* lib/pp.rb (PP::ObjectMixin#pretty_print): refine to_s handling.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@3779 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Sun May 11 05:50:39 2003  Tanaka Akira  <akr@m17n.org>
+
+        * lib/pp.rb (PP::ObjectMixin#pretty_print): refine to_s handling.
+
 Sat May 10 19:00:08 2003  Takaaki Uematsu  <uema2x@jcom.home.ne.jp>
 
 	* wince/string.c: file removed.

lib/pp.rb

@@ -239,13 +239,15 @@ class PP < PrettyPrint
 
   module ObjectMixin
     # 1. specific pretty_print
-    # 2. specific inspect or to_s
-    # 3. generic pretty_print
+    # 2. specific inspect
+    # 3. specific to_s if instance variable is empty
+    # 4. generic pretty_print
 
     def pretty_print(pp)
-      if /\(Kernel\)#/ !~ method(:inspect).inspect ||
-         /\(Kernel\)#/ !~ method(:to_s).inspect
-        pp.text inspect
+      if /\(Kernel\)#/ !~ method(:inspect).inspect
+        pp.text self.inspect
+      elsif /\(Kernel\)#/ !~ method(:to_s).inspect && instance_variables.empty?
+        pp.text self.to_s
       else
         pp.pp_object(self)
       end
@@ -521,6 +523,23 @@ if __FILE__ == $0
       a = proc {1}
       assert_equal("#{a.inspect}\n", PP.pp(a, ''))
     end
+
+    class Test_to_s_with_iv
+      def initialize() @a = nil end
+      def to_s() "aaa" end
+    end
+    def test_to_s_with_iv
+      a = Test_to_s_with_iv.new
+      assert_equal("#{a.inspect}\n", PP.pp(a, ''))
+    end
+    
+    class Test_to_s_without_iv
+      def to_s() "aaa" end
+    end
+    def test_to_s_without_iv
+      a = Test_to_s_without_iv.new
+      assert_equal("#{a.inspect}\n", PP.pp(a, ''))
+    end
   end
 
   class PPCycleTest < Test::Unit::TestCase