On Thu, Mar 30, 2023 at 1:20 PM Lawrence Velázquez <v...@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
