QUERY: CREATE TABLE PATH_TBL (f1 path);
QUERY: INSERT INTO PATH_TBL VALUES ('[(1,2),(3,4)]');
QUERY: INSERT INTO PATH_TBL VALUES ('((1,2),(3,4))');
QUERY: INSERT INTO PATH_TBL VALUES ('[(0,0),(3,0),(4,5),(1,6)]');
QUERY: INSERT INTO PATH_TBL VALUES ('((1,2),(3,4))');
QUERY: INSERT INTO PATH_TBL VALUES ('1,2 ,3,4');
QUERY: INSERT INTO PATH_TBL VALUES ('[1,2,3, 4]');
QUERY: INSERT INTO PATH_TBL VALUES ('[11,12,13,14]');
QUERY: INSERT INTO PATH_TBL VALUES ('(11,12,13,14)');
QUERY: INSERT INTO PATH_TBL VALUES ('[(,2),(3,4)]');
WARN:Bad path external representation '[(,2),(3,4)]'
QUERY: INSERT INTO PATH_TBL VALUES ('[(1,2),(3,4)');
WARN:Bad path external representation '[(1,2),(3,4)'
QUERY: SELECT f1 FROM PATH_TBL;
f1                       
-------------------------
[(1,2),(3,4)]            
((1,2),(3,4))            
[(0,0),(3,0),(4,5),(1,6)]
((1,2),(3,4))            
((1,2),(3,4))            
[(1,2),(3,4)]            
[(11,12),(13,14)]        
((11,12),(13,14))        
(8 rows)

QUERY: SELECT '' AS count, f1 AS open_path FROM PATH_TBL WHERE isopen(f1);
count|open_path                
-----+-------------------------
     |[(1,2),(3,4)]            
     |[(0,0),(3,0),(4,5),(1,6)]
     |[(1,2),(3,4)]            
     |[(11,12),(13,14)]        
(4 rows)

QUERY: SELECT '' AS count, f1 AS closed_path FROM PATH_TBL WHERE isclosed(f1);
count|closed_path      
-----+-----------------
     |((1,2),(3,4))    
     |((1,2),(3,4))    
     |((1,2),(3,4))    
     |((11,12),(13,14))
(4 rows)

QUERY: SELECT '' AS count, pclose(f1) AS closed_path FROM PATH_TBL;
count|closed_path              
-----+-------------------------
     |((1,2),(3,4))            
     |((1,2),(3,4))            
     |((0,0),(3,0),(4,5),(1,6))
     |((1,2),(3,4))            
     |((1,2),(3,4))            
     |((1,2),(3,4))            
     |((11,12),(13,14))        
     |((11,12),(13,14))        
(8 rows)

QUERY: SELECT '' AS count, popen(f1) AS open_path FROM PATH_TBL;
count|open_path                
-----+-------------------------
     |[(1,2),(3,4)]            
     |[(1,2),(3,4)]            
     |[(0,0),(3,0),(4,5),(1,6)]
     |[(1,2),(3,4)]            
     |[(1,2),(3,4)]            
     |[(1,2),(3,4)]            
     |[(11,12),(13,14)]        
     |[(11,12),(13,14)]        
(8 rows)