The use of brackets is now equal to that of parentheses.

src/parser.py

@@ -116,6 +116,7 @@ class Parser(BisonParser):
         ('left', ('MINUS', 'PLUS')),
         ('nonassoc', ('INTEGRAL', 'DERIVATIVE')),
         ('left', ('TIMES', )),
+        ('left', ('PRIME', )),
         ('left', ('DIVIDE', )),
         ('nonassoc', ('PRIME', )),
         ('nonassoc', ('NEG', )),