diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 5631a61..229d99d 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -413,6 +413,12 @@ struct moo_obj_word_t
 	moo_oow_t slot[1];
 };
 
+#define MOO_OBJ_GET_OOP_SLOT(oop)      (((moo_oop_oop_t)(oop))->slot)
+#define MOO_OBJ_GET_CHAR_SLOT(oop)     (((moo_oop_char_t)(oop))->slot)
+#define MOO_OBJ_GET_BYTE_SLOT(oop)     (((moo_oop_byte_t)(oop))->slot)
+#define MOO_OBJ_GET_HALFWORD_SLOT(oop) (((moo_oop_halfword_t)(oop))->slot)
+#define MOO_OBJ_GET_WORD_SLOT(oop)     (((moo_oop_word_t)(oop))->slot)
+
 typedef struct moo_trailer_t moo_trailer_t;
 struct moo_trailer_t
 {
@@ -420,6 +426,7 @@ struct moo_trailer_t
 	moo_oob_t slot[1];
 };
 
+
 #define MOO_SET_NAMED_INSTVARS 2
 typedef struct moo_set_t moo_set_t;
 typedef struct moo_set_t* moo_oop_set_t;
diff --git a/moo/mod/ffi.c b/moo/mod/ffi.c
index 2cbd874..36fac29 100644
--- a/moo/mod/ffi.c
+++ b/moo/mod/ffi.c
@@ -243,11 +243,12 @@ static moo_pfrc_t pf_call (moo_t* moo, moo_ooi_t nargs)
 /* TOOD: check if arg is a string. */
 /* TODO: free all duplicated strings after call */
 			#if defined(MOO_OOCH_IS_UCH)
-				ptr = moo_dupootobchars (moo, ((moo_oop_char_t)arg)->slot, MOO_OBJ_GET_SIZE(arg), MOO_NULL);
-				if (!ptr) goto softfail; /* out of system memory or conversion error - soft failure */
+				ptr = moo_dupootobchars (moo, MOO_OBJ_GET_CHAR_SLOT(arg), MOO_OBJ_GET_SIZE(arg), MOO_NULL);
 			#else
-				ptr = moo_dupoochars (moo, ((moo_oop_char_t)arg)->slot, MOO_OBJ_GET_SIZE(arg));
+				ptr = MOO_OBJ_GET_CHAR_SLOT(arg);
+				/*ptr = moo_dupoochars (moo, MOO_OBJ_GET_CHAR_SLOT(arg), MOO_OBJ_GET_SIZE(arg));*/
 			#endif
+				if (!ptr) goto softfail; /* out of system memory or conversion error - soft failure */
 
 				dcArgPointer (dc, ptr);
 				j++;
@@ -259,11 +260,12 @@ static moo_pfrc_t pf_call (moo_t* moo, moo_ooi_t nargs)
 				moo_uch_t* ptr;
 
 			#if defined(MOO_OOCH_IS_UCH)
-				ptr = moo_dupoochars (moo, ((moo_oop_char_t)arg)->slot, MOO_OBJ_GET_SIZE(arg));
+				ptr = MOO_OBJ_GET_CHAR_SLOT(arg);
+				/*ptr = moo_dupoochars (moo, MOO_OBJ_GET_CHAR_SLOT(arg), MOO_OBJ_GET_SIZE(arg));*/
 			#else
-				ptr = moo_dupootouchars (moo, ((moo_oop_char_t)arg)->slot, MOO_OBJ_GET_SIZE(arg), MOO_NULL);
-				if (!ptr) goto softfail; /* out of system memory or conversion error - soft failure */
+				ptr = moo_dupootouchars (moo, MOO_OBJ_GET_CHAR_SLOT(arg), MOO_OBJ_GET_SIZE(arg), MOO_NULL);
 			#endif
+				if (!ptr) goto softfail; /* out of system memory or conversion error - soft failure */
 
 				dcArgPointer (dc, ptr);
 				j++;
diff --git a/moo/mod/stdio.c b/moo/mod/stdio.c
index 005912e..3f9a92e 100644
--- a/moo/mod/stdio.c
+++ b/moo/mod/stdio.c
@@ -69,12 +69,12 @@ static moo_pfrc_t pf_open (moo_t* moo, moo_ooi_t nargs)
 #if defined(MOO_OOCH_IS_UCH)
 	ucslen = MOO_OBJ_GET_SIZE(name);
 	bcslen = MOO_COUNTOF(namebuf) - 1;
-	if (moo_convootobchars (moo, name->slot, &ucslen, namebuf, &bcslen) <= -1) goto reterr;
+	if (moo_convootobchars (moo, name->slot, &ucslen, namebuf, &bcslen) <= -1) goto softfail;
 	namebuf[bcslen] = '\0';
 
 	ucslen = MOO_OBJ_GET_SIZE(mode);
 	bcslen = MOO_COUNTOF(modebuf) - 1;
-	if (moo_convootobchars (moo, mode->slot, &ucslen, modebuf, &bcslen) <= -1) goto reterr;
+	if (moo_convootobchars (moo, mode->slot, &ucslen, modebuf, &bcslen) <= -1) goto softfail;
 	modebuf[bcslen] = '\0';
 
 	rcv->fp = fopen (namebuf, modebuf);
@@ -84,13 +84,13 @@ static moo_pfrc_t pf_open (moo_t* moo, moo_ooi_t nargs)
 	if (!rcv->fp) 
 	{
 		moo_seterrnum (moo, moo_syserrtoerrnum(errno));
-		goto reterr;
+		goto softfail;
 	}
 
 	MOO_STACK_SETRETTORCV (moo, nargs);
 	return MOO_PF_SUCCESS;
 
-reterr:
+softfail:
 	MOO_STACK_SETRETTOERROR (moo, nargs);
 	return MOO_PF_SUCCESS;
 }
@@ -159,13 +159,13 @@ static moo_pfrc_t __pf_puts (moo_t* moo, moo_ooi_t nargs, moo_oow_t limit)
 /* TODO: implement character conversion into stdio and use it instead of vm's conversion facility. */
 				if ((n = moo_convootobchars (moo, &x->slot[ucspos], &ucslen, bcs, &bcslen)) <= -1)
 				{
-					if (n != -2 || ucslen <= 0) goto reterr;
+					if (n != -2 || ucslen <= 0) goto softfail;
 				}
 
 				if (fwrite (bcs, 1, bcslen, rcv->fp) < bcslen)
 				{
 					moo_seterrnum (moo, moo_syserrtoerrnum(errno));
-					goto reterr;
+					goto softfail;
 				}
 
 		/* TODO: abort looping for async processing???? */
@@ -176,14 +176,14 @@ static moo_pfrc_t __pf_puts (moo_t* moo, moo_ooi_t nargs, moo_oow_t limit)
 		else
 		{
 			moo_seterrnum (moo, MOO_EINVAL);
-			goto reterr;
+			goto softfail;
 		}
 	}
 
 	MOO_STACK_SETRETTORCV (moo, nargs);
 	return MOO_PF_SUCCESS;
 
-reterr:
+softfail:
 	MOO_STACK_SETRETTOERROR (moo, nargs);
 	return MOO_PF_SUCCESS;
 }