diff --git a/hawk/lib/Hawk.hpp b/hawk/lib/Hawk.hpp
index 280761c8..a9ee84cd 100644
--- a/hawk/lib/Hawk.hpp
+++ b/hawk/lib/Hawk.hpp
@@ -1045,6 +1045,8 @@ public:
 			return p;
 		}
 
+		int getType () const { return hawk_get_val_type(this->val); }
+
 		int getInt (hawk_int_t* v) const;
 		int getFlt (hawk_flt_t* v) const;
 		int getNum (hawk_int_t* lv, hawk_flt_t* fv) const;
diff --git a/hawk/lib/HawkStd.cpp b/hawk/lib/HawkStd.cpp
index ecab3c94..745845f0 100644
--- a/hawk/lib/HawkStd.cpp
+++ b/hawk/lib/HawkStd.cpp
@@ -1279,7 +1279,7 @@ int HawkStd::SourceFile::open (Data& io)
 
 		if (this->cmgr) hawk_sio_setcmgr (sio, this->cmgr);
 		io.setName (xpath);
-		io.setPath (xpath); // let parser use this path, especially upon an error
+		io.setPath (xpath); // let the parser use this path, especially upon an error
 	}
 	else
 	{
@@ -1367,11 +1367,8 @@ hawk_ooi_t HawkStd::SourceFile::write (Data& io, const hawk_ooch_t* buf, hawk_oo
 
 HawkStd::SourceString::~SourceString ()
 {
-	if (this->_hawk) 
-	{
-		HAWK_ASSERT (this->str != HAWK_NULL);
-		hawk_freemem (this->_hawk, this->str);
-	}
+	HAWK_ASSERT (this->_hawk == HAWK_NULL);
+	HAWK_ASSERT (this->str == HAWK_NULL);
 }
 
 int HawkStd::SourceString::open (Data& io)
@@ -1394,21 +1391,21 @@ int HawkStd::SourceString::open (Data& io)
 			if (this->_type == STR_UCH)
 			{
 			#if defined(HAWK_OOCH_IS_UCH)
-				this->str = hawk_dupucstr(this->_hawk, (hawk_uch_t*)this->_str, HAWK_NULL);
+				this->str = hawk_dupucstr(this->_hawk, (const hawk_uch_t*)this->_str, HAWK_NULL);
 			#else
-				this->str = hawk_duputobcstr(this->_hawk, (hawk_uch_t*)this->_str, HAWK_NULL);
+				this->str = hawk_duputobcstr(this->_hawk, (const hawk_uch_t*)this->_str, HAWK_NULL);
 			#endif
 			}
 			else
 			{
 				HAWK_ASSERT (this->_type == STR_BCH);
 			#if defined(HAWK_OOCH_IS_UCH)
-				this->str = hawk_dupbtoucstr(this->_hawk, (hawk_bch_t*)this->_str, HAWK_NULL, 0);
+				this->str = hawk_dupbtoucstr(this->_hawk, (const hawk_bch_t*)this->_str, HAWK_NULL, 0);
 			#else
-				this->str = hawk_dupbcstr(this->_hawk, (hawk_bch_t*)this->_str, HAWK_NULL);
+				this->str = hawk_dupbcstr(this->_hawk, (const hawk_bch_t*)this->_str, HAWK_NULL);
 			#endif
 			}
-			if (!this->str) 
+			if (HAWK_UNLIKELY(!this->str)) 
 			{
 				this->_hawk = HAWK_NULL;
 				return -1;
@@ -1448,7 +1445,7 @@ int HawkStd::SourceString::open (Data& io)
 					if (totlen >= HAWK_COUNTOF(fbuf))
 					{
 						dbuf = (hawk_ooch_t*)hawk_allocmem((hawk_t*)io, HAWK_SIZEOF(hawk_ooch_t) * (totlen + 1));
-						if (!dbuf) return -1;
+						if (HAWK_UNLIKELY(!dbuf)) return -1;
 						path = dbuf;
 					}
 					else path = fbuf;
@@ -1464,7 +1461,7 @@ int HawkStd::SourceString::open (Data& io)
 		{
 			xpath = hawk_addsionamewithoochars((hawk_t*)io, ioname, hawk_count_oocstr(ioname));
 		}
-		if (!xpath) return -1;
+		if (HAWK_UNLIKELY(!xpath)) return -1;
 
 		sio = open_sio(
 			io, HAWK_NULL, xpath,
diff --git a/hawk/lib/hawk.h b/hawk/lib/hawk.h
index 40ae059a..03a9fc37 100644
--- a/hawk/lib/hawk.h
+++ b/hawk/lib/hawk.h
@@ -130,6 +130,7 @@ struct hawk_rtx_alt_t
 
 /* ------------------------------------------------------------------------ */
 
+/* garbage collection header */
 typedef struct hawk_gch_t hawk_gch_t;
 struct hawk_gch_t
 {
@@ -3609,6 +3610,10 @@ HAWK_EXPORT hawk_val_t* hawk_get_nil_val (
 	void
 );
 
+HAWK_EXPORT int hawk_get_val_type (
+	hawk_val_t* val
+);
+
 #if defined(__cplusplus)
 }
 #endif
diff --git a/hawk/lib/val-prv.h b/hawk/lib/val-prv.h
index fd3371c5..d6b8eca2 100644
--- a/hawk/lib/val-prv.h
+++ b/hawk/lib/val-prv.h
@@ -142,11 +142,12 @@ struct hawk_val_rchunk_t
 #define HAWK_VTR_TO_QCHAR(p) ((hawk_ooch_t)((hawk_uintptr_t)(p) >> HAWK_VTR_NUM_TYPE_BITS_LO))
 #define HAWK_VTR_TO_QBCHR(p) ((hawk_ooch_t)((hawk_uintptr_t)(p) >> HAWK_VTR_NUM_TYPE_BITS_LOHI))
 
-#define HAWK_RTX_GETVALTYPE(rtx,p) (HAWK_VTR_IS_QINT(p)? HAWK_VAL_INT: \
-                                    HAWK_VTR_IS_QCHAR(p)? HAWK_VAL_CHAR: \
-                                    HAWK_VTR_IS_QBCHR(p)? HAWK_VAL_BCHR: (p)->v_type)
+#define HAWK_GET_VAL_TYPE(p) (HAWK_VTR_IS_QINT(p)? HAWK_VAL_INT: \
+                              HAWK_VTR_IS_QCHAR(p)? HAWK_VAL_CHAR: \
+                              HAWK_VTR_IS_QBCHR(p)? HAWK_VAL_BCHR: (p)->v_type)
 
-#define HAWK_RTX_GETINTFROMVAL(rtx,p) ((HAWK_VTR_IS_QINT(p)? (hawk_int_t)HAWK_VTR_TO_QINT(p): ((hawk_val_int_t*)(p))->i_val))
+#define HAWK_RTX_GETVALTYPE(rtx, p) HAWK_GET_VAL_TYPE(p)
+#define HAWK_RTX_GETINTFROMVAL(rtx, p) ((HAWK_VTR_IS_QINT(p)? (hawk_int_t)HAWK_VTR_TO_QINT(p): ((hawk_val_int_t*)(p))->i_val))
 #define HAWK_RTX_GETCHARFROMVAL(rtx, p) (HAWK_VTR_TO_QCHAR(p))
 #define HAWK_RTX_GETBCHRFROMVAL(rtx, p) (HAWK_VTR_TO_QBCHR(p))
 
diff --git a/hawk/lib/val.c b/hawk/lib/val.c
index d74222fa..fdb56671 100644
--- a/hawk/lib/val.c
+++ b/hawk/lib/val.c
@@ -469,6 +469,11 @@ static HAWK_INLINE hawk_val_t* gc_calloc_val (hawk_rtx_t* rtx, hawk_oow_t size)
 
 /* --------------------------------------------------------------------- */
 
+int hawk_get_val_type (hawk_val_t* val)
+{
+	return HAWK_GET_VAL_TYPE(val);
+}
+
 hawk_val_t* hawk_get_nil_val (void)
 {
 	return (hawk_val_t*)&hawk_nil;