Context-free grammar of the accident formalism


This appendix contains the description of the accident description formalism, 
in the form of a CFG (Chomsky Formal Grammar). 

1 Definition of the general formalism 

form 			=>	staticPart dynamicPart accidentPart 
staticPart		=>	STATIC leftBracket staticObjectList rightBracket 
staticObjectList 	=> 	staticObject | (staticObject staticObjectList) 
dynamicPart 		=> 	DYNAMIC leftbracket dynamicObjectList rightBracket 
dynamicObjectList	=>	dynamicObject | (dynamicObject dynamicObjectList) 
accidentPart 		=> 	ACCIDENT leftBracket collisionObjectList rightBracket 
collisionObjectList 	=> 	collisionPart | (collisionPart collisionObjectList) 

2 Definition of terminals and general grammar rules 

equals 		=> 	'=' 
semicolon 	=> 	';' 
separator 	=> 	',' 
leftBracket 	=> 	'[' 
rightBracket 	=> 	']' 
openBracket 	=> 	'(' 
closeBracket 	=> 	')' 
id 		=> 	ID equals <string> semicolon 
coords 		=> 	COORD equals openBracket <number> separator <number>
closeBracket semicolon 
 

3 Definition of static objects 

staticObject 		=> 	roadObject | treeObject | traOEcLightObject | levelCrossing 
| stopSign 
roadObject 		=> 	ROAD leftbracket roadProperties rightBracket 
roadProperties 	=> 	KIND equals ( crossroad | straightroad | turn_left 
| turn_right ) semicolon 
treeObject 		=> 	TREE leftBracket treeProperties rightBracket 
treeProperties 		=> 	id coords 
trafficLightObject 	=> 	LIGHT leftBracket lightProperties rightBracket 
lightProperties 	=> 	id colorType coords 
colorType 		=> 	COLOR equals (red | orange | green | inactive) semicolon 
levelCrossing 		=> 	CROSSING leftBracket coords rightBracket 
stopSign 		=> 	STOPSIGN leftBracket coords rightBracket 

4 Definition of dynamic objects 

dynamicObject 	=> 	VEHICLE leftBracket vehicleProperties rightBracket 
vehicleProperties 	=> 	id kind [initDir] [startsign] [endsign] [eventChain] 
kind 			=> 	KIND equals (car | truck) semicolon 
initDir 			=> 	INITDIRECTION equals (north | south | east | west) semicolon 
startsign 		=> 	STARTSIGN equals <string> semicolon 
endsign 		=> 	ENDSIGN equals <string> semicolon 
eventChain 		=> 	CHAIN leftBracket eventList rightBracket 
eventList 		=> 	((event | criticalEvent) eventList) | (event | criticalEvent) 
event 			=> 	EVENT leftBracket eventProperties rightBracket 
criticalEvent 		=> 	CRITICAL_EVENT leftBracket eventProperties rightBracket 
eventProperties 	=> 	eventKind 
eventKind 		=> 	KIND equals ( driving_forward | turn_left | turn_right | stop 
| overtake | change_lane_left | change_lane_right) semicolon 

5 Definition of collision objects 

collisionPart 		=> 	COLLISION leftBracket collisionDescription rightBracket 
collisionDescription 	=> 	actorDescription victimDescription [coords] 
actorDescription 	=> 	ACTOR equals <string> separator vehiclePart semicolon 
victimDescription 	=> 	VICTIM equals <string> separator vehiclePart semicolon 
vehiclePart 		=> 	(front | rear | leftside | rightside | unknown)