Control.Unification.STVar

This module defines an implementation of unification variables using the ST monad.

Documentation

data STVar s t

Unification variables implemented by STRefs. In addition to the STRef for the term itself, we also track the variable's ID (to support visited-sets).

Instances

Unifiable t => BindingMonad t (STVar s t) (STBinding s)

Eq (STVar s t)

Show (STVar s t)

Variable (STVar s t)

data STBinding s a

A monad for handling STVar bindings.

Instances

Unifiable t => BindingMonad t (STVar s t) (STBinding s)

Monad (STBinding s)

Functor (STBinding s)

Applicative (STBinding s)

runSTBinding :: (forall s. STBinding s a) -> a

Run the ST ranked binding monad. N.B., because STVar are rank-2 quantified, this guarantees that the return value has no such references. However, in order to remove the references from terms, you'll need to explicitly apply the bindings and ground the term.