Can you clarify in what sense you see this as a special case of that proposal? To put it in very simple terms, we would like to do something like `array.map(.name)`.
On Tue, Dec 3, 2019 at 3:33 AM Isiah Meadows <cont...@isiahmeadows.com> wrote: > BTW, all this is very much just a special case of this (existing stage > 1) proposal, and is part of why it exists: > https://github.com/tc39/proposal-partial-application > > I do find it surprising that property access isn't addressed there, > but it seems like it was likely just overlooked - it has no mention in > the repo, in the open issues, or even in the closed issues or any of > the open or closed pull requests. > > ----- > > Isiah Meadows > cont...@isiahmeadows.com > www.isiahmeadows.com > > On Tue, Dec 3, 2019 at 5:43 AM Michael Luder-Rosefield > <rosyatran...@gmail.com> wrote: > > > > At the cost of adding more code, but giving more power, perhaps what we > want is something akin to Kotlin's `it` keyword: > > > https://kotlinlang.org/docs/reference/lambdas.html?_ga=2.238822404.500195435.1575368476-1345353619.1575368476#it-implicit-name-of-a-single-parameter > > > > it: implicit name of a single parameter > > It's very common that a lambda expression has only one parameter. > > If the compiler can figure the signature out itself, it is allowed not > to declare the only parameter and omit ->. The parameter will be implicitly > declared under the name it: > > ints.filter { it > 0 } // this literal is of type '(it: Int) -> Boolean' > > > > > > What we'd want is something concise and non-ambiguous to fulfill the > same role; something that cannot currently be a valid identifier, maybe. > This is the point where I start scanning the keyboard for underutilised > symbols... I'm thinking the hash symbol would work. To re-use the original > example: > > > > ```js > > const activeProducts = products.filter(#.active); > > const productNames = products.map(#.name); > > const sortedProducts = _.sortBy(products, #.name); > > const { true: activeProducts, false: inactiveProducts } = > _.groupBy(products, #.active); > > ``` > > > > It makes intuitive sense in 2 ways, I think; # makes you think of the > object hash you're extracting a property from, and also is familiar as > something's id from CSS selectors. > > > > We could also extend it to represent multiple parameters: # is also > aliased as #0, the 2nd parameter is #1, etc. > > > > Further, dynamic properties would work too: `const fooProducts = > products.filter(#[foo]); > > -------------------------- > > Dammit babies, you've got to be kind. > > > > > > On Mon, 2 Dec 2019 at 22:32, Waldemar Horwat <walde...@google.com> > wrote: > >> > >> On 11/24/19 9:17 PM, Bob Myers wrote: > >> > FWIW, the syntax `.propName` does appear to be syntactically > unambiguous. > >> > >> It conflicts with contextual keywords such as `new . target`. > >> > >> Waldemar > >> _______________________________________________ > >> es-discuss mailing list > >> es-discuss@mozilla.org > >> https://mail.mozilla.org/listinfo/es-discuss > > > > _______________________________________________ > > es-discuss mailing list > > es-discuss@mozilla.org > > https://mail.mozilla.org/listinfo/es-discuss > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss >
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