Even so, it's easier to understand than the nested-subroutines solution.

More importantly, the stackdump is more easily understood.

I wonder if anybody out there has got something even simpler.

I would hope there's something better than that. For one thing, my version doesn't allow each function to be a closure. Though, that's easy enough to fix, I suppose. 

sub localize {
    my $real = pop;

    no strict 'refs'; no warnings 'redefine';
    goto CALL unless @_;
    AGAIN: my $v = shift;
    local *{$v} = do {
        my $v2 = $v;
        sub { "changed $v2" }
    };
    goto AGAIN if @_;
    CALL: $real->();
}

[download]
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Re^3: A general method of locally overriding subroutines by dragonchild
in thread A general method of locally overriding subroutines by tmoertel

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