I don't think we've reached the point of such conventions yet. And there's some history here, in --> not having done anything in the early days except possibly slow things down, and between --> and 'returns' (which is now deprecated).
On Thu, Oct 4, 2018 at 3:13 PM Trey Harris <t...@lopsa.org> wrote: > Right; that's what I meant by "stylistically" — a `--> Mu` can highlight > that something is being returned (and that side-effects are not the primary > purpose), while nothing indicates that the return value, though it exists, > is incidental and probably from "falling off the end" or using `return` as > a control-flow jump. > On Thu, Oct 4, 2018 at 15:04 Brandon Allbery <allber...@gmail.com> wrote: > >> Arguably it should be --> Any, since Mu vs. Any has meaning with respect >> to Junctions. But in this case it's just not stating a redundancy. >> >> The way you'd phrased it makes it sound like it's an explicit >> no-meaningful-result, as opposed to 'we don't know or care'. >> >> On Thu, Oct 4, 2018 at 3:02 PM Trey Harris <t...@lopsa.org> wrote: >> >>> Ah (replying to both Brandon and JJ since their replies crossed): >>> >>> So `--> Mu` is not a sufficient and/or correct return constraint for >>> things like AT-POS because why, then? >>> On Thu, Oct 4, 2018 at 14:56 Brandon Allbery <allber...@gmail.com> >>> wrote: >>> >>>> I think they meant more like my AT-POS example: the point is the return >>>> value, but you can't say ahead of time what type it will have. >>>> >>>> On Thu, Oct 4, 2018 at 2:48 PM Trey Harris <t...@lopsa.org> wrote: >>>> >>>>> >>>>> >>>>> On Thu, Oct 4, 2018 at 02:13 JJ Merelo <jjmer...@gmail.com> wrote: >>>>> >>>>>> >>>>>> >>>>>> El jue., 4 oct. 2018 a las 3:36, Trey Harris (<t...@lopsa.org>) >>>>>> escribió: >>>>>> >>>>>>> _All_ routines in Perl 6 return _something._ A lack of a "-->" >>>>>>> simply indicates stylistically that the return is not useful because >>>>>>> it's >>>>>>> whatever "falls off the end". (There's a bit of variance here as I'm not >>>>>>> sure it's a convention everyone has followed.) It's equivalent to "--> >>>>>>> Mu" >>>>>>> because anything that could "fall of the end" is Mu. >>>>>>> >>>>>> >>>>>> No, it means that it's not constrained to a type. It can still return >>>>>> something, but it can be anything. >>>>>> >>>>> >>>>> >>>>> I get all that, except for the "No" at the front. ;-) >>>>> >>>>> Or were you talking about the "not useful" bit? Yes, of course in any >>>>> given codebase, the lack of a return value has no more or less meaning >>>>> than >>>>> a lack of any constraint. The programmer may not like using constraints at >>>>> all and treats Perl 6 like Perl 5 in the respect of wanting arbitrarily >>>>> mungible values. >>>>> >>>>> But the word "stylistically" was important, as I was responding to >>>>> Todd's question about the docs—I think a lack of a return value in the >>>>> docs >>>>> (at least, the ones I could come up with in a grep pattern on my checkout >>>>> of docs) does tend to indicate that the return is not useful, that the >>>>> routine is a "procedure" run for its side effects rather than for >>>>> evaluation. >>>>> >>>>> Is that what you meant? >>>>> >>>>> If you were saying in "it can still return something, but can be >>>>> anything", that "anything ⊃ (is a strict superset of) `Mu`", then I >>>>> don't understand, because I thought all values conformed to Mu. >>>>> >>>>> >>>> >>>> -- >>>> brandon s allbery kf8nh >>>> allber...@gmail.com >>>> >>> >> >> -- >> brandon s allbery kf8nh >> allber...@gmail.com >> > -- brandon s allbery kf8nh allber...@gmail.com
