check object type before retrieving instance variabls; close #311

1 files changed, 44 insertions, 0 deletions

diff --git a/src/variable.c b/src/variable.c
index 051c971d6..e785d56b7 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -185,6 +185,50 @@ mrb_vm_iv_set(mrb_state *mrb, mrb_sym sym, mrb_value v)
   mrb_iv_set(mrb, mrb->stack[0], sym, v);
 }
 
+/* 15.3.1.3.23 */
+/*
+ *  call-seq:
+ *     obj.instance_variables    -> array
+ *
+ *  Returns an array of instance variable names for the receiver. Note
+ *  that simply defining an accessor does not create the corresponding
+ *  instance variable.
+ *
+ *     class Fred
+ *       attr_accessor :a1
+ *       def initialize
+ *         @iv = 3
+ *       end
+ *     end
+ *     Fred.new.instance_variables   #=> [:@iv]
+ */
+mrb_value
+mrb_obj_instance_variables(mrb_state *mrb, mrb_value self)
+{
+  mrb_value ary;
+  kh_iv_t *h;
+  khint_t i;
+  int len;
+  const char* p;
+
+  ary = mrb_ary_new(mrb);
+  if (obj_iv_p(self)) {
+    h = ROBJECT_IVPTR(self);
+    if (h) {
+      for (i=0;i<kh_end(h);i++) {
+        if (kh_exist(h, i)) {
+          p = mrb_sym2name_len(mrb, kh_key(h,i), &len);
+          if (len > 1 && *p == '@') {
+            if (mrb_type(kh_value(h, i)) != MRB_TT_UNDEF)
+              mrb_ary_push(mrb, ary, mrb_str_new(mrb, p, len));
+          }
+        }
+      }
+    }
+  }
+  return ary;
+}
+
 mrb_value
 mrb_vm_cv_get(mrb_state *mrb, mrb_sym sym)
 {