On Tue, 12 Sept 2023, 00:35 David Brown via Std-Proposals, <
std-proposals_at_[hidden]> wrote:

> On 08/09/2023 23:32, Arthur O'Dwyer via Std-Proposals wrote:
> > On Fri, Sep 8, 2023 at 4:48 PM David Brown via Std-Proposals
> > <std-proposals_at_[hidden] <mailto:std-proposals_at_[hidden]>>
>
> > wrote:
> >
> >
> > It should even be possible to write something like :
> >
> > if (var <= none_of(opt1, opt2, opt3)) ...
> >
> > by having "none_of" return a type X for which there is an operator <=
> > (LHS, X) overload.
> >
> > But I would not recommend standardising on such a syntax unless
> people
> > agreed to use a similar syntax for many new features. And maybe it
> > would be best to have a new operator specifically for such purposes -
> > perhaps a two operand ~.
> >
> >
> > Or the previously proposed syntactic sugar |>, where `x |> y(z)` would
> > be rewritten in the front end into `y(x,z)` even when `y(z)` wouldn't be
> > well-formed on its own.
>
> I hadn't noticed that proposal, but yes, it would fit here. (Was there
> also a proposed "x <| y(z)" meaning "y(z, x)" ?


No, there wasn't. See
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1282r0.html and
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2011r1.html
and https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2672r0.html


I think that would be
> more natural in many cases, though the ordering of |> is definitely
> better in this particular situation.)
>
> >
> > LLVM's codebase already uses named methods for this sort of thing in
> > several places; e.g.
> > if (!Current.isOneOf(tok::comment, tok::caret)) ...
> > and I think that's a fine solution in general.
> >
> > Meanwhile, OP's proposed "after" snippet:
> > const OverloadedOperatorKind OOK = FD->getOverloadedOperator();
> > if (OOK [!] OO_EqualEqual, OO_ExclaimEqual, OO_Less,
> > OO_LessEqual, OO_Greater, OO_GreaterEqual, OO_Spaceship)
> > return false;
> > could actually be written today, using LLVM's existing codebase, as:
> > const OverloadedOperatorKind OOK = FD->getOverloadedOperator();
> > if (CXXOperatorCallExpr::isComparisonOp(OOK))
> > return false;
> > and then it just becomes a matter of maybe moving that utility function
> > somewhere with a better name (like, I don't know, dump it in Sema with
> > everything else).
> > I definitely /don't/ think OP's "after" snippet is an improvement over
> > LLVM's status quo. I think it'd be worse.
> >
>
> Agreed.
>
>
>
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