code: public Object eval(Bindings bindings, String expression) throws ScriptException {
      CompiledScript compiledExpression = requireNonNull(expressions.get(expression));
      Object returnValue = compiledExpression.eval(bindings);
      return convertNashornValue(returnValue);
    }
docs: Evaluates an expression using the given bindings.
  
  @param bindings the Bindings to use as ENGINE_SCOPE
  @param expression the expression to evaluate
  @return result of the evaluation
  @throws ScriptException if the evaluation fails