I failed to mention that clearly enough... In most functional languages, that's binary. And I think that should be the same for JS. It's surprising otherwise.
I'd say the closest precedent here I know of would be LiveScript, where the operator is treated as binary when used as a function. Most functional languages have separate functions for subtraction and negation, including Haskell (`-` vs `negate`) and OCaml (`-` and `.-` vs `negate` and `fnegate`). On Tue, Oct 13, 2015, 04:13 Andreas Rossberg <[email protected]> wrote: > All this is well-known from functional languages, with well-known > solutions. The only real problem is: > > let f = (-) > > Is this unary or binary `-`? > > On 13 October 2015 at 08:06, Isiah Meadows <[email protected]> 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. > > > > > > On Mon, Oct 12, 2015, 06:43 Thomas <[email protected]> > wrote: > >> > >> > >> Is it possible to extend JavaScript syntax to support Swift style block > >> syntax[1]? > >> > >> In Swift it's possible to omit return keyword > >> ``` > >> > >> reversed = names.sort( { s1, s2 in s1 > s2 } ) > >> > >> ``` > >> > >> > >> As you note below this is already possible in es6, and might I add, has > >> much more intuitive syntax in Es6. The swift syntax looks like a list > >> comprehension gone wrong. > >> > >> or omit argument declaration like this: > >> > >> ``` > >> > >> reversed = names.sort( { $0 > $1 } ) > >> > >> ``` > >> > >> > >> I for one think this is a bad idea - use rest arguments instead. It's > >> pretty terrible as far as readability goes, although I'd like to see > more > >> examples of it being used in Swift code. > >> > >> or apply an operator to arguments of a function > >> > >> ``` > >> > >> reversed = names.sort(>) > >> > >> ``` > >> > >> > >> This might actually be possible - I can't think of any ambiguous > >> situations for passing operators as if they were first class functions. > If > >> it is possible, I'd like to see this done. > >> > >> We have the first feature in ES2015 already: > >> > >> ``` > >> let sorted = names.sort((a, b)=> a > b); > >> ``` > >> > >> But for omitting argument declaration we need to find an alternative to > >> $0, $1... since those are valid variable names in JS. Maybe we can use > #0, > >> #1... instead. > >> > >> This is very useful for functional programming aspect of JS. For example > >> in a filter function: > >> > >> ``` > >> let passed = objs.filter(#0.passed) > >> ``` > >> > >> > >> [1][ > https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Closures.html > ] > >> > >> _______________________________________________ > >> es-discuss mailing list > >> [email protected] > >> https://mail.mozilla.org/listinfo/es-discuss > >> > >> _______________________________________________ > >> es-discuss mailing list > >> [email protected] > >> https://mail.mozilla.org/listinfo/es-discuss > > > > > > _______________________________________________ > > es-discuss mailing list > > [email protected] > > https://mail.mozilla.org/listinfo/es-discuss > > >
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