Data.Propagator.Change

This module exports the types and functions needed to describe changes of cell values.

Documentation

data Change a

A type which describes a potential change of a cell value.

Constructors

Changed a

Indicates that a cell value has been changed to the new value a.

Unchanged

Indicates that a cell value did not change, i.e. needs no propagation.

Incompatible

Indicates that a new cell value contradicts the one that is already stored in the cell.

Instances

Eq a => Eq (Change a)

Defined in Data.Propagator.Change

Methods

(==) :: Change a -> Change a -> Bool

(/=) :: Change a -> Change a -> Bool

Show a => Show (Change a)

Defined in Data.Propagator.Change

Methods

showsPrec :: Int -> Change a -> ShowS

show :: Change a -> String

showList :: [Change a] -> ShowS