ramda/ramda

Practical functional Javascript

Scott Sauyet

@CrossEye

s/had/has

There should be no issues doing points-free recursion, but I'm not going to try an example on my phone.

David Chambers

@davidchambers

@CrossEye, have you ever found yourself writing code like this?

const f = R.pipe(
  a,
  b,
  c,
  d,
  e,
  x => f(x),
  g,
  h
);

I was wondering whether the Y combinator could obviate the need for the lambda.

Scott Sauyet

@CrossEye

I'm afraid it won't.

David Chambers

@davidchambers

No worries. :)

Scott Christopher

@scott-christopher

It's a silly example, but to show that the Y combinator allows for points-free recursion:

var min10 = Y(R.ifElse(R.compose(R.gte(R.__, 10), R.nthArg(1)),
                       R.nthArg(1),
                       R.useWith(R.call, [R.identity, R.inc])));

min10(12); // 12
min10(-3); // 10

the use of R.nthArg might be cheating a little, depending on your rules of points-free golf :D

Scott Christopher

@scott-christopher

it does also emphasise that you're probably not going to have something readable by the time you manage to get the recursive function to be points-free.

Scott Sauyet

@CrossEye

Yes, I was once again missing the point. It sounded easy to do recursion points-free until I tried it. Of course is not possible to do naively, but something like the Y-comb would allow it. But as always with the Y-combinator, it feels mostly like a trick. You prove that it can be done, but you don't use it for anything real.

Hardy Jones

@joneshf

function loop() {
  return loop;
}

seems pretty free of points

Tobias Pflug

@gilligan

and arguments

;)

craigdallimore @craigdallimore jumps in. Sees Y-Combinator. Jumps out.

Scott Sauyet

@CrossEye

And free of recursion

Tobias Pflug

@gilligan

I just realized that R.or(a,b) is merely a || b and does thus not return true or false as stated in the documentation but a a truthy or falsy value

Scott Sauyet

@CrossEye

@gilligan: if you want to see extended discussions about this, see #1218 and #1335. Perhaps not the most civil debates we've enter held, though.

If you pass booleans, though, you'll get a boolean.

Tobias Pflug

@gilligan

Oh that is a lot to read

;)

I skimmed some of it

Scott Sauyet

@CrossEye

I did say "extended". :smile:

Tobias Pflug

@gilligan

I wonder though- i get that there was resistance against dispatching but wouldn't Boolean( a || b) have made sense?

David Chambers

@davidchambers

I don't think Boolean(a || b) makes sense. One of the properties of (<|>) is that the return value is always one of the inputs. The operation represents a choice between two possibilities. It would not make sense for 0 <|> 1 to evaluate to True. That's my view, at any rate.

Tobias Pflug

@gilligan

but R.or is not in fact the alternative operator

and it does not pretend to be it either

Returns true if one or both of its arguments are true. Returns false if both arguments are false.

Scott Sauyet

@CrossEye

It wasn't about dispatching. I argued that the language's basic behavior is one of its good parts, and that keeping Ramda's behavior close to it was a good idea that didn't interfere with people who wanted to use it as a plain boolean operator.

David Chambers

@davidchambers

Well, if we restrict outselves to Boolean logic then we should only accept Boolean arguments. The handling of non-Boolean arguments is unspecified (I would prefer to throw, but that's not the Ramda way).

Scott Sauyet

@CrossEye

#1335 was about changing the documentation to make it look like a boolean-only function, even though it wasn't so under the covers. I wasn't in favour, but grew weary of fighting it.

Tobias Pflug

@gilligan

to me this kind of feels like fixing a problem by pretending it does not exist

I actually just did a PR where I used R.or(a,b) to pick a or b and someone commented "hey this should not work. R.or is documented to return true or false. You should use something else and file an upstream ticket" ;)

David Chambers

@davidchambers

S.or provides the "alternative" implementation, by the way.

Tobias Pflug

@gilligan

interesting ;)

just figured @CrossEye is on fp slack chat as well. i wish we could have the ui of slack combined with the practicality of gitter

David Chambers

@davidchambers

Would be nice!

Tobias Pflug

@gilligan

@davidchambers ever been on the fpslack chat ?

David Chambers

@davidchambers

No, I have not. My forays into the world of Slack have been limited so far. We use HipChat at Plaid. :\

Tobias Pflug

@gilligan

never used that

David Chambers

@davidchambers

You're not missing much.

Tobias Pflug

@gilligan

we actually have slack at holidaycheck

quite like it

@davidchambers do you think you have time to have another look at ramda/ramda#1529 later ?

David Chambers

@davidchambers

Once you've normalized the formatting of .eslintrc I'm happy to merge it. Thanks for all your work on this!

Tobias Pflug

@gilligan

oh sure, i'll just run jsonlint over it :)

David Chambers

@davidchambers

Lint the linter! :)

Tobias Pflug

@gilligan

oh.. yeah and there was actually a dangling comma in there haha

Tobias Pflug

@gilligan

@davidchambers fixed!

think the next PR I will try is adding jsverify tests

David Chambers

@davidchambers

That'll be sweet!

Where communities thrive

People

Repo info

Activity