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 > _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
