Property;

    # ...

    # user code
    $contact->email = "x@x.com";

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When you need to upgrade 'email' to do some validation, you can change the accessor into a full sub: 

    # module code
    sub email {
        # do some validation or processing here
    }

    # ...

    # user code - API stays the same.
    $contact->email = "x@x.com";

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Michael

In reply to Re^2: Modules for autogenerating accessor/mutator methods by magog
in thread Modules for autogenerating accessor/mutator methods by srdst13

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