[ruby-talk:19575] Re: Perl/Python/Ruby common backend (Parrot, can Ruby play too?)

On Fri, 10 Aug 2001, Ned Konz wrote:

> could load on demand. However, when I re-load an object that I had a proxy 
> to, I want all the other objects that pointed to the proxy to now point to 
> the real object.
> Being able to swap their identities allows me to do this.
> This is a trivial operation on the old Smalltalks that used double 
> indirection to get to objects.



Patch below.



----------------8<----------------cut-here----------------8<----------------
diff -u -u -r1.51 object.c
--- object.c    2001/05/30 09:12:34     1.51
+++ object.c    2001/08/12 05:51:57
@@ -33,6 +33,20 @@
 static ID inspect;
 static ID clone;
 
+VALUE rb_obj_become(VALUE self, VALUE other) {
+       long t[5];
+       if (IMMEDIATE_P(self))
+               rb_raise(rb_eTypeError, "%s is not boxed",
+                       rb_class2name(CLASS_OF(self)));
+       if (IMMEDIATE_P(other))
+               rb_raise(rb_eTypeError, "%s is not boxed",
+                       rb_class2name(CLASS_OF(other)));
+       memcpy((long *)t    ,(long *)self ,5*sizeof(long));
+       memcpy((long *)self ,(long *)other,5*sizeof(long));
+       memcpy((long *)other,(long *)t    ,5*sizeof(long));
+       return self;
+}
+
 VALUE
 rb_equal(obj1, obj2)
     VALUE obj1, obj2;
@@ -1296,4 +1310,6 @@
     eql = rb_intern("eql?");
     inspect = rb_intern("inspect");
     clone = rb_intern("clone");
+
+    rb_define_method(rb_mKernel, "become", rb_obj_become, 1);
 }
----------------8<--------------d馗oupez-ici--------------8<----------------

a = [6,6,6]
b = {42,13}
p a        #=> [6, 6, 6]
p b        #=> {42=>13}
a.become b
p a        #=> {42=>13}
p b        #=> [6, 6, 6]
a.become b
p a        #=> [6, 6, 6]
p b        #=> {42=>13}

----------------8<--------------d馗oupez-ici--------------8<----------------

matju