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Postings from January 2022
On Tue, Jan 25, 2022 at 02:37:19PM +0000, hv@crypt.org wrote:
> In this case, it's an inline recursive function of which the relevant
> parts look a bit like:
>
> sub do_stuff {
> my $prod = 1;
> my $recurse;
> $recurse = sub {
> ...
> for my $new (@interesting_values) {
> local $prod = $prod * $new; # aspirational
> $recurse->();
> }
> };
> $recurse->();
> }
>
> .. so shadowing doesn't help. Alternatives such as a) making it a
> one-element array, b) passing it as an argument or c) manually
> saving and restoring are all possible, but all likely to be slower,
> more error-prone, and add complexity to already-complex code.
>
> The real code's aim is to find new values for https://oeis.org/A292580.
> It's very much a work-in-progress, but if you're interested look at
> https://github.com/hvds/seq/blob/master/divrep/oul#L167 for current
> implementation (as one-element array).
>
> Hugo
Though personally I would agree with demerphq to just use a localized
global, I think one way around this to get what you want is to write:
my $h = {prod => 1};
...
$recurse = sub {
...
local $h->{prod} = $h->{prod} * $new;
...
};
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