allow lambda duplication

src/proc.c

@@ -56,20 +56,40 @@ mrb_proc_new_cfunc(mrb_state *mrb, mrb_func_t func)
   return p;
 }
 
+static inline void
+proc_copy(struct RProc *a, struct RProc *b)
+{
+  a->body = b->body;
+  a->target_class = b->target_class;
+  a->env = b->env;
+}
+
 static mrb_value
 mrb_proc_initialize(mrb_state *mrb, mrb_value self)
 {
   mrb_value blk;
 
   mrb_get_args(mrb, "&", &blk);
-  if (!mrb_nil_p(blk)) {
-    *mrb_proc_ptr(self) = *mrb_proc_ptr(blk);
-  }
-  else {
+  if (mrb_nil_p(blk)) {
     /* Calling Proc.new without a block is not implemented yet */
     mrb_raise(mrb, E_ARGUMENT_ERROR, "tried to create Proc object without a block");
   }
+  else {
+    proc_copy(mrb_proc_ptr(self), mrb_proc_ptr(blk));
+  }
+  return self;
+}
+
+static mrb_value
+mrb_proc_init_copy(mrb_state *mrb, mrb_value self)
+{
+  mrb_value proc;
 
+  mrb_get_args(mrb, "o", &proc);
+  if (mrb_type(proc) != MRB_TT_PROC) {
+    mrb_raise(mrb, E_ARGUMENT_ERROR, "not a proc");
+  }
+  proc_copy(mrb_proc_ptr(self), mrb_proc_ptr(proc));
   return self;
 }
 
@@ -108,8 +128,10 @@ mrb_init_proc(mrb_state *mrb)
   call_irep->ilen = 1;
 
   mrb->proc_class = mrb_define_class(mrb, "Proc", mrb->object_class);
+  MRB_SET_INSTANCE_TT(mrb->proc_class, MRB_TT_PROC);
 
   mrb_define_method(mrb, mrb->proc_class, "initialize", mrb_proc_initialize, ARGS_NONE());
+  mrb_define_method(mrb, mrb->proc_class, "initialize_copy", mrb_proc_init_copy, ARGS_REQ(1));
 
   m = mrb_proc_new(mrb, call_irep);
   mrb_define_method_raw(mrb, mrb->proc_class, mrb_intern(mrb, "call"), m);