* object.c (rb_obj_ivar_defined, rb_mod_cvar_defined): new methods,

Kernel#instance_variable_defined? and Module#class_variable_defined?.
  [ruby-dev:29587]

* lib/date/format.rb (Date::Bag#method_missing): use new method,
  instance_variable_defined? to check if an instance variable is
  defined.  fixed: [ruby-dev:29554]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@10962 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/date/format.rb

@@ -98,10 +98,8 @@ class Date
 	t = '@' + t
 	if set
 	  instance_variable_set(t, *args)
-	else
+	elsif instance_variable_defined?(t)
-	  if instance_variables.include?(t)
+	  instance_variable_get(t)
-	    instance_variable_get(t)
-	  end
 	end
       end
 

object.c

@@ -1839,7 +1839,6 @@ rb_mod_const_defined(mod, name)
  *     k.methods.length   #=> 42
  */
 
-
 static VALUE
 rb_obj_methods(argc, argv, obj)
     int argc;
@@ -1967,7 +1966,6 @@ rb_obj_ivar_get(obj, iv)
     return rb_ivar_get(obj, id);
 }
 
-
 /*
  *  call-seq:
  *     obj.instance_variable_set(symbol, obj)    => obj
@@ -2000,6 +1998,36 @@ rb_obj_ivar_set(obj, iv, val)
     return rb_ivar_set(obj, id, val);
 }
 
+/*
+ *  call-seq:
+ *     obj.instance_variable_defined?(symbol)    => true or false
+ *
+ *  Returns <code>true</code> if the given instance variable is
+ *  defined in <i>obj</i>.
+ *
+ *     class Fred
+ *       def initialize(p1, p2)
+ *         @a, @b = p1, p2
+ *       end
+ *     end
+ *     fred = Fred.new('cat', 99)
+ *     fred.instance_variable_defined?(:@a)    #=> true
+ *     fred.instance_variable_defined?("@b")   #=> true
+ *     fred.instance_variable_defined?("@c")   #=> false
+ */
+
+static VALUE
+rb_obj_ivar_defined(obj, iv)
+    VALUE obj, iv;
+{
+    ID id = rb_to_id(iv);
+
+    if (!rb_is_instance_id(id)) {
+	rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
+    }
+    return rb_ivar_defined(obj, id);
+}
+
 /*
  *  call-seq:
  *     mod.class_variable_get(symbol)    => obj
@@ -2029,7 +2057,6 @@ rb_mod_cvar_get(obj, iv)
     return rb_cvar_get(obj, id);
 }
 
-
 /*
  *  call-seq:
  *     obj.class_variable_set(symbol, obj)    => obj
@@ -2064,6 +2091,32 @@ rb_mod_cvar_set(obj, iv, val)
     return val;
 }
 
+/*
+ *  call-seq:
+ *     obj.class_variable_defined?(symbol)    => true or false
+ *
+ *  Returns <code>true</code> if the given class variable is defined
+ *  in <i>obj</i>.
+ *
+ *     class Fred
+ *       @@foo = 99
+ *     end
+ *     Fred.class_variable_defined?(:@@foo)    #=> true
+ *     Fred.class_variable_defined?(:@@bar)    #=> false
+ */
+
+static VALUE
+rb_mod_cvar_defined(obj, iv)
+    VALUE obj, iv;
+{
+    ID id = rb_to_id(iv);
+
+    if (!rb_is_instance_id(id)) {
+	rb_name_error(id, "`%s' is not allowed as an instance variable name", rb_id2name(id));
+    }
+    return rb_cvar_defined(obj, id);
+}
+
 static VALUE
 convert_type(val, tname, method, raise)
     VALUE val;
@@ -2604,6 +2657,7 @@ Init_Object()
 		     rb_obj_instance_variables, 0); /* in variable.c */
     rb_define_method(rb_mKernel, "instance_variable_get", rb_obj_ivar_get, 1);
     rb_define_method(rb_mKernel, "instance_variable_set", rb_obj_ivar_set, 2);
+    rb_define_method(rb_mKernel, "instance_variable_defined?", rb_obj_ivar_defined, 1);
     rb_define_private_method(rb_mKernel, "remove_instance_variable",
 			     rb_obj_remove_instance_variable, 1); /* in variable.c */
 
@@ -2685,6 +2739,7 @@ Init_Object()
     rb_define_method(rb_cModule, "private_instance_methods", 
 		     rb_class_private_instance_methods, -1);   /* in class.c */
 
+    rb_define_method(rb_cModule, "class_variable_defined?", rb_mod_cvar_defined, 1);
     rb_define_method(rb_cModule, "constants", rb_mod_constants, 0); /* in variable.c */
     rb_define_method(rb_cModule, "const_get", rb_mod_const_get, 1);
     rb_define_method(rb_cModule, "const_set", rb_mod_const_set, 2);