Name of function taking a function and a value and returning value after apply function to value

Question

I'm curious if there is a specific name for this function in Lambda Calculus

const whatsMyName = f => a => { f(a); return a }

Also, would this be the correct signature?

// (f -> a -> b) -> a -> a

Example

const trace = whatsMyName(console.log)

Thanks!

-- EDIT:

This is just S(K), or Substitution(Constant). I was able to work this out, a more elaborate answer with good references:

Functional programming construct for composing identity and side effect

Specific Answer

https://stackoverflow.com/a/46120634/1560484

Thanks @ftor for comment!

and what is the point of applying function to argument when you don't return result of this application, but argument instead? and why do you need to return argument, you already have it? i'm just trying to understand your intentions/scenario. — rsm, Mar 01 '18 at 00:10
One might call this a _method_. Could be a _[closure](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Closures)_? — Ronnie Royston, Mar 01 '18 at 00:20
I'm curious if it has a specific name as a combinator in Lambda Calculus — Babakness, Mar 01 '18 at 00:20
@RonRoyston Are you saying that this would be called "method" in Lambda Calculus? Sorry for confusion. — Babakness, Mar 01 '18 at 00:23
Answer is probably “no”, regardless of whether you consider `f`’s side effects. — Ry-, Mar 01 '18 at 00:30
I've added an answer that derives this behavior from other combinators. — Babakness, Mar 01 '18 at 01:05
In the lambda calculus, there is no sequencing and that function does not exist. — molbdnilo, Mar 01 '18 at 08:46

Babakness · Answer 1 · 2018-03-01T18:17:29.607

0

I figured out how to construct it from other combinators. There may not be a special name for it, it is simply derived from K (constant) and S (substitution).

 const K = x => y => x
 const S = f => g => x => f(x)(g(x));
 const whatsMyName = S(K)
 const trace = whatsMyName(console.log)

Edit:

The comment by @ftor points to a more complete answer:

Functional programming construct for composing identity and side effect

edited Mar 01 '18 at 18:17

answered Mar 01 '18 at 01:04

Babakness

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look into SKI combinator calculus. Related [q&a](https://stackoverflow.com/a/46120634/6445533). – Mar 01 '18 at 09:28
Wow! Thanks for that link, went straight to my bookmarks on functional programming! – Babakness Mar 01 '18 at 18:09

Name of function taking a function and a value and returning value after apply function to value

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