Re: "unset var" pops var off variable stack instead of unsetting it

[Peter & Kelly Passchier]

On 20/03/2560 04:51, Stephane Chazelas wrote:
> On comp.unix.shell ot http://unix.stackexchange.com, I've posted
> many articles describing how to do splitting in POSIX-like
> shells:
> 
> ( # subshell for local scope
>   unset -v  IFS # restore default splitting behaviour
>   set -o noglob # disable globbing
>   cmd -- $var   # split+glob with default IFS and glob disabled
> )
> 
> I'm now considering adding a note along the lines of:
> 
>   "Beware that with current versions of bash, pdksh and yash,
>   the above may not work if used in scripts that otherwise use
>   typeset/declare/local on $IFS or call a function with
>   `IFS=... my-function' (or IFS=... eval... or IFS=...
>   source...)"
> 

Wouldn't it be better to avoid using a function like 'unset' (that works
in the way you purport to expect) in a dynamically scoped language as a
matter of principle?? If unset works like you would want/expect it, it
would also discard all values of all higher scopes. Would it not be
better to set IFS to the value desired (whatever default splitting
behaviour you need)??

-- 
Peter