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Re^2: Closure Explanation

by runrig (Abbot)
on Apr 30, 2010 at 20:37 UTC ( #837846=note: print w/ replies, xml ) Need Help??

in reply to Re: Closure Explanation
in thread Closure Explanation

Closure example:

sub rtn_closure { my $i = shift; return sub { $i++ }; } # f's i starts at 5 my $f = rtn_closure(5); print $f->(),"\n"; # Prints 5 print $f->(), "\n"; # Prints 6 # g gets a separate i that starts at 10 my $g = rtn_closure(10); print $g->(), "\n"; # Prints 10 print $g->(), "\n"; # Prints 11 print $f->(), "\n"; # Prints 7
Callback example:
sub exec_callback { my $f = shift; $f->(); } exec_callback(sub {print "hello\n"});
Does that help? A callback does not have to close over any variables, although it could. A closure occurs whenever a function refers to a variable in an outer scope.

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