* linked list stack, with the most recently placed trap at the head
* of the list.
*/
-class Trap {
+final class Trap {
- JS trapee = null; ///< the box on which this trap was placed
- Object name = null; ///< the property that the trap was placed on
+ final JS target; ///< the box on which this trap was placed
+ final JS key; ///< the property that the trap was placed on
- JSFunction f = null; ///< the function for this trap
- Trap next = null; ///< the next trap down the trap stack
+ final JSFunction f; ///< the function for this trap
+ Trap next; ///< the next trap down the trap stack
- Trap(JS b, String n, JSFunction f, Trap nx) {
- trapee = b; name = n; this.f = f; this.next = nx;
- }
-
- private static final JSFunction putInvoker = new JSFunction("putInvoker", 0, null);
- private static final JSFunction getInvoker = new JSFunction("getInvoker", 0, null);
-
- static {
- putInvoker.add(1, ByteCodes.PUT, null);
- putInvoker.add(2, Tokens.RETURN, null);
- getInvoker.add(1, ByteCodes.GET, null);
- getInvoker.add(2, Tokens.RETURN, null);
+ Trap(JS b, JS n, JSFunction f, Trap nx) {
+ target = b; key = n; this.f = f; this.next = nx;
}
- void invoke(Object value) throws JSExn {
- Interpreter i = new Interpreter(putInvoker, false, null);
- i.stack.push(trapee);
- i.stack.push(name);
- i.stack.push(value);
- i.resume();
- }
-
- Object invoke() throws JSExn {
- Interpreter i = new Interpreter(getInvoker, false, null);
- i.stack.push(trapee);
- i.stack.push(name);
- return i.resume();
- }
-
- // FIXME: review; is necessary?
- static class TrapScope extends JSScope {
- Trap t;
- Object val = null;
- boolean cascadeHappened = false;
- public TrapScope(JSScope parent, Trap t, Object val) { super(parent); this.t = t; this.val = val; }
- public Object get(Object key) throws JSExn {
- if (key.equals("trapee")) return t.trapee;
- if (key.equals("callee")) return t.f;
- if (key.equals("trapname")) return t.name;
- return super.get(key);
- }
- }
+ boolean isReadTrap() { return f.numFormalArgs == 0; }
+ boolean isWriteTrap() { return f.numFormalArgs != 0; }
+ Trap readTrap() { Trap t = this; while(t!=null && t.isWriteTrap()) t = t.next; return t; }
+ Trap writeTrap() { Trap t = this; while(t!=null && t.isReadTrap()) t = t.next; return t; }
+ Trap nextReadTrap() { return next == null ? null : next.readTrap(); }
+ Trap nextWriteTrap() { return next == null ? null : next.writeTrap(); }
}
-