Re: closures: anonymous subs vs function templates?


Perl-Sensitive Sunglasses
	PerlMonks

Re: closures: anonymous subs vs function templates?

by Anonymous Monk

on Dec 21, 2014 at 09:53 UTC ( [id://1110943]=note: print w/replies, xml )

Need Help??

in reply to closures: anonymous subs vs function templates?

What is a 'function template?' local *name = sub {}; versus my $name = sub {}; are both created using anonymous subs. The assignment operator makes them go to different places though (sym table and lexpad, resp.). Then the difference between them is the same as the difference between all other local/my variables...

use 5.020;
use warnings;

outer1();

exit 0;

sub outer1 {
    my $hello = 'hello';

    local *inner = sub {
        say $hello;
    };
    outer2();
}

sub outer2 {
    inner();
}

__END__
hello
[download]

Comment on Re: closures: anonymous subs vs function templates? Select or Download Code

Replies are listed 'Best First'.

Re^2: closures: anonymous subs vs function templates?
by 5haun (Scribe) on Dec 21, 2014 at 13:02 UTC

Thank you for that example. When edited as shown below, it clearly highlighted the differences:

use warnings;
use v5.14;

outer1();

exit 0;

sub outer1 {
    my $hello = 'hello';

    # local *inner = sub {
    my $inner = sub {
        say $hello;
    };
    outer2();
}

sub outer2 {
    # inner();
    $inner->();
}

__END__
Global symbol "$inner" requires explicit package name at /tmp/subtst.p
+l line 20.
Execution of /tmp/subtst.pl aborted due to compilation errors.
[download]

Compared with your example, we can show the more limited scope of the lexical form, as recommended by Laurent_R. Thank you both!

[reply]
[d/l]

In Section Seekers of Perl Wisdom