Re: Valid characters for function names

[Chet Ramey]

On 11/26/19 12:31 PM, Stephane Chazelas wrote:
> 2019-11-26 11:14:38 -0500, Chet Ramey:
> [...]
> > This is a reasonable addition, with the caveat that `fname' is virtually
> > unlimited. It can't contain any quoted characters, or contain NUL (like any
> > bash string) or `$' (and that is dubious). You can even define a function
> > whose name contains a slash -- you'll just never be able to call it.
> [...]
>
> It can't contain delimiter characters like space, tab, newline
> (possibly other blanks in single-byte locales), |, &, ;, <, >,
> (, ) either.

Because trying it would require you to quote the character.

> I don't think you can create a function whose first character is
> #.

Same.

> You can't use = either if what's left of the first occurrence is
> a valid variable name (or a valid variable name followed by +).

Same, unless you use `function':

$ function foo=bar
> {
> echo a
> }
$ \foo=bar
a


> It seems you can't have a function name that is made of only
> decimal digits. (Defining it  as -123 or +123 is  OK though).

$ 1()
> {
> echo a
> }
$ 1
a

Current devel branch.

> You can't have a function with a an empty name.

That contains a NUL, but I get your point.

> zsh allows any name, and performs expansions and quote removal
> on the function name. So you can have a function with an empty
> name:

Not exactly relevant here.

Bottom line is basically that you need a WORD and anything that the
parser treats as higher precendence than a WORD requires quoting, which
disqualifies it as a function name. You can't have a reserved word
without using `function', either, for instance.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    address@hidden    http://tiswww.cwru.edu/~chet/