note
adrianh
<p>++ Nice summary.</p>
<p>Minor niggle. If it were me I would put a little bit more emphasis on lexical scoping and a little less emphasis on reference counting. When the value of a lexical variable is garbage collected is independent of whether a Perl closure is created. It's about scope - not memory usage. For example:</p>
<code>
our $Global;
sub make_closure {
my %lexical;
$Global = \%lexical;
return sub {
my $key = shift;
@_ ? $lexical{$key} = shift : $lexical{$key};
};
};
{
# here we make a closure
my $c = make_closure();
# which we can use to set and get keys
$c->(foo => 42);
print "foo is ", $c->('foo'), "\n";
# at the end of the scope the closure goes away
};
# but the referant is still around
print "Global foo is ", $Global->{foo}, "\n";
</code>
<hr>
<p>Update: It might also be worth comparing what Perl does to languages without lexical capture like C.</p>
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