Look for non existing terminals in precedence rules

src/inputparser.cpp

@@ -72,6 +72,13 @@ namespace pds {
             else rule->precedence = {false,{0, PrecedenceType::RIGHT}};
         }
 
+		// Check if all terminals in precedence rules, are terminals
+		for(auto& prec : cnf.grammar.precedence) 
+
+			if (cnf.grammar.terminals.find(prec.first) == cnf.grammar.terminals.end())
+				throw InputParserException("Found \"" + prec.first + "\" in precedence, which is no terminal.");
+			
+
         return cnf;
     }   
 }