Major When user write computations with MVEL, mvel throw the error [Error: not a statement, or badly formed structure] at parsing time.
If you add parenthesis, parsing is OK.
The issue can be reproduced directly with the lastest MVEL version.
As you can see in the test below, same expression with parenthesis is OK. Debugging into mvel engine shows that there some nullPointerException in the bad case.
This issue was reproduced with the MVEL version embedded inside Drools 5.5.0Final and also with MVEL version 2.1.9.Final.
public class MvelTest { public void test(){ String expressionThatDoesNotWork = "5 + 1/10 * (VAR - 5)"; // !!! mvel cannot parse this expression String expressionThatWorks = "5 + (1/10) * (VAR - 5)"; //with additionnal parenthesis it's OK Serializable parsingResultOK = MVEL.compileExpression(expressionThatWorks); //this works seamlessly System.out.println(parsingResultOK); //=> (Literal<5> + (Literal<0.1> * (VAR - Literal<5>))) Serializable failedResult = MVEL.compileExpression(expressionThatDoesNotWork); // !!! this throws NullPointerException in MVEL engine } }
