# log-e-sappho

experimental type system implementation

## sappho grammar

```
s, t ::= s | t              (disjunction, a.k.a. union)
       | s & t              (conjunction, a.k.a. intersection)
       | s => t             (implication)
       | s -> t             (arrow, a.k.a. function)
       | forall x . t       (forall, polymorphic)
       | box t              (box, modular logic)
       | a [t..]            (type operator application)
       | x                  (variable)
       | n                  (nominal)
       | true               (true, a.k.a. top)
       | false              (false, a.k.a. bottom)
       | { m : t }          (member, a.k.a. atomic record)


x ∈ var
n ∈ nominal
a ∈ opname
```