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Re: Unset array doesn't work
From: |
Chet Ramey |
Subject: |
Re: Unset array doesn't work |
Date: |
Tue, 27 Feb 2018 11:18:40 -0500 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 |
On 2/26/18 4:31 AM, Robert Elz wrote:
> Date: Mon, 12 Feb 2018 09:26:37 -0500
> From: Chet Ramey <chet.ramey@case.edu>
> Message-ID: <790ade74-690f-541c-9ab4-6359917442d0@case.edu>
>
> | This is bash's dynamic scoping. The visibility of a local variable is
> | restricted to a function and its children, and `unset' removes the
> | currently-visible instance. Removing such an instance can `unconver' an
> | instance in a previous scope.
>
> Frankly this is brain dead, unset should not be unlocal (or something equiv)
>
> eg: if I have a func
>
> myfunc() {
> local IFS
> unset IFS
> # do some code
> }
>
> the very last thing that I want is for the global IFS to apply.
It doesn't. Run the following script:
func()
{
local var=$'a\tb\tc'
typeset IFS=' '
echo ${FUNCNAME}: before unset: $var
unset IFS
echo ${IFS:-null or unset}
echo ${FUNCNAME}: after unset: $var
}
IFS='%'
declare -p IFS
func
declare -p IFS
You'll see that the first expansion of `$var' uses the local value of IFS,
the second expansion uses the default value of $' \t\n', and the global
value doesn't change (or get unset) outside the function.
The objection was that the global or previous-scope value didn't get unset
when using the `unset' builtin; only in the local scope was it unset.
--
``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/
- Re: Unset array doesn't work, (continued)
- Re: Unset array doesn't work, Nikolai Kondrashov, 2018/02/12
- Re: Unset array doesn't work, Robert Elz, 2018/02/26
- Re: Unset array doesn't work, Clint Hepner, 2018/02/26
- Re: Unset array doesn't work, Greg Wooledge, 2018/02/26
- Re: Unset array doesn't work, Clark Wang, 2018/02/26
- Re: Unset array doesn't work, Robert Elz, 2018/02/26
- Re: Unset array doesn't work, Chet Ramey, 2018/02/27
- Re: Unset array doesn't work, Robert Elz, 2018/02/26
- Re: Unset array doesn't work, Chet Ramey, 2018/02/27
- Re: Unset array doesn't work, Chet Ramey, 2018/02/27
- Re: Unset array doesn't work,
Chet Ramey <=
- Re: Unset array doesn't work, Robert Elz, 2018/02/27
- Re: Unset array doesn't work, Chet Ramey, 2018/02/28
- Re: Unset array doesn't work, Robert Elz, 2018/02/28
- Re: Unset array doesn't work, Greg Wooledge, 2018/02/28
- Re: Unset array doesn't work, Chet Ramey, 2018/02/28
- Re: Unset array doesn't work, don fong, 2018/02/28
- Re: Unset array doesn't work, Robert Elz, 2018/02/28