A simple expression evaluator for JSQLParser

EvalLib consists of one abstract class: net.sf.jsqlparser.eval.Eval that implements nearly all of EvalLib's functionality.
To complete EvalLib, you need to add a method to assign values to variables (i.e., you need to define a scope lookup function). The abstract method eval takes a JSQLParser Column as input and must return a PrimitiveValue subclass. There are two suggested ways of doing this: (1) Instantiate an Eval instance inline whenever you get a new scope, or (2) subclass Eval.

For example:

  Map<String,PrimitiveValue> scope = /* ... */;
  Eval eval = new Eval() { 
    public PrimitiveValue eval(Column col){
      String name = col.getColumnName();
      if(col.getTable() != null && col.getTable().getName() != null){
        name = col.getTable().getName() + "." + col
      }
      return scope.get(name);
    }
  }

Call eval.eval(). For example:

result =
    eval.eval(
      new GreaterThanEquals(
        new Column(new Table(null, "R"), "A"), // `R.A`
        new LongPrimitive(5)
      )
    );