Re: select syntax violates the POLA

[Chet Ramey]

On 4/1/21 5:54 PM, Greywolf wrote:

> On 4/1/2021 8:57, Chet Ramey wrote:
> > It's more like `select' doesn't inherit some of the shell's special cases.
> >
> > >         select dir in ${d[@]}; do {
> > >         break;
> > >         } done;
> > >
> > >     ...but select breaks on the "} done;" syntax 
> >
> > Yes, you need a list terminator so that `done' is recognized as a reserved
> > word here. `;' is sufficient. Select doesn't allow the `done' unless it's
> > in a command position. Some of the other compound commands have special
> > cases, mostly inherited from the Bourne shell, to allow it.

I took a look at bash-1.14, where the `select' command first appeared. At
the time, it was identical to the `for' command -- which makes sense, since
the syntaxes are essentially identical (and internally, they are
represented the same way). They both used the `list' grammar production.

When I updated the grammar to use the `compound_list' production in
bash-2.0, to be closer to how POSIX specified the compound commands in the
POSIX grammar, I left the select command alone. It's been the same way
since late 1994, though bash-2.0 wasn't released until 1996.

I took this opportunity to examine the grammar again, and there's no good
reason `select' and `for' should be different -- they started out the same,
and they should both use compound_list now. So they will.

This presented an opportunity to marginally simplify the grammar, so it's a
win all around.

The change will be in the next devel branch push.

Chet

--
``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/