{-# LANGUAGE MultiParamTypeClasses #-} 

{- Spatial Reference Frames

An implementation of Thora Tenbrink, 2011. Reference frames of space and time in language, Journal of Pragmatics 43:704-722.

The code is a simulation, providing an executable model to produce valid descriptions from situations.
It will evolve into an ontology of spatial reference, specifying the conceptualizations in terms of roles. 

Contributions of the approach:
- distinguishes external and internal relationships
- represents absolute reference frames consistently with intrinsic and relative frames
- includes dynamic situations 
- separates roles (such as providing a perspective) from properties and affordances (such as having an intrinsic orientation)
- distinguishes spatial and discourse roles and abstracts these from concrete linguistic expressions
- maps to existing approaches:
	Levinson 1996/2003
	Herrmann 1990
	Retz-Schmidt 1988
	Pederson 2003
	Talmy 2000
	Grabowski 1999
	Bohnemeyer? (nicht geprüft), 
	Frank 1998.

Formalization approach:
- entities only exist in situations 
	they always have a position and can have an orientation and/or motion
	- box, room, wall, town, country, place: -o -m
	- chair, queue, river: +o -m
	- ball, wheel: -o +m
	- person, mouse, car: +o +m
- 2 kinds of cognitive roles filled by entities in a situation 
	discourse roles: speaker, addressee, participant (corresponding to grammatical first, second, third person)
	spatial roles: locatum, relatum, perspective (optionally with origin)

To Do:
- try 3 step role filling as mappings (from empty to filled situations to discourse roles to spatial roles)
- or reversed? start with sentence slots, fill them by spatial roles, then by entities
- or generate possible combinations of roles and situations?
- deal with names vs nouns
- produce multiple sentences to capture alternatives like encounter, directional, etc.?
- rethink 13 and 18, introduce inverse orientation (rather than inverse perspective, which is wrong)
- check: which roles are actually used in computations!
- test with 1d cases
- extend to 3d
- tie to DOLCE / GUM
- extend to multiple fillers per role
- test with other languages

(c) Werner Kuhn
Last modified: 9 Mar 2011 (WK) 
-}

module SpatialReference where

-- positions as individual raster cells
type Position = (Int, Int)
outside = (-9,-9) -- dummy value, never accessed

-- footprints as sets of positions
type Footprint = [Position]

-- directions as free (!) unit vectors
type Direction = (Int, Int)

-- meaningful direction terms to use in the code
none, forward, backward, right, left:: Direction
none = (0,0)
forward = (0,1)
backward = (0,-1)
right = (1,0)
left = (-1,0)

invert :: Direction -> Direction
invert (0,0) = (0,0)
invert (0,1) = (0,-1)
invert (1,0) = (-1,0)
invert (-1,0) = (1,0)

-- the direction from a position to another
fromTo :: Position -> Position -> Direction
fromTo p1 p2 =  (signum (fst p2 - fst p1), signum (snd p2 - snd p1))

-- the first direction seen from the second
relativeTo :: Direction -> Direction -> Direction 
relativeTo d1 d2 = (snd d2 * fst d1 - fst d2 * snd d1, fst d2 * fst d1 + snd d2 * snd d1) 

-- the view taken of a situation
data View = Field | Object deriving Eq

----------------------------------------------------------------------
-- entities
-- position, orientation, motion defined in the local (situation) system

data Entity = Entity {	noun :: String,
						position :: Position, 
						footprint :: Footprint,
						orientation :: Direction, 
						motion :: Direction} deriving (Eq, Show)

box75 = Entity {noun = "box ", position = (7,5), footprint = [(7,5)], orientation = none, motion = none}
box73 = Entity {noun = "box ", position = (7,3), footprint = [(7,3)], orientation = none, motion = none}
box65 = Entity {noun = "box ", position = (6,5), footprint = [(6,5)], orientation = none, motion = none}
box95 = Entity {noun = "box ", position = (9,5), footprint = [(9,5)], orientation = none, motion = none}
person55 = Entity {noun = "person ", position = (5,5), footprint = [(5,5)], orientation = right, motion = none}
person75 = Entity {noun = "person ", position = (7,5), footprint = [(7,5)], orientation = right, motion = none}
person73 = Entity {noun = "person ", position = (7,3), footprint = [(7,3)], orientation = right, motion = none}
chair55 = Entity {noun = "chair ", position = (5,5), footprint = [(5,5)], orientation = right, motion = none}
external = Entity {noun = "person ", position = outside, footprint = [outside], orientation = right, motion = none}
ball75 = Entity {noun = "ball ", position = (7,5), footprint = [(7,5)], orientation = none, motion = none}
wall105 = Entity {noun = "wall ", position = (10,5), footprint = [(10,4), (10,5), (10,6)], orientation = none, motion = none}
car5565 = Entity {noun = "car ", position = (5,5), footprint = [(5,5), (6,5)], orientation = right, motion = none}
room6575 = Entity {noun = "room ", position = (6,5), footprint = [(6,5), (7,5)], orientation = none, motion = none}
country6575 = Entity {noun = "country ", position = (6,5), footprint = [(6,5), (7,5)], orientation = forward, motion = none}
town75 = Entity {noun = "town ", position = (7,5), footprint = [(7,5)], orientation = none, motion = none}
wheel93 = Entity {noun = "wheel ", position = (9,3), footprint = [(9,3)], orientation = forward, motion = forward}
river7595 = Entity {noun = "river ", position = (7,5), footprint = [(7,5),(8,5),(9,5)], orientation = right, motion = none}
peter95 = Entity {noun = "peter ", position = (9,5), footprint = [(9,5)], orientation = none, motion = none}
mary75 = Entity {noun = "mary ", position = (7,5), footprint = [(7,5)], orientation = none, motion = none}
queue7595 = Entity {noun = "queue ", position = (7,5), footprint = [(7,5),(8,5),(9,5)], orientation = right, motion = none}


----------------------------------------------------------------------
-- situations
-- fill spatial and discourse roles with entities and their aspects
-- examples are taken from COSIT 2011 submission and numbered accordingly
-- note that s1 to s13 (and possibly later) do NOT need the knowledge about the origin to compute the direction - what follows from this?
-- participants are only the relevant entities that have no other role 

data Situation = Situation {locatum :: !Entity,
							relatum :: !Entity,
							perspective :: !Direction,
							origin :: Position,
							speaker :: !Entity,
							addressee :: !Entity,
							participants :: [Entity]} deriving (Eq, Show)

s1 = Situation {locatum = box75, relatum = person55, perspective = orientation person55, origin = position person55, speaker = person55, addressee = external, participants = []}
-- locatum = participant, relatum = speaker, origin = speaker 311
s2 = Situation {locatum = box75, relatum = person55, perspective = orientation person55, origin = position person55, speaker = external, addressee = person55, participants = []}
-- locatum = participant, relatum = addressee, origin = addressee 322
s3 = Situation {locatum = box75, relatum = chair55, perspective = orientation chair55, origin = position chair55, speaker = external, addressee = external, participants = []}
-- relatum = participant, origin = participant 333
s4 = Situation {locatum = person75, relatum = person55, perspective = orientation person55, origin = position person55, speaker = person75, addressee = person55, participants = []}
-- locatum = speaker, relatum = addressee 122
s5 = Situation {locatum = person75, relatum = person55, perspective = orientation person55, origin = position person55, speaker = person55, addressee = person75, participants = []}
-- locatum = addressee, relatum = speaker 211
s6 = Situation {locatum = box73, relatum = ball75, perspective = orientation person55, origin = position person55, speaker = person55, addressee = external, participants = []}
-- relatum = participant, origin = speaker 331
s7 = Situation {locatum = box73, relatum = ball75, perspective = orientation person55, origin = position person55, speaker = person75, addressee = person55, participants = []}
-- relatum = participant, origin = addressee 332
s8 = Situation {locatum = box73, relatum = ball75, perspective = orientation chair55, origin = position chair55, speaker = external, addressee = external, participants = []}
-- origin = participant 333
s9 = Situation {locatum = person73, relatum = ball75, perspective = orientation person55, origin = position person55, speaker = person73, addressee = person55, participants = []}
-- locatum = speaker, relatum = participant, origin = addressee 132
s10 = Situation {locatum = person73, relatum = ball75, perspective = orientation person55, origin = position person55, speaker = person55, addressee = person73, participants = []}
-- locatum = addressee, relatum = participant, origin = speaker 231
s11 = Situation {locatum = box73, relatum = person75, perspective = orientation person55, origin = position person55, speaker = person75, addressee = person55, participants = []}
-- locatum = participant, relatum = speaker, origin = addressee 312
s12 = Situation {locatum = box73, relatum = person75, perspective = orientation person55, origin = position person55, speaker = person55, addressee = person75, participants = []}
-- locatum = participant, relatum = addressee, origin = speaker 321
s13a = Situation {locatum = box65, relatum = ball75, perspective = invert (orientation person55), origin = position person55, speaker = person55, addressee = external, participants = []}
-- locatum = participant, relatum = participant, origin = speaker 331
s13b = Situation {locatum = box95, relatum = ball75, perspective = orientation person55, origin = position person55, speaker = person55, addressee = external, participants = []}
-- locatum = participant, relatum = participant, origin = speaker 331
s14 = Situation {locatum = box95, relatum = ball75, perspective = none, origin = outside, speaker = external, addressee = external, participants = []}
-- locatum = participant, relatum = participant 330
--s15 = Situation {locatum = box95, relatum = ball2wall, perspective = none, origin = position ball75, speaker = external, addressee = external, participants = [wall105]}
-- locatum = participant, relatum = participant 330
s16 = Situation {locatum = box75, relatum = car5565, perspective = orientation car5565, origin = position car5565, speaker = external, addressee = external, participants = []}
-- locatum = participant, relatum = participant, origin = participant 333
s17 = Situation {locatum = box65, relatum = car5565, perspective = orientation car5565, origin = position car5565, speaker = external, addressee = external, participants = []}
-- locatum = participant, relatum = participant, origin = participant 333
s18 = Situation {locatum = box75, relatum = room6575, perspective = invert (orientation person55), origin = position person55, speaker = person55, addressee = external, participants = []}
-- locatum = participant, relatum = participant, origin = speaker 331
s20 = Situation {locatum = town75, relatum = country6575, perspective = none, origin = outside, speaker = external, addressee = external, participants = []}
-- locatum = participant, relatum = participant 330
-- s22 is a 3d case, not treated
s23 = Situation {locatum = box95, relatum = ball75, perspective = motion wheel93, origin = outside, speaker = external, addressee = external, participants = []}
-- locatum = participant, relatum = participant, origin = participant 333
s24 = Situation {locatum = box95, relatum = ball75, perspective = orientation river7595, origin = position ball75, speaker = external, addressee = external, participants = []}
s25 = Situation {locatum = peter95, relatum = mary75, perspective = orientation queue7595, origin = position mary75, speaker = external, addressee = external, participants = []}

----------------------------------------------------------------------
-- analysis
-- functions to analyze situations

-- the direction from relatum to locatum 
direction :: Situation -> Direction
direction s = fromTo (position (relatum s)) (position (locatum s))

-- the direction seen from the perspective
relativeDirection :: Situation -> Direction
relativeDirection s = if (absolute s) || (direction s == none) then direction s else (relativeTo (direction s) (perspective s))

-- the labels for reference frames
absolute, intrinsic, internal, static :: Situation -> Bool 
absolute s = (perspective s == none)
intrinsic s = (perspective s == orientation (relatum s)) 
internal s = ((position (locatum s)) `elem` (footprint (relatum s))) 
static s = (motion (locatum s) == none) && (motion (relatum s) == none)


----------------------------------------------------------------------
-- sentences
-- generating English sentences from situations

-- the subject and verb 
-- in field or object view
subject :: Situation -> View -> String 
subject s v = if speaker s == locatum s 
				then if v == Object then "I am " else "There is me "
				else if addressee s == locatum s 	
						then if v == Object then "You are " else "There is you "
						else if v == Object then "The " ++ noun (locatum s) ++ "is " else "There is a " ++ noun (locatum s)

-- the predicate 
-- naming the region in a given direction 
-- intrinsic and relative use the same expressions!
predicate :: Direction -> Situation -> String 

predicate (0,1) s = if (absolute s) then if (internal s) then "in the north of " else "north of "
									else if (internal s) then "in the front of " else "in front of " 
predicate (1,0) s = if (absolute s) then if (internal s) then "in the east of " else "east of "
									else if (internal s) then "on the right side of " else "to the right of "
predicate (0,-1) s = if (absolute s) then if (internal s) then "in the south of " else "south of " 
									else if (internal s) then "in the back of " else "behind "
predicate (-1,0) s = if (absolute s) then if (internal s) then "in the west of " else "west of " 
									else if (internal s) then "on the left side of " else "to the left of "

-- the object
object :: Situation -> String 
object s = if (speaker s) == (relatum s) then "me" else if (addressee s == relatum s) then "you" else "the " ++ noun (relatum s)  

describe :: Situation -> View -> String
describe s v =  subject s v ++ predicate (relativeDirection s) s ++ object s