Function Abstraction | Symbol | Bird | CR¹ Combinator | CH² Combinator | Elementary³ | Haskell | APL | BQN |
λabc.ac(bc) | S | Starling | S | S | <*> / ap | ⟜ | ||
λab.a | K | Kestrel | K | K | ✅ | const | ⊢ | ⊢ |
λa.a | I | Identity | SKK | SKK | ✅ | id | ⊣⊢ | ⊣⊢ |
λab.b | κ | Kite | KI | KI | ⊣ | ⊣ | ||
λab.abb | W | Warbler | C(BMR) | CSK | ✅ | join | ⍨ | ˜ |
λabc.acb | C | Cardinal | S(BBS)(KK) | B(ΦBS)KK | ✅ | flip | ⍨ | ˜ |
λabc.a(bc) | B | Bluebird | S(KS)K | S(KS)K | ✅ | . | ∘⍤⍥ 2T | ∘○ 2T |
λabcd.a(bcd) | B₁ | Blackbird | BBB | DB | .: | ⍤ 2T | ∘ 2T | |
λabcde.a(bcde) | B2 | Bunting | B(BBB)B | DB₁ | ||||
λabcd.a(b(cd)) | B3 | Becard | B(BB)B | BDB | ||||
λabcd.ab(cd) | D | Dove | BB | BB | ∘ | ⟜ | ||
λabcd.a(bd)(cd) | Φ | Phoenix | - | B₁SB | liftA2 | 3T | 3T | |
λabcd.a(bc)(bd) | Ψ | Psi | - | B(SΦCB)B | on | ⍥ | ○ | |
λabcde.abc(de) | D1 | Dickcissel | B(BB) | BD | ||||
λabcde.a(bc)(de) | D2 | Dovekies | BB(BB) | DD | ||||
λabcde.ab(cde) | E | Eagle | B(BBB) | BB₁ | ||||
λabcde.a(bde)(cde) | Φ1 | Pheasant | - | BΦΦ | 3T | 3T | ||
λabcdefg.a(bcd)(efg) | Ê | Bald Eagle | B(BBB)(B(BBB)) | D₂D₂D |
1 - CR = Chris Rathman (combinator spellings taken from his site)
2 - CH = Conor Hoekstra (combinator spellings generated from C++ program)
3 - Elementary combinators are listed in Chapter 5 of Combinatory Logic: Volume I
