Function composition vs pipeline

Viktor Kronvall viktor.kronvall at gmail.com
Sat Feb 24 05:46:15 UTC 2018


I don’t know the implications but I could easily imagine the pipeline
proposal being extended to not taking any input on the left hand side and
effectively represent composition in the opposite direction.

For example:
```
let h = |> f |> g
h(2) //g(f(2))
```

That said, the point holds for the proposal in its current state. Being
able to compose functions
leads to much more expressivity than if you have
to call the pipeline (and collapse) where it is defined.
2018年2月24日(土) 14:32 Naveen Chawla <naveen.chwl at gmail.com>:

> The function composition operator composes function pipelines into
> functions for later use and/or further composition. Those functions still
> need to be called via the existing `()` syntax, so it doesn't offer a
> different way of calling functions as such.
>
> The function pipeline operator calls the function pipeline immediately, so
> it is really only a different way of calling functions.
>
> On Fri, 23 Feb 2018 at 12:37 Jordan Harband <ljharb at gmail.com> wrote:
>
>> How is either operator not "a different way of calling functions"?
>>
>> On Thu, Feb 22, 2018 at 8:34 PM, Naveen Chawla <naveen.chwl at gmail.com>
>> wrote:
>>
>>> I was just thinking about the relative merits and coexistence (or not)
>>> of function composition operator and function pipeline operator features:
>>>
>>> e.g.
>>>
>>> https://github.com/TheNavigateur/proposal-pipeline-operator-for-function-composition
>>> https://github.com/tc39/proposal-pipeline-operator
>>>
>>> They can of course co-exist, but there is overlap only in the respect
>>> that both allow function pipelines to be called from left to right (except
>>> the input parameter in the case of the composition feature, which requires
>>> existing bracket syntax to be used to call it). If one were to be chosen,
>>> would say that a function composition operator adds a whole new dimension
>>> of expressive power to the language, whereas a pipeline operator only
>>> offers a different way of calling functions.
>>>
>>> I was wondering about all of your thoughts about whether you'd prefer
>>> only the pipeline operator, only the composition operator, or both, or
>>> neither to be added to the language (these are pretty much all the
>>> possibilities), and why.
>>>
>>> _______________________________________________
>>> es-discuss mailing list
>>> es-discuss at mozilla.org
>>> https://mail.mozilla.org/listinfo/es-discuss
>>>
>>>
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