diff --git a/stix/lib/comp.c b/stix/lib/comp.c
index 4a5ad05..3feaa3d 100644
--- a/stix/lib/comp.c
+++ b/stix/lib/comp.c
@@ -2169,9 +2169,10 @@ wprintf (L"METHOD NAME ==> [%S] temporaries => %d\n", fsc->met.name.buf, fsc->me
 
 enum class_mod_t
 {
-	BYTE_INDEXED    = (1 << 0),
-	WORD_INDEXED    = (1 << 1),
-	POINTER_INDEXED = (1 << 2)
+	CLASS_BYTE_INDEXED    = (1 << 0),
+	CLASS_WORD_INDEXED    = (1 << 1),
+	CLASS_POINTER_INDEXED = (1 << 2),
+	CLASS_EXTEND          = (1 << 3)
 };
 
 enum dcl_mod_t
@@ -2209,6 +2210,10 @@ static int compile_class_declare (stix_t* stix)
 				/* #dcl(#instance) */
 				dcl_mod &= ~(DCL_CLASS | DCL_CLASSINST);
 			}
+			else
+			{
+				break;
+			}
 		}
 		while (1);
 
@@ -2217,6 +2222,8 @@ static int compile_class_declare (stix_t* stix)
 			set_syntax_error (stix, STIX_SYNERR_RPAREN, &stix->c->tok.loc, &stix->c->tok.name);
 			return -1;
 		}
+
+		GET_TOKEN (stix);
 	}
 
 	do
@@ -2272,20 +2279,20 @@ static int compile_class_definition (stix_t* stix)
 			if (is_token_ksym(stix, KSYM_BYTE))
 			{
 				/* #class(#byte) */
-				class_mod &= ~(BYTE_INDEXED | WORD_INDEXED | POINTER_INDEXED);
-				class_mod |= BYTE_INDEXED;
+				class_mod &= ~(CLASS_BYTE_INDEXED | CLASS_WORD_INDEXED | CLASS_POINTER_INDEXED);
+				class_mod |= CLASS_BYTE_INDEXED;
 			}
 			else if (is_token_ksym(stix, KSYM_WORD))
 			{
 				/* #class(#word) */
-				class_mod &= ~(BYTE_INDEXED | WORD_INDEXED | POINTER_INDEXED);
-				class_mod |= WORD_INDEXED;
+				class_mod &= ~(CLASS_BYTE_INDEXED | CLASS_WORD_INDEXED | CLASS_POINTER_INDEXED);
+				class_mod |= CLASS_WORD_INDEXED;
 			}
 			else if (is_token_ksym(stix, KSYM_POINTER))
 			{
 				/* #class(#pointer) */
-				class_mod &= ~(BYTE_INDEXED | WORD_INDEXED | POINTER_INDEXED);
-				class_mod |= POINTER_INDEXED;
+				class_mod &= ~(CLASS_BYTE_INDEXED | CLASS_WORD_INDEXED | CLASS_POINTER_INDEXED);
+				class_mod |= CLASS_POINTER_INDEXED;
 			}
 			/* place other modifiers here */
 			else 
@@ -2315,19 +2322,45 @@ static int compile_class_definition (stix_t* stix)
 
 	if (stix->c->tok.type == STIX_IOTOK_LPAREN)
 	{
-		/* superclass is specified */
+		/* superclass is specified. new class defintion.
+		 * #class Class(Object) 
+		 */
+		GET_TOKEN (stix);
+
+		/* TODO: multiple inheritance */
+
+		if (stix->c->tok.type != STIX_IOTOK_IDENT)
+		{
+			/* superclass name expected */
+			set_syntax_error (stix, STIX_SYNERR_IDENT, &stix->c->tok.loc, &stix->c->tok.name);
+			return -1;
+		}
+
+		GET_TOKEN (stix);
+		if (stix->c->tok.type != STIX_IOTOK_RPAREN)
+		{
+			set_syntax_error (stix, STIX_SYNERR_RPAREN, &stix->c->tok.loc, &stix->c->tok.name);
+			return -1;
+		}
+
+		GET_TOKEN (stix);
 	}
-	
+	else
+	{
+		/* extending class */
+		class_mod |= CLASS_EXTEND;
+	}
+
 	if (stix->c->tok.type != STIX_IOTOK_LBRACE)
 	{
 		set_syntax_error (stix, STIX_SYNERR_LBRACE, &stix->c->tok.loc, &stix->c->tok.name);
 		return -1;
 	}
 
+	GET_TOKEN (stix);
+
 	while (1)
 	{
-		GET_TOKEN (stix);
-
 		if (is_token_ksym(stix, KSYM_DCL) || is_token_ksym(stix, KSYM_DECLARE))
 		{
 			/* variable definition. #dcl or #declare */
diff --git a/stix/lib/main.c b/stix/lib/main.c
index 85b0609..439eae0 100644
--- a/stix/lib/main.c
+++ b/stix/lib/main.c
@@ -190,7 +190,13 @@ static char* syntax_error_msg[] =
 	"no character after $",
 	"no valid character after #",
 	"missing colon",
-	"string expected" /* string expected in place of ${1} */
+	"string expected", /* string expected in place of ${1} */
+	"{ expected",
+	"} expected",
+	") expected",
+	". expected",
+	"wrong class modifier",
+	"identifier expected"
 };
 
 int main (int argc, char* argv[])
@@ -267,15 +273,30 @@ printf ("%p\n", a);
 		if (stix->errnum == STIX_ESYNTAX)
 		{
 			stix_synerr_t synerr;
+			stix_bch_t bcs[1024]; /* TODO: right buffer size */
+			stix_size_t bcslen, ucslen;
+
 			stix_getsynerr (stix, &synerr);
-			printf ("ERROR: syntax error at line %lu column %lu - %s", 
+
+			printf ("ERROR: ");
+			if (synerr.loc.file)
+			{
+				bcslen = STIX_COUNTOF(bcs);
+				ucslen = ~(stix_size_t)0;
+				if (stix_ucstoutf8 (synerr.loc.file, &ucslen, bcs, &bcslen) >= 0)
+				{
+					printf ("%.*s ", (int)bcslen, bcs);
+				}
+			}
+
+
+			printf ("syntax error at line %lu column %lu - %s", 
 				(unsigned long int)synerr.loc.line, (unsigned long int)synerr.loc.colm,
 				syntax_error_msg[synerr.num]);
 			if (synerr.tgt.len > 0)
 			{
-				stix_bch_t bcs[1024]; /* TODO: right buffer size */
-				stix_size_t bcslen = STIX_COUNTOF(bcs);
-				stix_size_t ucslen = synerr.tgt.len;
+				bcslen = STIX_COUNTOF(bcs);
+				ucslen = synerr.tgt.len;
 
 				if (stix_ucstoutf8 (synerr.tgt.ptr, &ucslen, bcs, &bcslen) >= 0)
 				{
diff --git a/stix/lib/memo.txt b/stix/lib/memo.txt
index a55a2dd..6efd391 100644
--- a/stix/lib/memo.txt
+++ b/stix/lib/memo.txt
@@ -116,7 +116,7 @@ stix stix.im
 #class(#byte) Association(Magnitude) 
 {
 	declare a, b, c.
-	declare(#class_instance) x.
+	declare(#classinst) x.
 	declare(#class) MAX_SIZE.
 
 	function(#class) initialize
@@ -500,7 +500,7 @@ class Association -> revisit the Association class defined previsously. Revisiti
 
 ## class instance variable can be accessed inside the class method only.
 
-	declare(#class_instance) d, e, f
+	declare(#classinst) d, e, f
 
 ## All instance variables are protected by default.
 	declare key, value.
@@ -508,7 +508,7 @@ class Association -> revisit the Association class defined previsously. Revisiti
 
 ##
 ##	declare(#class) a, b, c.   ## class variables
-##	declare(#class_instance) a, b, c. ## class instance variables
+##	declare(#classinst) a, b, c. ## class instance variables
 ##	declare(#instance) a, b, c. ## isntance variables
 ##	declare a,b, c. ## instance variables
 
@@ -525,9 +525,9 @@ class Association -> revisit the Association class defined previsously. Revisiti
 ## Casing is not used to differentiate variable kinds like global local temporary etc.
 
 ## other modifiers (EXPERIMENTAL. JUST THINKING).
-## declare(#class,#public,#rw) x. x can be accessed by other classes in read-write mode.
+## declare(#class #public #rw) x. x can be accessed by other classes in read-write mode.
 ## function(#private) xxx xxx is a private method
-## function(#class,#private) xxx xxx is private class method.
+## function(#class #private) xxx xxx is private class method.
 
 	function(#class) initialize
 	{