// represents a JavaX expression that can both
// -be evaluated right now (quickEval())
// -be transformed into Java source code (str())
//
// A is the expression's return type.

sinterface ICachedJavaXExpr<A> extends IMeta {
  // override to provide an evaluation result
  public default A quickEval() { fail("Can't quick eval: " + toStringWithClassName(this)); }
  
  public default IJavaXExpr<A> unpack() { this; }
  
  // overridable
  default int sourceCodeLength() { ret l(toString()); }
}