Re^2: Lost anonymous subs

I have written almost exactly the same piece of code in the reply to diotalevi up there because did not spot your comment. Yes, that helped me to understand things.

I somehow got thinking that closures copy referenced lexicals when created. That was my error.

This is the case when copying really takes place:

my $Big = 'X' x 1000000;
sub big {
    my $big = $Big;
    return sub { $big };
}
my @crefs;
push @crefs, big() for 1..10;
[download]

--kap

Comment on Re^2: Lost anonymous subs Download Code

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Re^3: Lost anonymous subs by diotalevi (Canon) on Dec 09, 2004 at 17:21 UTC
Well yes, that's because the = operator copies stuff. There's nothing special about that.	[reply]
Re^4: Lost anonymous subs by kappa (Chaplain) on Dec 10, 2004 at 12:07 UTC
`my @abc; for my $m qw/a b c/ { push @abc, sub { $m }; } print $_->() . "\n" for @abc;` [download] No assignments and still, those subs each has its own `$m`. Or does the `for my $m` creates a new variable on each iteration? --kap	[reply] [d/l] [select]
Re^5: Lost anonymous subs by diotalevi (Canon) on Dec 10, 2004 at 15:02 UTC
The my() operator has a runtime effect of creating a new variable so each time you start that loop, you have a new variable to have potentially bound to. This also works if you write code like this. `my @abc; for my $m ( qw/a b c/ ) { push @abc, \ $m; } print @abc` [download]	[reply] [d/l]
Re^6: Lost anonymous subs by kappa (Chaplain) on Dec 10, 2004 at 15:27 UTC
Re^7: Lost anonymous subs by diotalevi (Canon) on Dec 10, 2004 at 16:20 UTC
Some notes below your chosen depth have not been shown here
Re^3: Lost anonymous subs by ysth (Canon) on Dec 10, 2004 at 11:50 UTC
Not exactly copy, more just steal. Usually lexicals hang around for the next time they go into scope (though they get reset to be empty/undef, they still hold memory). If you take a reference to one (including the case of a closure) and hold the reference until the lexical goes out of scope, the lexical has to get reallocated, since the remaining reference keeps the original.	[reply]