On Tue, Nov 19, 2024 at 01:40:12AM -0500, Harry Clauson wrote:
> URL:
> <https://savannah.gnu.org/bugs/?66460>
>
> Summary: A documentation correction regarding an array
> nameref???
> Group: The GNU Bourne-Again SHell
> Submitter: harryc
> Submitted: Tue 19 Nov 2024 06:40:06 AM UTC
> Category: None
> Severity: 3 - Normal
> Item Group: None
> Status: None
> Privacy: Public
> Assigned to: None
> Open/Closed: Open
> Discussion Lock: Any
>
>
> _______________________________________________________
>
> Follow-up Comments:
>
>
> -------------------------------------------------------
> Date: Tue 19 Nov 2024 06:40:06 AM UTC By: Harry Clauson <harryc>
> I was surprised that the documentation for "declare -n" states:
>
> "The nameref attribute cannot be applied to array variables."
>
> This appears to be incorrect as I frequently pass arrays using a nameref to
> avoid the overhead of making a copy of large amounts of data.
>
> For example:
>
> ####################################################
> function doit {
> local -n blahref=$1
> echo ${blahref[2]} # displays z
> blahref[2]=a
> blahref[3]=b
> return 0
> }
>
> declare -a blah
> blah=(x y z)
>
> echo ${blah[2]} # displays z
>
> doit blah
> echo ${blah[2]} # displays a
> echo ${blah[3]} # displays b
> ####################################################
>
The code above does not apply the nameref attribute to an array.
Applying the nameref attribute to an array would be doing this:
$ declare -n ref[0]=a
bash: declare: ref[0]: reference variable cannot be an array
> In addition, when browsing the internet I see many questions regarding how to
> pass an array by reference, and the answers do not mention simply using a
> nameref. And if not using a nameref it appears that they are actually passing
> data by value which is inefficient, especially in the case of arrays.
>
> This leads me to believe that users who have read the documentation are not
> using this valuable feature, nor are they passing it along to others when
> answering related questions.
>
> Please let me know if I am missing something here or if the documentation
> should be corrected in this regard.
>
> Thank you!
>
>
>
>
>
>
>
>
>
> _______________________________________________________
>
> Reply to this item at:
>
> <https://savannah.gnu.org/bugs/?66460>
>
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--
Andreas (Kusalananda) Kähäri
Uppsala, Sweden
.
