License	GNU LGPLv3
Maintainer	paul.bittner@uni-ulm.de
Safe Haskell	Safe

NullPropositions

Contents

Orphan instances

Description

Definition and operations on the ternary logic with null. In the paper, we call formulas of this logic nullable propositional formulas. Reuses PropositionalFormulas.

Synopsis

type NullableFormula a = Maybe (PropositionalFormula a)
isnull :: NullableFormula a -> Bool
notnull :: NullableFormula a -> Bool
assure :: NullableFormula a -> PropositionalFormula a
nullable_simplify :: NullableFormula a -> NullableFormula a
prettyPrint :: Show a => Maybe a -> String

Documentation

type NullableFormula a = Maybe (PropositionalFormula a) Source #

Data type for the ternary logic by Sobocinski. The Nothing case represents null as used in our paper.

isnull :: NullableFormula a -> Bool Source #

Returns true iff the given formula is the value null.

notnull :: NullableFormula a -> Bool Source #

Returns false iff the given formula is the value null.

assure :: NullableFormula a -> PropositionalFormula a Source #

Converts the given nullable formula to a propositional formula, assuming that the given formula is not null. Crashes otherwise.

nullable_simplify :: NullableFormula a -> NullableFormula a Source #

Simplifies the given formula. Uses simplify.

prettyPrint :: Show a => Maybe a -> String Source #

Pretty Printing for nullable objects such as the nullable propositional logic.

Orphan instances

Logic a => Logic (Maybe a) Source #	Any `Logic` can be lifted to a logic on `Maybe`. This adds a new value `Nothing` to the values of the given logic. In particular, `NullableFormula` is thus a `Logic`.
Instance details Methods ltrue :: Maybe a Source # lfalse :: Maybe a Source # lvalues :: [Maybe a] Source # lnot :: Maybe a -> Maybe a Source # land :: [Maybe a] -> Maybe a Source # lor :: [Maybe a] -> Maybe a Source # limplies :: Maybe a -> Maybe a -> Maybe a Source # lequals :: Maybe a -> Maybe a -> Maybe a Source # leval :: (Maybe a -> Maybe a) -> Maybe a -> Maybe a Source #