Combinators

BCKW combinators

Ramda have the B, C, K and W from the BCKW system

• B (composition) : R.map or R.compose ✅
• C (flip) : R.flip ✅
• K (known as Prelude#const) : R.always ✅
• W (duplication) : R.unnest ✅

SKI combinators

Ramda have S, K and I from the SKI system

• S (substitution) : R.ap ✅
• K (constant, also known as Prelude#const) : R.always ✅
• I (identity) : R.identity ✅

// substitution
const S = curry((f, g, x) => f(x, g(x)));

Other known combinators

• A (apply) : R.call (IMHO R.apply is valid too) ✅
• T (thrush) : R.applyTo ✅
• Y (fix-point) : RA.Y (fascinating one) ✅
• P (Psi, also known as Data.Function#on) : ❌

// Psi
const P = curry((f, g, x, y) => f(g(x), g(y)));

We can imagine a variadic arguments version of this one.

---

Study material - https://gist.github.com/Avaq/1f0636ec5c8d6aed2e45