Re: IFS field splitting doesn't conform with POSIX

[Felipe Contreras]

On Thu, Mar 30, 2023 at 1:20 PM Lawrence Velázquez <vq@larryv.me> wrote:
> On Thu, Mar 30, 2023, at 2:25 PM, Felipe Contreras wrote:

> > The challenge is in deciding what they *should* do, which is not
> > descriptive, but prescriptive.
>
> The Austin Group does not see its role as prescriptive, although
> during discussions implementers are often open to modifying their
> implementations to achieve consensus.  If many implementers agree
> to make a change, the result may appear prescriptive.  (A recent
> example is <https://austingroupbugs.net/view.php?id=1629>.)

In that example they are discussing whether or not to make that
behavior a *requirement*. That is prescriptive.

> >> If what it says differs from what the majority of shells do, then it's
> >> POSIX that is wrong.
> >
> > Then there is no point in looking at the standard, since we know what
> > it should say
>
> The standard is a reference that describes a set of broadly common
> behaviors.  Not everyone is interested in researching and testing
> an assortment of implementations whenever they want to determine
> whether a behavior is portable.
>
> (Also: bash, dash, ksh, and zsh are not the only shells that exist.)

Precisely because they are not the only shells that exist, an
agreement between current implementers--which they themselves might
see as descriptive of their implementations--results in text that says
"the shell shall", which is prescriptive.

If I write a new shell (which I am seriously considering) which aims
to be called POSIX-compatible, that "shall" is 100% prescriptive.

-- 
Felipe Contreras