Re^2: Procedural vs OOP modules

[LanX]

> Is there any state that needs to be shared among them? If so, use OOP

Actually you can share state in the package variables, but only one set of them.

This pattern is similar to a singleton object in OOP.

(The modular interface of Data::Dumper is a good example for that, with the global config vars, like $Data::Dumper::Indent )

But you are right, a very good reason to use methods instead of functions is if they all start to look like this

package Do_Something

my %repeated = init();

foo( X, %repeated);

bar( Y, %repeated);

...

then it's obviously better to write

my $obj = Do_Something->new(%init);

$obj->foo(X);

$obj->bar(Y);

especially if there is a chance that you might need to have different initializations in the same code

my $obj2 = Do_Something->new(%other_init);

( see Data::Dumper again with it's alternative OOP interface, where the configs are encapsulated in the objects like $OBJ->Indent([NEWVAL]) or $OBJ2->Indent([NEWVAL]) )

On a side note: I prefer to think about objects like actors which do things, not containers which have attributes.

So reducing them to shared data is not the whole picture.

Last but not least: PBP lists some criteria when to use what...

[The Perlman]

For completeness: You can also share state between functions with the help of closures.

[LanX]

Actually I'd rather prefer Dumper instances implemented as closures.

The setup methods here are just constructors in disguise, no need to call them more than once.