Syntax Proposal: Anonymous Arguments

Kenneth Powers ken at kenpowers.net
Fri Sep 23 18:35:06 UTC 2016


What proposal is "@" reserved for, by chance? I was trying to pick
something that both wasn't used and can't be the name of a variable (e.g.,
underscore). I saw another proposal for "?" for partially applying
functions, but that would be potentially ambiguous with the ternary
operator.

As for resolving ambiguity, why not just do what Scala does
<http://stackoverflow.com/questions/19916169/scala-arguments-of-nested-lambdas-with-short-syntax/19917720>?
It would seem to me that nesting these functions would be a sign you need
to refactor anyway.

As far as meriting its own syntax, that's why I referenced another language
where the implementors found that it did merit its own syntax (though the
underscore in Scala also does a lot more).

On Fri, Sep 23, 2016 at 2:00 PM, Jordan Harband <ljharb at gmail.com> wrote:

> In Scala, the ambiguity of the underscore causes lots of confusion when
> you have nested functions - how is that handled in your proposal?
>
> Bear in mind, I think it's a tough argument that `@ + 1` is so much better
> than `n => n + 1` that it warrants its own syntax.
>
> Separately, the "@" is reserved for an existing proposal, so you'd have to
> come up with different syntax anyways.
>
> On Fri, Sep 23, 2016 at 10:38 AM, Kenneth Powers <ken at kenpowers.net>
> wrote:
>
>> I have a proposal for new syntax in ES inspired by the placeholder syntax
>> in Scala Functions
>> <http://docs.scala-lang.org/overviews/quasiquotes/expression-details.html#function>
>> .
>>
>> Essentially, the idea would be to allow anonymous arguments. The most
>> simple example would be a function which takes one argument (as far as the
>> programmer is concerned):
>>
>>     [1, 2, 3].map(@ + 1)
>>
>> This would be the same thing as:
>>
>>     [1, 2, 3].map(n => n + 1)
>>
>> Just like in Scala, an anonymous function is created. This concept can be
>> further extended in ES:
>>
>>     [1, 2, 3].reduce(@0 + @1, 0)
>>
>> Which would be the same thing as:
>>
>>    [1, 2, 3].reduce((sum, n) => sum + n, 0)
>>
>> Thoughts?
>>
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>> es-discuss at mozilla.org
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>>
>>
>
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