This is certainly an interesting approach. "Philosophically" of the same breed as mine, IMHO, but somewhat cleaner.

Of course I would rather prefer to be able to do something just as simple as

    $rf->execute(@_) or
        $caller->complain("Error executing this and that.");
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where obviously I may not really be using all of the (unprocessed) @_, but more realistically a list prepared from @_.

my %default_bind = ( age => 23, height => 75, birthday => undef );
my @key_order = qw( age height birthday );
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Nice concept! Except that having to explicitly specify (some) keys in two places is again inelegant and error-prone. I would rather adopt some automatized mechanism along the same lines. Thanks for the input, anyway! It gave me an idea about the direction in which to proceed.