Swift style syntax

[Isiah Meadows]

Steve, I have little problem with whatever ends up the case, as long as
it's shorter than `(x, y) => x + y`. The current idea was inspired by
Swift's `list.sort(>)` and `list.reduce(0, +)`.

On Tue, Oct 13, 2015, 12:34 Steve Fink <sphink at gmail.com> wrote:

> On 10/12/2015 11:06 PM, Isiah Meadows wrote:
> >
> > +1 for operators as functions (I frequently is them in languages that
> > have them), but there is an ambiguous case that frequently gets me:
> > does `(-)` represent subtraction or negation. It's usually the former
> > in languages with operators as functions.
> >
> > But here's a couple other potential syntactical ambiguities, dealing
> > with ASI:
> >
> > ```js
> > // Is this `x => f(x)` or `x = (>); f(x)`
> > x =>
> > f(x)
> >
> > // Is this `-x` or `-; x`?
> > -
> > x
> > ```
> >
> > Those can be addressed with a cover production to be used for
> > expression statements and direct value assignment, requiring
> > parentheses to clarify the latter case in each.
> >
> > A similar ambiguity problem, arguably harder to resolve, is partially
> > applied subtraction, such as `(- 2)`. Is that a -2 or is it equivalent
> > to `x => x - 2`? I will caution on this idea, as I know that's the
> > next logical step.
> >
>
> It it just me? I find all this talk of bare operators to be
> completely... uh, I'll go with "inadvisable".
>
> I can believe that you could carve out an unambiguous path through the
> grammar. But (a) it's going the way of line noise, (b) it uses up lots
> of possibilities for future expansion on something that isn't all that
> useful in the first place, and (c) it seems to be choosing concise
> syntax over readability in a big way.
>
> C++ has an 'operator' keyword (and even then it comes out pretty ugly --
> operator()(), anyone?) Perl6 has better syntax (syntax syntax?) for this:
>
>      infix:<+>
>      circumfix:«( )»
>
> or whatever. And of course Python uses double __underscores__ with ASCII
> operator names. All those are preferable to bare operators, to me.
>
>     -compose(+, *)(++x, +(3, 4), --y) - (3 + 4) - -(1, 2);
>
> I don't really *want* that to parse! At least make it
>
>    list.sort(#`>`);
>
> or something.
>
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