Re^5: closure clarity, please

[vitoco]

in reply to Re^4: closure clarity, please
in thread closure clarity, please

Impressive! I could follow you step by step. After a second read (starting from the last step), I realized how the interpreter seems to work.

I think that I could simplify your work by excluding the "outer f" subroutine from the improved example, but as it is, is a great pedagogical example and explanation.

Thank you very much! And more thanks goes to ikegami.

BTW, this is not the way I program. I just wanted to understand what the OP was trying to explain. Everyday I learn something new of Perl's world. I'm not sure if I'm ready for Perl 6.

[JadeNB]

Here's another way of demonstrating the effect in your sample code, with hopefully a bit less “magic gluing”:

sub g {
    my ( $a ) = @_;
    sub f { $a };
    return sub { $a = $_[0] };
}

push my @setters, g("Hi\n"), g("Bye\n");

print f; # => Hi
$setters[0]("Bye\n");
print f; # => Bye
$setters[1]("Hi\n");
print f; # => Bye (still)