The grammar used for the Happy parser generator.

CGIFFile: CG
	| CG '.' CGIFFile

CG	: Node  
	| Node CG 

Node    : Relation 
       	| Concept
	| Actor
	| Negation

Relation: '(' TypeExp Arcs ')'

Actor	: '<' id Arcs '|' Arcs '>'

Negation: '~' '[' CG ']'

Arcs	: Arc
	| Arc Arcs

Arc	: Concept
	| '?' id

Concept	: '[' TypeExp ':' Referent ']'	
	| '[' TypeExp '*' id ':' Referent ']'
	| '[' TypeExp ']'			
	| '[' TypeExp '*' id ']'		
	| '[' ']'
	| '[' ':' Referent ']'

TypeExp	: id
	| '(' lambda '(' Params ')' CG ')'

Param	: id
	| id def

Params	: Param
	| Params ',' Param 

Referent: Literal
	| Quantifier
	| CG
	| Literal CG
	| Quantifier CG

Collection: '[' Literals ']'
	  | '\{' Literals '\}'
	  | '(' Literals ')'
	  | '<' Literals '>'

Literals: '*'
	 | Literal
	 | Literal ',' Literals

Literal	: string
	| '\'' id '\''			
	| '#' int
	| '#' id
	| Collection

Quantifier: '@' int
	  | '@' id

id is a character string
int is an integer
lambda is the string "lambda"