Suppose you have a method of a class that you write using Moose(but a plain Perl object is also relevant), and you use inside that method a static variable (static in the C sense, by that I mean a variable that has scope local to the method but a lifetime that spans each call of said method). I was recommended that I use a closure and enclose the declaration of that variable and the method inside the closure to cause the variable to be static(again, the C sense of static).

Mixing C-think and Perl-think is not always a good idea. What you are looking for is a state variable, and that is a feature that is new with 5.10 and has to be requested. No closure is required.

Pre-5.10 you do this with a closure. 

{ # open an anonymous block to form the closure

    my $foo;
    my $bar;

    sub fubar {
       # code that uses $foo and $bar
       # goes in here
   }

} # end of the closure

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At the end of the closure the two variables go out of scope, but subsequent calls to fubar() still can use them without a problem.

- doug

In reply to Re: Some trouble with closures by doug
in thread Some trouble with closures by spx2

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