Re: "local -g" declaration references local var in enclosing scope

[Chet Ramey]

On 3/11/24 12:08 AM, Kerin Millar wrote:

> Speaking of which, to do both of these things has some interesting effects ...
>
> $ z() { local -g a; unset -v a; a=123; echo "innermost: $a"; }; unset -v a; x; 
> declare -p a
> innermost: 123
> inner: 123
> outer: 123
> declare -- a
>
> $ z() { local -g a; unset -v a; unset -v a; a=123; echo "innermost: $a"; }; 
> unset -v a; x; declare -p a
> innermost: 123
> inner: 123
> outer: 123
> declare -- a="123"

These show the normal effects of unset combined with dynamic scoping. This
ability to unset local variables in previous function scopes has been the
subject of, um, spirited discussion.

> $ x() { local a; y; local +g a; a=456; echo "outer: $a"; }; unset -v a; x; 
> declare -p a
> innermost: 123
> inner: 123
> outer: 456
> declare -- a="123"

Let's assume the previous function definitions remain in effect here. In
that case, z continues to unset the local variable definitions in previous
scopes, but the `local +g a' is basically a no-op -- it implies not using
the global scope for a, which is the same as not using the option at all.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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