bernerbrau

Monad

A type T is a subtype of type M[X] iff:

1. There exists a function unit of type X → M[X]
2. There exists a function bind of type (M[X], X → R) → R
3. For all x:X and f:X→R : bind(unit(x),f) ≡ f(x)

Notes

The natural inclination is to ask, "What are the semantics here?" but it turns out that the semantics depend wholly on the