2003/10/29 03:09:11

[org.ibex.core.git] / src / org / xwt / js / JS.java

diff --git a/src/org/xwt/js/JS.java b/src/org/xwt/js/JS.java
index ea12dfb..885d840 100644 (file)
--- a/src/org/xwt/js/JS.java
+++ b/src/org/xwt/js/JS.java
@@ -51,8 +51,9 @@ public abstract class JS {
     public static Number toNumber(Object o) {
         if (o == null) return new Long(0);
         if (o instanceof Number) return ((Number)o);
-        // FIXME: There are about 3 pages of rules in ecma262 about string to number conversions
-        // We aren't even close to following all those rules
+
+        // NOTE: There are about 3 pages of rules in ecma262 about string to number conversions
+        //       We aren't even close to following all those rules.  We probably never will be.
         if (o instanceof String) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(Double.NaN); }
         if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
         if (o instanceof JS) return ((JS)o).coerceToNumber();
@@ -155,6 +156,43 @@ public abstract class JS {
         public void declare(String s) { super.declare(s); }
     } 
 
+    /** the result of a graft */
+    public static class Graft extends JS {
+        private JS graftee;
+        private Object replaced_key;
+        private Object replaced_val;
+        public Graft(JS graftee, Object key, Object val) {
+            if (graftee instanceof Array) throw new JS.Exn("can't graft onto Arrays (yet)");
+            if (graftee instanceof Callable) throw new JS.Exn("can't graft onto Callables (yet)");
+            if (graftee instanceof Scope) throw new JS.Exn("can't graft onto Scopes (yet)");
+            this.graftee = graftee;
+            replaced_key = key;
+            replaced_val = val;
+        }
+        public boolean equals(Object o) { return (this == o || graftee.equals(o)); }
+        public int hashCode() { return graftee.hashCode(); }
+        public Object get(Object key) { return replaced_key.equals(key) ? replaced_val : graftee.get(key); }
+        public void put(Object key, Object val) { graftee.put(key, val); }
+        public Object callMethod(Object method, Array args, boolean checkOnly) throws JS.Exn {
+            if (!replaced_key.equals(method)) return graftee.callMethod(method, args, checkOnly);
+            if (replaced_val instanceof Callable) return checkOnly ? Boolean.TRUE : ((Callable)replaced_val).call(args);
+            if (checkOnly) return Boolean.FALSE;
+            throw new JS.Exn("attempt to call non-function");
+        }
+        public Number coerceToNumber() { return graftee.coerceToNumber(); }
+        public String coerceToString() { return graftee.coerceToString(); }
+        public boolean coerceToBoolean() { return graftee.coerceToBoolean(); }
+        public String typeName() { return graftee.typeName(); }
+        public Object[] keys() {
+            Object[] ret = graftee.keys();
+            for(int i=0; i<ret.length; i++) if (replaced_key.equals(ret[i])) return ret;
+            Object[] ret2 = new Object[ret.length + 1];
+            System.arraycopy(ret, 0, ret2, 0, ret.length);
+            ret2[ret2.length - 1] = replaced_key;
+            return ret2;
+        }
+    }
+
     /** anything that is callable with the () operator */
     public static abstract class Callable extends JS.Obj {
         public abstract Object call(JS.Array args) throws JS.Exn;