Setting Scope for Evaluation

Is it possible to set a scope containing all variables for evaluation? Something like this:

Map<String, BigDecimal> scope = new HashMap<>(); // contains values for a and b
scope.put("a", BigDecimal.ZERO);
scope.put("b", BigDecimal.ONE);
Expression ex = new Expression("a+b");
ex.eval(scope);

It would be nice if this wouldn’t mutate the internal state of ex, so the expression can be used across multiple threads.

[RobertZenz]

Just to make it clear, I have no problem with you rejecting any of my changes (especially ones that I started working on without waiting for your reply first).

My thought behind this was that parsing the expression might be something expensive that one only wants to do once and then use that Expression instance to run on different values (even on different threads). That is my idea behind this, but I understand what you mean.

You are right, we could move all these properties into the Scope, but I wouldn’t have done that. It is unlikely that you want to evaluate the same expression with different precisions, but what one might like to do is evaluate it with different values. Reusing Expressions would also become a lot more explicit (because currently one can only overwrite already added variables) and that the Expression can be used over multiple threads with ease is a nice feature to have, in my opinion, that is why I wanted to do this at all.

[nikeee]

Thats what I felt like, too. So I developed a more or less replacement for EvalEx that covers our use-case. I can post it here when I’ve got some spare time.