Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

S K definition of Y combinator #2

Open
benji6 opened this issue Oct 29, 2015 · 4 comments
Open

S K definition of Y combinator #2

benji6 opened this issue Oct 29, 2015 · 4 comments
Labels
help wanted

Comments

@benji6
Copy link
Owner

benji6 commented Oct 29, 2015

Y is the only included combinator that isn't defined and tested in terms of S and K. Help wanted!
@richardTowers
Copy link
Contributor

Presumably the problem here is that the naive approach overflows the stack because of eager evaluation?

Too hard for me I think...

@benji6
Copy link
Owner Author

benji6 commented Oct 30, 2015

Well the main problem is I cribbed all the S K derivations from http://www.angelfire.com/tx4/cus/combinator/birds.html but the Y definition has 11 left brackets and 10 right brackets and I can't work out what it's supposed to be...

I have quite a few definitions of Y in terms of other combinators including BML, SLL, UU and LO(LO), but my runtime just throws too much recursion errors with these.

So I'm stuck and don't know enough about this stuff!

@benji6
Copy link
Owner Author

benji6 commented Dec 18, 2015

S(S)(K)(S(K(S(S)((S(S(S)(K))))))(K))
http://tromp.github.io/cl/LC.pdf

@richardTowers
Copy link
Contributor

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
help wanted
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
2 participants
@richardTowers @benji6