diff --git a/moo/README.md b/moo/README.md
index 3d13f47..74eef5e 100644
--- a/moo/README.md
+++ b/moo/README.md
@@ -62,6 +62,27 @@ class MyClass(Object)
 }
 ```
 
+Class attributes
+
+The word class can be followed by attribute list enclosed in parenthesis. e.g.) class(#limited,#immutable)
+ 
+* #limited - not instantiable with new.
+* #immutable - instantiated object to be read-only.
+* #final - disallow subclasses.
+* #byte, #character, #halfword, #word, #liword, #pointer - 
+  specify the type of a non-pointer object. a non-pointer type can have an additional size 
+  enclosed in parenthesis. e.g.) #character(2)
+  a non-pointer object is not allowed to have named instanced variables.
+  a non-pointer object is always variable indexed.
+* #pointer - specify a pointer variable indexed object. an instantiate object can have extra 
+  object pointers in additon to named instance variables.
+
+```
+class(#word(2)) X(Object) { } 
+X new -> create an object with 2 words.
+X new: 4 -> create an object with 6 words.
+```
+
 ### Flow Control
 ```
 k := if (i < 20) { 30 } else { 40 }.
diff --git a/moo/kernel/System.moo b/moo/kernel/System.moo
index b081acf..e647ca3 100644
--- a/moo/kernel/System.moo
+++ b/moo/kernel/System.moo
@@ -381,7 +381,7 @@ TODO: how to pass all variadic arguments to another variadic methods???
 }
 
 
-class SmallPointer(Object)
+class(#limited) SmallPointer(Object)
 {
 	method(#primitive) asString.
 
@@ -409,6 +409,6 @@ class SmallPointer(Object)
 	method(#primitive) free.
 }
 
-class LargePointer(Object)
+class(#limited,#immutable,#word(1)) LargePointer(Object)
 {
 }
diff --git a/moo/lib/comp.c b/moo/lib/comp.c
index de73c45..5e83199 100644
--- a/moo/lib/comp.c
+++ b/moo/lib/comp.c
@@ -844,6 +844,7 @@ static moo_oop_t string_to_smptr (moo_t* moo, moo_oocs_t* str, moo_ioloc_t* loc)
 {
 	moo_oow_t num = 0;
 	const moo_ooch_t* ptr, * end;
+	moo_oop_t ret;
 
 	ptr = str->ptr,
 	end = str->ptr + str->len;
@@ -873,6 +874,7 @@ static moo_oop_t string_to_smptr (moo_t* moo, moo_oocs_t* str, moo_ioloc_t* loc)
 		ptr++;
 	}
 
+#if 0
 	if (!MOO_IN_SMPTR_RANGE(num))
 	{
 		moo_setsynerr (moo, MOO_SYNERR_SMPTRLITINVAL, loc, str);
@@ -880,6 +882,14 @@ static moo_oop_t string_to_smptr (moo_t* moo, moo_oocs_t* str, moo_ioloc_t* loc)
 	}
 
 	return MOO_SMPTR_TO_OOP(num);
+#else
+	/* TODO: change the function name from string_to_smptr() to string_to_ptr() if this part of code is permanently accepted */
+	if (MOO_IN_SMPTR_RANGE(num)) return MOO_SMPTR_TO_OOP(num);
+	ret = moo_instantiate(moo, moo->_large_pointer, MOO_NULL, 0);
+	if (!ret) return MOO_NULL;
+	MOO_OBJ_SET_WORD_VAL(ret, 0, num);
+	return ret;
+#endif
 }
 
 /* ---------------------------------------------------------------------
diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index d827768..6ea1949 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -4085,8 +4085,9 @@ static moo_pfrc_t pf_error_as_string (moo_t* moo, moo_mod_t* mod, moo_ooi_t narg
 	ec = MOO_OOP_TO_ERROR(rcv);
 	MOO_ASSERT (moo, MOO_IN_SMOOI_RANGE(ec));
 
-/* TODO: error string will be mostly the same.. do i really have to call makestring every time? */
-	s = moo_errnum_to_errstr (ec);
+/* TODO: error string will be mostly the same.. do i really have to call makestring every time? 
+ *       cache the error string object created? */
+	s = moo_errnum_to_errstr(ec);
 	ss = moo_makestring (moo, s, moo_count_oocstr(s));
 	if (!ss) return MOO_PF_FAILURE;
 
diff --git a/moo/lib/fmt.c b/moo/lib/fmt.c
index d82b11c..fc927a4 100644
--- a/moo/lib/fmt.c
+++ b/moo/lib/fmt.c
@@ -1436,7 +1436,7 @@ int moo_fmt_object_ (moo_fmtout_t* fmtout, moo_oop_t oop)
 
 			for (i = 0; i < MOO_OBJ_GET_SIZE(oop); i++)
 			{
-				ch = MOO_OBJ_GET_CHAR_SLOT(oop)[i];
+				ch = MOO_OBJ_GET_CHAR_VAL(oop, i);
 				if ((ch >= '\0' && ch < ' ') || ch == '\\' || ch == '\"') 
 				{
 					escape = 1;
@@ -1451,7 +1451,7 @@ int moo_fmt_object_ (moo_fmtout_t* fmtout, moo_oop_t oop)
 				if (moo_bfmt_out(fmtout, ((c == moo->_symbol)? "#\"": "\"")) <= -1) return -1;
 				for (i = 0; i < MOO_OBJ_GET_SIZE(oop); i++)
 				{
-					ch = MOO_OBJ_GET_CHAR_SLOT(oop)[i];
+					ch = MOO_OBJ_GET_CHAR_VAL(oop, i);
 					if (ch >= '\0' && ch < ' ') 
 					{
 						switch (ch)
diff --git a/moo/lib/gc.c b/moo/lib/gc.c
index 6d75762..fda379f 100644
--- a/moo/lib/gc.c
+++ b/moo/lib/gc.c
@@ -387,13 +387,22 @@ static kernel_class_info_t kernel_classes[] =
 
 	{ 12,
 	  { 'S','m','a','l','l','P','o','i','n','t','e','r' },
-	  0,
+	  MOO_CLASS_SELFSPEC_FLAG_LIMITED,
 	  0,
 	  0,
 	  0,
 	  MOO_OBJ_TYPE_OOP,
 	  MOO_OFFSETOF(moo_t, _small_pointer) },
 
+	{ 12,
+	  { 'L','a','r','g','e','P','o','i','n','t','e','r' },
+	  MOO_CLASS_SELFSPEC_FLAG_LIMITED,
+	  0,
+	  1,  /* #word(1) */
+	  MOO_CLASS_SPEC_FLAG_IMMUTABLE | MOO_CLASS_SPEC_FLAG_INDEXED,
+	  MOO_OBJ_TYPE_WORD,
+	  MOO_OFFSETOF(moo_t, _large_pointer) },
+
 	{ 6,
 	  { 'S','y','s','t','e','m' },
 	  0,
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 00a7538..33690f1 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -1562,6 +1562,7 @@ struct moo_t
 	moo_oop_class_t _fixed_point_decimal; /* FixedPointDecimal */
 
 	moo_oop_class_t _small_pointer;
+	moo_oop_class_t _large_pointer;
 	moo_oop_class_t _system;
 	/* =============================================================
 	 * END KERNEL CLASSES