Re: Changing the way bash expands associative array subscripts

[Chet Ramey]

On 4/6/21 10:28 AM, Koichi Murase wrote:

> Thank you for the pointer. I still think changing the syntactic
> treatment of the arguments of the `unset' builtin is the cleanest way
> to solve the problem of `key=@; unset -v a[$key]'. Maybe we can ask
> Chet why this isn't considered. 

It's not necessary, and the cost and resultant mess aren't worth it.

> We now see two benefits of changing
> the treatment of the arguments of `unset', 1) `unset -v a[$key]' is
> not the subject to the pathname expansions and word splitting. 

Appropriate quoting.

> 2) we
> can distinguish the erasure of the element associated with key=@
> `unset -v a[$key]' from the entire array erasure `unset -v a[@]'. 

I'm prepared to accept the argument that it's not necessary to support
a[@] unsetting the entire array except in a compatibility mode.

> Conversely, there are definitely more codes naively writing as `unset
> a[1]' which can be broken by pathname expansions. 

I don't think the way to fix broken code is to change the shell to
accommodate it. The bash documentation has warned about this for a long
time.

--
``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/