Copyright	Copyright (c) 2007--2015 wren gayle romano
License	BSD
Maintainer	[email protected]
Stability	experimental
Portability	semi-portable (Rank2Types, MPTCs,...)
Safe Haskell	None
Language	Haskell98

Control.Unification.STVar

Description

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

Synopsis

Documentation

data STVar s t Source #

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) Source #
Methods lookupVar :: STVar s t -> STBinding s (Maybe (UTerm t (STVar s t))) Source # freeVar :: STBinding s (STVar s t) Source # newVar :: UTerm t (STVar s t) -> STBinding s (STVar s t) Source # bindVar :: STVar s t -> UTerm t (STVar s t) -> STBinding s () Source #
Eq (STVar s t) Source #
Methods (==) :: STVar s t -> STVar s t -> Bool # (/=) :: STVar s t -> STVar s t -> Bool #
Show (STVar s t) Source #
Methods showsPrec :: Int -> STVar s t -> ShowS # show :: STVar s t -> String # showList :: [STVar s t] -> ShowS #
Variable (STVar s t) Source #
Methods getVarID :: STVar s t -> Int Source #

data STBinding s a Source #

A monad for handling STVar bindings.

Instances

Unifiable t => BindingMonad t (STVar s t) (STBinding s) Source #
Methods lookupVar :: STVar s t -> STBinding s (Maybe (UTerm t (STVar s t))) Source # freeVar :: STBinding s (STVar s t) Source # newVar :: UTerm t (STVar s t) -> STBinding s (STVar s t) Source # bindVar :: STVar s t -> UTerm t (STVar s t) -> STBinding s () Source #
Monad (STBinding s) Source #
Methods (>>=) :: STBinding s a -> (a -> STBinding s b) -> STBinding s b # (>>) :: STBinding s a -> STBinding s b -> STBinding s b # return :: a -> STBinding s a # fail :: String -> STBinding s a #
Functor (STBinding s) Source #
Methods fmap :: (a -> b) -> STBinding s a -> STBinding s b # (<$) :: a -> STBinding s b -> STBinding s a #
Applicative (STBinding s) Source #
Methods pure :: a -> STBinding s a # (<>) :: STBinding s (a -> b) -> STBinding s a -> STBinding s b # (>) :: STBinding s a -> STBinding s b -> STBinding s b # (<*) :: STBinding s a -> STBinding s b -> STBinding s a #

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

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.