2014-09-29 09:04:00 -0600, Eric Blake:
[...]
> > "The function is named fname; the application shall ensure that it is a
> > name (see XBD Name) and that it is not the name of a special built-in
> > utility."
> >
> > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_05
>
> Note that this particular requirement is on "the application" (aka the
> shell script defining the function) and NOT on "the implementation" (aka
> bash as the shell that is tracking the function definition). There are
> a number of places where there are requirements on a strictly conforming
> application, where if they violate that requirement, then they have
> subjected themselves to unspecified behavior, and that the shell can do
> whatever it deems makes the most sense. In other words, I _don't_ read
> this sentence of POSIX as requiring that 'bash -o posix' must reject
> arbitrary function names, only that a shell script trying to conform to
> POSIX must not attempt to define a function with such a name.
>
> I would expect something like "It shall be an error if fname is the name
> of a special built-in utility", as _that_ would be a hard requirement on
> bash, not just the application. Maybe we have a bug in the POSIX spec
> for a missing requirement.
I agree the requirement is on the application, and I can't see
why POSIX should force a shell to reject a function whose name
doesn't contain a valid identifier.
() are used for (...), $(...), $((...)) and in "case", but
outside of that should be quoted, so I suppose any shell can do
whatever they want with them. ksh/bash/zsh already use it for
globs or arrays for instance.
The function keyword is also reserved with undefined behavior,
so one shell could very well do:
function with weird name 'blah = blah' [
my function definition
]
Or:
'blah blah'() {
my function
}
(like zsh does).
Or:
()'blah blah'={ my function }
Or:
functions[blah blah]='my function'
(as in zsh, and again unspecified behaviour by POSIX).
None of which are valid POSIX shell syntax, so POSIX shells can
do whatever they want with them.
--
Stephane
