On Sat, 30 Aug 2025 at 05:26, Chet Ramey <chet.ra...@case.edu> wrote:
> On 8/29/25 1:26 PM, Martin D Kealey wrote: > > > /In early proposals, a form $[expression] was used. It was functionally > > equivalent to the "$(())" of the current text, but objections were > lodged > > that the 1988 KornShell had already implemented "$(())" and there was no > > compelling reason to invent yet another syntax. Furthermore, the "$[]" > > syntax had a minor incompatibility involving the patterns in case > statements./ > > > > The "no compelling reason" seems odd, like nobody was bothered to think > > about it. > > I think that's not the case, since every objection has to be considered and > get a response. > I meant, it seems like they didn't think about possible "compelling reasons" for anyone other than existing implementers, and therefore could not rebut the objection. The inability to parse without backtracking means that implementations have to be more complicated, and therefore more bug-prone. From the viewpoint of writing a new shell, that sounds like a compelling reason to me. That said, perhaps a backtracking framework would simplify the implementation of some lexical scoped "compatibility" modes, so maybe it's a pill worth swallowing once. > "If that falls" generally implying that the parser has to support > arbitrary backtracking, > > Not really arbitrary. Arbitrary in the sense of not having a fixed size limit, while not allowing infinite input. I seem to be having a weird day with terminology. OK. I suggest you take a run at filing an interpretation request, > keeping in mind that the language you're citing is non-normative and the > restrictions on conforming applications. > Does that mean writing to some...@opengroup.org, or using the problem reporting page? -Martin
