Re: unset does not remove functions like a[b] unless -f is specified

[Chet Ramey]

On 2/3/23 7:01 PM, Robert Elz wrote:
>      Date:        Fri, 3 Feb 2023 11:22:23 -0500
>      From:        Chet Ramey <chet.ramey@case.edu>
>      Message-ID:  <f1e549d5-59b0-e0af-c02f-fc3c8e50fa70@case.edu>
>
>    | > Hmm, I wonder whether <(:) could be a valid function name,
>    | > if it expands to something like /dev/fd/63?
>    |
>    | Bash doesn't allow that; it treats the < like a $ in this case.
>
> If unquoted, the '<' would be an operator (redirection operator)
> (or with bash extensions, <( is probably the operator there - doesn't
> matter here) - operators cannot be part of a word, that violates the
> tokenisation rules.  

It's not an operator. It's a word expansion, just like $(). It doesn't
delimit words, and it doesn't require quoting. It's not documented to
be one of the disallowed characters (character sequence in this case), and
probably should not be.


> I'm not sure why bash prohibits quotes around function names, to allow
> names containing operators, and white space, as well as the expansion
> characters ($ ` * ? and [), and the quote characters themselves.

It's probably inherited from reserved words. The reasons have been lost
to time.

> Is there something about the implementation which would fail if that
> rule was removed?

Probably not.

--
``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/