BishBosh.Attribute.Direction

AUTHOR

Dr. Alistair Ward

DESCRIPTION

• Describes a direction in two parts; the sense of change in the x coordinate & the sense of change in the y coordinate.
• The IO-format uses a more concise & familiar format based on 8 points of the compass.
• CAVEAT: this separation of direction into orthogonal components is driven by the typical use-case, but requires that one guards against accidental construction of a degenerate 9th direction which defines neither a change in the x coordinate nor the y coordinate.

Types

Type-synonyms

type NDirections = Int

A number of directions.

type ByDirection = Array Direction

A boxed array indexed by direction, of arbitrary elements.

Data-types

data Direction

Define a direction by the sense of change to x & y coordinates.

Instances

Bounded Direction

Methods

minBound :: Direction

maxBound :: Direction

Eq Direction

Methods

(==) :: Direction -> Direction -> Bool

(/=) :: Direction -> Direction -> Bool

Ord Direction

Methods

compare :: Direction -> Direction -> Ordering

(<) :: Direction -> Direction -> Bool

(<=) :: Direction -> Direction -> Bool

(>) :: Direction -> Direction -> Bool

(>=) :: Direction -> Direction -> Bool

max :: Direction -> Direction -> Direction

min :: Direction -> Direction -> Direction

Read Direction

Methods

readsPrec :: Int -> ReadS Direction

readList :: ReadS [Direction]

readPrec :: ReadPrec Direction

readListPrec :: ReadPrec [Direction]

Show Direction

Methods

showsPrec :: Int -> Direction -> ShowS

show :: Direction -> String

showList :: [Direction] -> ShowS

Ix Direction

Methods

range :: (Direction, Direction) -> [Direction]

index :: (Direction, Direction) -> Direction -> Int

unsafeIndex :: (Direction, Direction) -> Direction -> Int

inRange :: (Direction, Direction) -> Direction -> Bool

rangeSize :: (Direction, Direction) -> Int

unsafeRangeSize :: (Direction, Direction) -> Int

XmlPickler Direction

Methods

xpickle :: PU Direction

Opposable Direction

Methods

getOpposite :: Direction -> Direction

Orientated Direction

Methods

isDiagonal :: Direction -> Bool

isParallel :: Direction -> Bool

isStraight :: Direction -> Bool

ReflectableOnY Direction

Methods

reflectOnY :: Direction -> Direction

ReflectableOnX Direction

Methods

reflectOnX :: Direction -> Direction

Constants

nw :: Direction

Constant direction.

n :: Direction

Constant direction.

ne :: Direction

Constant direction.

w :: Direction

Constant direction.

e :: Direction

Constant direction.

sw :: Direction

Constant direction.

s :: Direction

Constant direction.

se :: Direction

Constant direction.

tag :: String

Used to qualify XML.

nDistinctDirections :: NDirections

The constant number of distinct directions.

parallels :: [Direction]

The ordered directions in which a Rook can move.

diagonals :: [Direction]

The ordered directions in which a Bishop can move.

range :: [Direction]

The ordered directions in which royalty can move.

opposites :: [(Direction, Direction)]

• Returns a list of directions, each paired with its anti-parallel.
• CAVEAT: each direction only appears once in the list, on an arbitrary side of a pair.

Functions

advanceDirection :: LogicalColour -> Ordering

The y-direction in which a Pawn of the specified logical colour advances.

attackDirectionsForPawn :: LogicalColour -> [Direction]

The directions in which a Pawn can attack.

listArrayByDirection :: IArray a e => [e] -> a Direction e

Array-constructor.

Constructor

mkDirection

Arguments

:: Ordering

The sense of the change in the x-coordinate.

-> Ordering

The sense of the change in the y-coordinate.

-> Direction

Smart-constructor.

Predicates

areAligned :: Direction -> Direction -> Bool

Whether the two directions specified, are either parallel or anti-parallel.