diff --git a/src/debug.h b/src/debug.h
index 072e0fb..0a304d1 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -44,6 +44,6 @@ static void dump8(unsigned char* to_dump, unsigned long offset,
 }
 
 //
-#define TRACE(...) do { (void)printf(__FUNCTION__ ": "); (void)printf(__VA_ARGS__); } while(0)
+#define TRACE(...) do { printf(__VA_ARGS__); } while(0)
 
 #endif
diff --git a/src/main.cpp b/src/main.cpp
index 78ed2d0..6f4370a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -27,7 +27,7 @@ int main(int argc, char* argv[])
                 if (prog.run(s_global_stack, s_global_heap) == ret_good_bye)
                     break;
                 else
-                    program::show_stack(s_global_stack, false);
+                    program::show_stack(s_global_stack);
             }
         }
     }
@@ -53,7 +53,7 @@ int main(int argc, char* argv[])
 
             // run it
             ret = prog.run(s_global_stack, s_global_heap);
-            program::show_stack(s_global_stack);
+            program::show_stack(s_global_stack, true);
         }
     }
  
diff --git a/src/object.hpp b/src/object.hpp
index 15477a6..1757d83 100644
--- a/src/object.hpp
+++ b/src/object.hpp
@@ -161,7 +161,7 @@ struct number : public object
 
 struct ostring : public object
 {
-    //
+    // ostring may first have been allocated with len+1 bytes
     void set(const char* value, unsigned int len)
     {
         _type = cmd_string;
@@ -173,17 +173,20 @@ struct ostring : public object
             _len = len;
         }
         else
-            len = 0;
+        {
+            _value[_len] = 0;
+            _len = 0;
+        }
     }
 
-    //
+    // length of _value, not includiong the terminal '\0'
     unsigned int _len;
     char _value[0];
 };
 
 struct oprogram : public object
 {
-    //
+    // oprogram may first have been allocated with len+1 bytes
     void set(const char* value, unsigned int len)
     {
         _type = cmd_program;
@@ -195,17 +198,20 @@ struct oprogram : public object
             _len = len;
         }
         else
-            len = 0;
+        {
+            _value[0] = 0;
+            _len = 0;
+        }
     }
 
-    //
+    // length of _value, not includiong the terminal '\0'
     unsigned int _len;
     char _value[0];
 };
 
 struct symbol : public object
 {
-    //
+    // symbol may first have been allocated with len+1 bytes
     void set(const char* value, unsigned int len, bool auto_eval)
     {
         _type = cmd_symbol;
@@ -219,18 +225,22 @@ struct symbol : public object
             _len = len;
         }
         else
-            len = 0;
+        {
+            _value[0] = 0;
+            _len = 0;
+        }
     }
 
     //
     bool _auto_eval;
+    // length of _value, not includiong the terminal '\0'
     unsigned int _len;
     char _value[0];
 };
 
 struct keyword : public object
 {
-    //
+    // keyword may first have been allocated with len+1 bytes
     void set(program_fn_t fn, const char* value, unsigned int len)
     {
         _type = cmd_keyword;
@@ -243,11 +253,15 @@ struct keyword : public object
             _len = len;
         }
         else
-            len = 0;
+        {
+            _value[0] = 0;
+            _len = 0;
+        }
     }
 
     //
     program_fn_t _fn;
+    // length of _value, not includiong the terminal '\0'
     unsigned int _len;
     char _value[0];
 };
@@ -273,7 +287,10 @@ struct branch : public object
             _len = len;
         }
         else
-            len = 0;
+        {
+            _value[0] = 0;
+            _len = 0;
+        }
     }
 
     // branch function
@@ -282,6 +299,8 @@ struct branch : public object
     int arg1, arg2, arg3;
     number *farg1, *farg2;
     bool arg_bool;
+    
+    // length of _value, not includiong the terminal '\0'
     unsigned int _len;
     char _value[0];
 };
diff --git a/src/parse.hpp b/src/parse.hpp
index c2573ae..2337bf2 100644
--- a/src/parse.hpp
+++ b/src/parse.hpp
@@ -140,7 +140,7 @@ static bool _cut(const char* entry, vector<string>& entries)
                     tmp = "<< ";
 
                     // trim leading spaces
-                    while (i < len && (entry[i]==' ' || entry[i]=='\t'))
+                    while (i < len && isspace(entry[i]))
                         i++;
 
                     while(i < len)
@@ -149,20 +149,25 @@ static bool _cut(const char* entry, vector<string>& entries)
                         {
                             up++;
                             i += 2;
-                            tmp += " << ";
+                            tmp += "<< ";
                             // trim leading spaces
-                            while (i < len && (entry[i] == ' ' || entry[i] == '\t'))
+                            while (i < len && isspace(entry[i]))
                                 i++;
                         }
                         else if (strncmp(&entry[i], ">>", 2) == 0)
-                        {
+                        {                        
+                            if (isspace(entry[i-1]) && entry[i-2]!='>')
+                                tmp += ">>";
+                            else
+                                tmp += " >>";
+
                             up--;
                             i += 2;
-                            tmp += " >>";
 
                             // trim trailing spaces
-                            while (i < len && (entry[i] == ' ' || entry[i] == '\t'))
+                            while (i < len && isspace(entry[i]))
                                 i++;
+
                             // found end
                             if (up == 0)
                                 break;
@@ -174,9 +179,8 @@ static bool _cut(const char* entry, vector<string>& entries)
                         }
                     }
                     while((up--)>0)
-                    {
                         tmp += " >>";
-                    }
+
                     if (tmp.size()>0)
                     {
                         entries.push_back(tmp);
@@ -185,15 +189,13 @@ static bool _cut(const char* entry, vector<string>& entries)
                     i--;// i has move 1 too far
                 }
                 else
-                {
                     // reinject '<'' which is not a prog begin
                     tmp = "<";
-                }
                 break;
 
             //other
             default:
-                if (entry[i] != ' ' && entry[i] != '\t')
+                if (!isspace(entry[i]))
                 {
                     tmp += entry[i];
                 }
@@ -349,7 +351,7 @@ static bool get_string(const string& entry, program& prog, string& remaining_ent
     return ret;
 }
 
-static bool get_program(const string& entry, program& prog, string& remaining_entry)
+static bool get_program(string& entry, program& prog, string& remaining_entry)
 {
     bool ret = false;
     unsigned int obj_len;
@@ -412,7 +414,7 @@ static bool get_number(const string& entry, program& prog, string& remaining_ent
     return ret;
 }
 
-static bool _obj_from_string(const string& entry, program& prog, string& remaining_entry)
+static bool _obj_from_string(string& entry, program& prog, string& remaining_entry)
 {
     bool ret = false;
     
diff --git a/src/rpn-branch.hpp b/src/rpn-branch.hpp
index 2bee27c..4c46b08 100644
--- a/src/rpn-branch.hpp
+++ b/src/rpn-branch.hpp
@@ -105,7 +105,6 @@ int rpn_for(branch& myobj)
     {
         // store symbol with first value
         _local_heap.add(sym->_value, (object*)myobj.farg1, myobj.farg1->size());
-        (void)_stack->pop_back();
         ret = myobj.arg1 + 1;
     }
 
diff --git a/src/rpn-stack.hpp b/src/rpn-stack.hpp
index 1b20244..9c03034 100644
--- a/src/rpn-stack.hpp
+++ b/src/rpn-stack.hpp
@@ -6,11 +6,12 @@ void swap(void)
     stack::copy_and_push_back(*_stack, _stack->size()-2, _branch_stack);
     (void)_stack->pop_back();
     (void)_stack->pop_back();
-    stack::copy_and_push_back(_branch_stack, 0, *_stack);
-    stack::copy_and_push_back(_branch_stack, 1, *_stack);
-    _branch_stack.erase();
-}
+    stack::copy_and_push_back(_branch_stack, _branch_stack.size()-2, *_stack);
+    stack::copy_and_push_back(_branch_stack, _branch_stack.size()-1, *_stack);
+    _branch_stack.pop_back();
+    _branch_stack.pop_back();
 
+}
 void drop(void)
 {
     MIN_ARGUMENTS(1);
@@ -95,10 +96,12 @@ void rot(void)
     (void)_stack->pop_back();
     (void)_stack->pop_back();
     (void)_stack->pop_back();
-    stack::copy_and_push_back(_branch_stack, 1, *_stack);
-    stack::copy_and_push_back(_branch_stack, 2, *_stack);
-    stack::copy_and_push_back(_branch_stack, 0, *_stack);
-    _branch_stack.erase();
+    stack::copy_and_push_back(_branch_stack, _branch_stack.size()-2, *_stack);
+    stack::copy_and_push_back(_branch_stack, _branch_stack.size()-1, *_stack);
+    stack::copy_and_push_back(_branch_stack, _branch_stack.size()-3, *_stack);
+    _branch_stack.pop_back();
+    _branch_stack.pop_back();
+    _branch_stack.pop_back();
 }
 
 void depth(void)
@@ -127,7 +130,8 @@ void roll(void)
         stack::copy_and_push_back(_branch_stack, args-1-i, *_stack);
     stack::copy_and_push_back(_branch_stack, args-1, *_stack);
 
-    _branch_stack.erase();
+    for(int i=0;i<args;i++)
+        _branch_stack.pop_back();
 }
 
 void rolld(void)
@@ -145,11 +149,13 @@ void rolld(void)
         (void)_stack->pop_back();
     }
 
-    stack::copy_and_push_back(_branch_stack, 0, *_stack);
-    for(int i=1;i<args;i++)
-        stack::copy_and_push_back(_branch_stack, args-i, *_stack);
+    stack::copy_and_push_back(_branch_stack, _branch_stack.size()-args, *_stack);
 
-    _branch_stack.erase();
+    for(int i=1;i<args;i++)
+        stack::copy_and_push_back(_branch_stack, _branch_stack.size()-i, *_stack);
+
+    for(int i=0;i<args;i++)
+        _branch_stack.pop_back();
 }
 
 void over(void)
diff --git a/src/stack.hpp b/src/stack.hpp
index 2e92aed..f0abb87 100644
--- a/src/stack.hpp
+++ b/src/stack.hpp
@@ -121,15 +121,15 @@ public:
         return _count;
     }
 
-    // stack access (index is counted from back)
-    object* get_obj(unsigned int index)
+    // stack access (stack_level=0=first out)
+    object* get_obj(unsigned int stack_level)
     {
-        return seq_obj(_count - index - 1);
+        return seq_obj(_count - stack_level - 1);
     }
 
-    object* operator[](unsigned int index)
+    object* operator[](unsigned int stack_level)
     {
-        return seq_obj(_count - index - 1);
+        return seq_obj(_count - stack_level - 1);
     }
 
     object* back()
diff --git a/test/01-all.txt b/test/01-all.txt
index 11f364b..595120a 100644
--- a/test/01-all.txt
+++ b/test/01-all.txt
@@ -6,3 +6,4 @@
 #include test/07-string.txt
 #include test/08-test.txt
 #include test/09-store.txt
+#include test/10-program.txt
diff --git a/test/02-entry.txt b/test/02-entry.txt
index d1738a7..bd64054 100644
--- a/test/02-entry.txt
+++ b/test/02-entry.txt
@@ -6,18 +6,20 @@ erase
 1
 -> stack size should be 1
 -> stack should be 1
-
 drop
+
+# real decimal (2)
 2.345
 -> stack should be 2.345
-
 erase
+
+# real decimal (3)
 1 2.345 3 4.9
 -> stack size should be 4
 -> stack should be 1, 2.345, 3, 4.9
+erase
 
 # real hex
-erase
 0x1234 0x10.10
 -> stack should be 0x1.234p+12, 0x1.01p+4
 
@@ -27,16 +29,16 @@ dec swap dec swap
 erase
 
 # real binary
-erase
 0b11001100
 -> stack should be 204
-
 erase
+
+# real binary (2)
 0b11001100.1101
 -> stack should be 204.8125
+erase
 
 # real inf, nan
-erase
 inf
 @inf@
 +inf
@@ -46,46 +48,76 @@ inf
 nan
 @nan@
 -> stack should be inf, inf, inf, inf, -inf, -inf, nan, nan
+erase
 
 # symbol
-erase
 'test'
 -> stack size should be 1
 -> stack should be 'test'
-
 erase
+
+# symbol (2)
 'test
 -> stack size should be 1
 -> stack should be 'test'
-
 erase
+
+# symbol (3)
 ''
 -> stack size should be 1
 -> stack should be ''
+erase
+
+# symbol (4)
+'
+-> stack size should be 1
+-> stack should be ''
+erase
 
 # string
-erase
 "test string"
 -> stack size should be 1
 -> stack should be "test string"
-
 erase
+
+# string (2)
 "test string
 -> stack size should be 1
 -> stack should be "test string"
+erase
+
+# string (3)
+"
+-> stack size should be 1
+-> stack should be ""
+erase
 
 # program
-erase
 << 'one' >>
 -> stack size should be 1
--> stack should be << 'one'  >>
-
+-> stack should be << 'one' >>
 erase
+
+# program (2)
 << 'one' 2
 -> stack size should be 1
 -> stack should be << 'one' 2 >>
-
 erase
-<< -> n << n 2 + >> >>
+
+# program (3)
+<<
 -> stack size should be 1
--> stack should be << -> n  << n 2 +  >> >>
+-> stack should be <<  >>
+erase
+
+# program (4)
+<< << << <<
+-> stack size should be 1
+-> stack should be << << << <<  >> >> >> >>
+erase
+
+# program (5)
+<< -> n << n 2 * >> >>
+-> stack size should be 1
+-> stack should be << -> n << n 2 * >> >>
+erase
diff --git a/test/03-general.txt b/test/03-general.txt
index 58d0c42..662b6f6 100644
--- a/test/03-general.txt
+++ b/test/03-general.txt
@@ -21,7 +21,7 @@ erase
 
 << -> n << n >> >>
 type
--> stack should be << -> n  << n  >> >>, 'program'
+-> stack should be << -> n << n >> >>, 'program'
 erase
 
 # default
diff --git a/test/05-stack.txt b/test/05-stack.txt
index e1e08ce..511d038 100644
--- a/test/05-stack.txt
+++ b/test/05-stack.txt
@@ -7,14 +7,36 @@
 erase depth
 -> stack should be 0
 
+# swap
+erase
+1 2 swap
+-> stack size should be 2
+-> stack should be 2, 1
+
+# swap with filled stack
+erase
+5 6 1 2 swap
+-> stack size should be 4
+-> stack should be 5, 6, 2, 1
+
+# swap error
+erase
+5 swap
+-> stack size should be 1
+-> error should 2
+
 # drop
 erase
 1 2 3 drop
 -> stack size should be 2
+-> stack should be 1, 2
 
 # drop2
+3
 drop2
--> stack size should be 0
+-> stack size should be 1
+-> stack should be 1
+erase
 
 # drop error
 drop
@@ -46,6 +68,22 @@ drop2 drop2
 -> stack should be 2, 3, 1
 erase
 
+# test rot with start
+5 6 7 1 2 start rot next
+-> stack should be 7, 5, 6
+erase
+
+# test rot with next
+5 6 7 1 2 for i rot next
+-> stack should be 7, 5, 6
+erase
+
+# test rot with filled stack
+5 6 1 2 3 rot
+-> stack size should be 5
+-> stack should be 5, 6, 2, 3, 1
+erase
+
 # test depth
 1 2 3
 depth
@@ -93,6 +131,11 @@ erase
 1 2 3 4 5 4 roll
 -> stack should be 1, 3, 4, 5, 2
 
+# test roll with filled stack
+erase
+10 11 1 2 3 4 5 4 roll
+-> stack should be 10, 11, 1, 3, 4, 5, 2
+
 # test roll error
 erase
 1 2 3 4 5 6 roll
@@ -104,9 +147,14 @@ erase
 10 20 30 40 50 3 rolld
 -> stack should be 10, 20, 50, 30, 40
 
-# test roll error
+# test rolld with filled stack
 erase
-1 2 3 4 5 6 roll
+80 90 10 20 30 40 50 3 rolld
+-> stack should be 80, 90, 10, 20, 50, 30, 40
+
+# test rolld error
+erase
+1 2 3 4 5 6 rolld
 -> stack size should be 6
 -> error should be 2
 
diff --git a/test/07-string.txt b/test/07-string.txt
index c6d6fc7..54e787c 100644
--- a/test/07-string.txt
+++ b/test/07-string.txt
@@ -86,5 +86,5 @@ erase
 # str-> on program
 "<< -> n << n >> >>"
 str->
--> stack should be << -> n  << n  >> >>
+-> stack should be << -> n << n >> >>
 erase