diff --git a/lib/comp.c b/lib/comp.c
index f4c4a03..8f596a8 100644
--- a/lib/comp.c
+++ b/lib/comp.c
@@ -1949,6 +1949,34 @@ static HCL_INLINE int post_catch (hcl_t* hcl)
 	return 0;
 }
 
+static int compile_throw (hcl_t* hcl, hcl_cnode_t* src)
+{
+	hcl_cnode_t* cmd, * obj;
+	hcl_cframe_t* cf;
+	hcl_ooi_t jump_inst_pos;
+
+	HCL_ASSERT (hcl, HCL_CNODE_IS_CONS(src));
+
+	HCL_ASSERT (hcl, HCL_CNODE_IS_SYMBOL_SYNCODED(HCL_CNODE_CONS_CAR(src), HCL_SYNCODE_THROW));
+
+	cmd = HCL_CNODE_CONS_CDR(src);
+	obj = HCL_CNODE_CONS_CDR(src);
+
+	if (!obj)
+	{
+		/* no value */
+		hcl_setsynerrbfmt (hcl, HCL_SYNERR_ARGCOUNT, HCL_CNODE_GET_LOC(src), HCL_NULL, "no expression specified in %.*js", HCL_CNODE_GET_TOKLEN(cmd), HCL_CNODE_GET_TOKPTR(cmd)); 
+		return -1;
+	}
+	else if (!HCL_CNODE_IS_CONS(obj))
+	{
+		hcl_setsynerrbfmt (hcl, HCL_SYNERR_DOTBANNED, HCL_CNODE_GET_LOC(obj), HCL_CNODE_GET_TOK(obj), "redundant cdr in %.*js", HCL_CNODE_GET_TOKLEN(cmd), HCL_CNODE_GET_TOKPTR(cmd));
+		return -1;
+	}
+
+	return 0;
+}
+
 /* ========================================================================= */
 
 static int compile_while (hcl_t* hcl, hcl_cnode_t* src, int next_cop)
@@ -2165,6 +2193,10 @@ static int compile_cons_xlist_expression (hcl_t* hcl, hcl_cnode_t* obj)
 				if (compile_return(hcl, obj, 1) <= -1) return -1;
 				break;
 
+			case HCL_SYNCODE_THROW:
+				if (compile_throw(hcl, obj) <= -1) return -1;
+				break;
+
 			case HCL_SYNCODE_TRY:
 				if (compile_try(hcl, obj) <= -1) return -1;
 				break;
diff --git a/lib/gc.c b/lib/gc.c
index c6f1b6b..b1e0de6 100644
--- a/lib/gc.c
+++ b/lib/gc.c
@@ -54,7 +54,8 @@ static struct
 	{ 16, { 'r','e','t','u','r','n','-','f','r','o','m','-','h','o','m','e'},
 	                                            HCL_SYNCODE_RETURN_FROM_HOME,  HCL_OFFSETOF(hcl_t,_return_from_home) },
 	{  3, { 's','e','t' },                      HCL_SYNCODE_SET,       HCL_OFFSETOF(hcl_t,_set)    },
-	{  3, { 't','r','y' },                      HCL_SYNCODE_TRY,        HCL_OFFSETOF(hcl_t,_try)     },
+	{  5, { 't','h','r','o','w' },              HCL_SYNCODE_THROW,     HCL_OFFSETOF(hcl_t,_throw)     },
+	{  3, { 't','r','y' },                      HCL_SYNCODE_TRY,       HCL_OFFSETOF(hcl_t,_try)     },
 	{  5, { 'u','n','t','i','l' },              HCL_SYNCODE_UNTIL,     HCL_OFFSETOF(hcl_t,_until)  },
 	{  5, { 'w','h','i','l','e' },              HCL_SYNCODE_WHILE,     HCL_OFFSETOF(hcl_t,_while)  }
 };
diff --git a/lib/hcl.h b/lib/hcl.h
index c105ce8..bb4abc7 100644
--- a/lib/hcl.h
+++ b/lib/hcl.h
@@ -1416,6 +1416,7 @@ struct hcl_t
 	hcl_oop_t _return; /* symbol */
 	hcl_oop_t _return_from_home; /* symbol */
 	hcl_oop_t _set;    /* symbol */
+	hcl_oop_t _throw;  /* symbol */
 	hcl_oop_t _try;    /* symbol */
 	hcl_oop_t _until;  /* symbol */
 	hcl_oop_t _while;  /* symbol */
@@ -1689,6 +1690,7 @@ enum hcl_syncode_t
 	HCL_SYNCODE_RETURN,
 	HCL_SYNCODE_RETURN_FROM_HOME,
 	HCL_SYNCODE_SET,
+	HCL_SYNCODE_THROW,
 	HCL_SYNCODE_TRY,
 	HCL_SYNCODE_UNTIL,
 	HCL_SYNCODE_WHILE
diff --git a/lib/heap.c b/lib/heap.c
index 52dd8f0..b577d64 100644
--- a/lib/heap.c
+++ b/lib/heap.c
@@ -38,7 +38,7 @@ static void* xma_realloc (hcl_mmgr_t* mmgr, void* ptr, hcl_oow_t size)
 
 static void xma_free (hcl_mmgr_t* mmgr, void* ptr)
 {
-	return hcl_xma_free (mmgr->ctx, ptr);
+	hcl_xma_free (mmgr->ctx, ptr);
 }
 
 hcl_heap_t* hcl_makeheap (hcl_t* hcl, hcl_oow_t size)
diff --git a/lib/xutl-sa.h b/lib/xutl-sa.h
index 1788112..c30137c 100644
--- a/lib/xutl-sa.h
+++ b/lib/xutl-sa.h
@@ -184,7 +184,7 @@ int str_to_sockaddr (hcl_t* hcl, const ooch_t* str, hcl_oow_t len, hcl_sckaddr_t
 		if (*p == '%')
 		{
 			/* handle scope id */
-			hcl_uint32_t x;
+			hcl_uint32_t x, y;
 
 			p++; /* skip % */
 
@@ -198,19 +198,20 @@ int str_to_sockaddr (hcl_t* hcl, const ooch_t* str, hcl_oow_t len, hcl_sckaddr_t
 			if (*p >= '0' && *p <= '9') 
 			{
 				/* numeric scope id */
-				nwad->in6.sin6_scope_id = 0;
+				y = 0;
 				do
 				{
-					x = nwad->in6.sin6_scope_id * 10 + (*p - '0');
-					if (x < nwad->in6.sin6_scope_id) 
+					x = y * 10 + (*p - '0');
+					if (x < y)
 					{
 						if (hcl) hcl_seterrbfmt (hcl, HCL_EINVAL, "scope id too large");
 						return -1; /* overflow */
 					}
-					nwad->in6.sin6_scope_id = x;
+					y = x;
 					p++;
 				}
 				while (p < end && *p >= '0' && *p <= '9');
+				//nwad->in6.sin6_scope_id = y;
 			}
 			else
 			{
@@ -220,7 +221,7 @@ TODO:
 				const ooch_t* stmp = p;
 				unsigned int index;
 				do p++; while (p < end && *p != ']');
-				if (hcl_nwifwcsntoindex (stmp, p - stmp, &index) <= -1) return -1;
+				if (hcl_nwifwcsntoindex(stmp, p - stmp, &index) <= -1) return -1;
 				tmpad.u.in6.scope = index;
 #endif
 			}
@@ -259,7 +260,7 @@ TODO:
 			if (p < end && *p == '%')
 			{
 				/* handle scope id */
-				hcl_uint32_t x;
+				hcl_uint32_t x, y;
 
 				p++; /* skip % */
 
@@ -273,19 +274,20 @@ TODO:
 				if (*p >= '0' && *p <= '9') 
 				{
 					/* numeric scope id */
-					nwad->in6.sin6_scope_id = 0;
+					y = 0;
 					do
 					{
-						x = nwad->in6.sin6_scope_id * 10 + (*p - '0');
-						if (x < nwad->in6.sin6_scope_id) 
+						x = y * 10 + (*p - '0');
+						if (x < y)
 						{
 							if (hcl) hcl_seterrbfmt (hcl, HCL_EINVAL, "scope id too large");
 							return -1; /* overflow */
 						}
-						nwad->in6.sin6_scope_id = x;
+						y = x;
 						p++;
 					}
 					while (p < end && *p >= '0' && *p <= '9');
+					//nwad->in6.sin6_scope_id = y;
 				}
 				else
 				{