activity.treetop

grammar ActivityDiagram	

        rule diagram
	  phrase 
	end
	
	rule phrase
	        node  (connector node)* 		
	end
		
	rule node
		activity / parallel / decision
	end
	
	rule activity
		'(' label:[a-zA-Z]+ ')'		
	end	
	
	rule parallel
		'|' label:[a-zA-Z]+ '|'
	end
	
	rule decision
		'<' label:[a-zA-Z]+ '>'
	end
	
	rule connector
		(left_arrow)? (left_label)? '-' (right_label)? (right_arrow)?
	end
	
	rule left_arrow
		'<'
	end
	
	rule right_arrow
		'>'
	end
	
	rule left_label
		line_label
	end
	
	rule right_label
		line_label	
	end
	
	rule line_label
		[a-zA-Z_0-9]+
	end
	
	rule comma
		','
	end
end