diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index c608349..b2143d1 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -1841,7 +1841,7 @@ static moo_pfrc_t pf_dump (moo_t* moo, moo_ooi_t nargs)
 	return MOO_PF_SUCCESS;
 }
 
-static void log_char_object (moo_t* moo, moo_log_masks_t mask, moo_oop_char_t msg)
+static void log_char_object (moo_t* moo, moo_bitmask_t mask, moo_oop_char_t msg)
 {
 	moo_ooi_t n;
 	moo_oow_t rem;
@@ -3354,7 +3354,7 @@ static moo_pfrc_t pf_strlen (moo_t* moo, moo_ooi_t nargs)
 static moo_pfrc_t pf_system_log (moo_t* moo, moo_ooi_t nargs)
 {
 	moo_oop_t msg, level;
-	moo_log_masks_t mask;
+	moo_bitmask_t mask;
 	moo_ooi_t k;
 
 	MOO_ASSERT (moo, nargs >=  2);
diff --git a/moo/lib/logfmt.c b/moo/lib/logfmt.c
index c441468..a207973 100644
--- a/moo/lib/logfmt.c
+++ b/moo/lib/logfmt.c
@@ -130,14 +130,14 @@ static moo_bch_t bch_nullstr[] = { '(','n','u','l','l', ')','\0' };
 
 typedef int (*moo_fmtout_putch_t) (
 	moo_t*          moo,
-	moo_log_masks_t mask,
+	moo_bitmask_t mask,
 	moo_ooch_t      c,
 	moo_oow_t       len
 );
 
 typedef int (*moo_fmtout_putcs_t) (
 	moo_t*            moo,
-	moo_log_masks_t   mask,
+	moo_bitmask_t   mask,
 	const moo_ooch_t* ptr,
 	moo_oow_t         len
 );
@@ -146,7 +146,7 @@ typedef struct moo_fmtout_t moo_fmtout_t;
 struct moo_fmtout_t
 {
 	moo_oow_t            count; /* out */
-	moo_log_masks_t      mask;  /* in */
+	moo_bitmask_t      mask;  /* in */
 	moo_fmtout_putch_t   putch; /* in */
 	moo_fmtout_putcs_t   putcs; /* in */
 };
@@ -184,7 +184,7 @@ static moo_bch_t* sprintn_upper (moo_bch_t* nbuf, moo_uintmax_t num, int base, m
 }
 
 /* ------------------------------------------------------------------------- */
-static int put_ooch (moo_t* moo, moo_log_masks_t mask, moo_ooch_t ch, moo_oow_t len)
+static int put_ooch (moo_t* moo, moo_bitmask_t mask, moo_ooch_t ch, moo_oow_t len)
 {
 	/* this is not equivalent to put_oocs(moo,mask,&ch, 1);
 	 * this function is to emit a single character multiple times */
@@ -281,7 +281,7 @@ redo:
 	return 1; /* success */
 }
 
-static int put_oocs (moo_t* moo, moo_log_masks_t mask, const moo_ooch_t* ptr, moo_oow_t len)
+static int put_oocs (moo_t* moo, moo_bitmask_t mask, const moo_ooch_t* ptr, moo_oow_t len)
 {
 	moo_oow_t rem;
 
@@ -374,9 +374,9 @@ redo:
 
 /* ------------------------------------------------------------------------- */
 
-typedef moo_ooi_t (*outbfmt_t) (moo_t* moo, moo_log_masks_t mask, const moo_bch_t* fmt, ...);
+typedef moo_ooi_t (*outbfmt_t) (moo_t* moo, moo_bitmask_t mask, const moo_bch_t* fmt, ...);
 
-static int print_object (moo_t* moo, moo_log_masks_t mask, moo_oop_t oop, outbfmt_t outbfmt)
+static int print_object (moo_t* moo, moo_bitmask_t mask, moo_oop_t oop, outbfmt_t outbfmt)
 {
 	if (oop == moo->_nil)
 	{
@@ -612,7 +612,7 @@ static int _logufmtv (moo_t* moo, const moo_uch_t* fmt, moo_fmtout_t* data, va_l
 	return __logufmtv (moo, fmt, data, ap, moo_logbfmt);
 }
 
-moo_ooi_t moo_logbfmt (moo_t* moo, moo_log_masks_t mask, const moo_bch_t* fmt, ...)
+moo_ooi_t moo_logbfmt (moo_t* moo, moo_bitmask_t mask, const moo_bch_t* fmt, ...)
 {
 	int x;
 	va_list ap;
@@ -645,7 +645,7 @@ moo_ooi_t moo_logbfmt (moo_t* moo, moo_log_masks_t mask, const moo_bch_t* fmt, .
 	return (x <= -1)? -1: fo.count;
 }
 
-moo_ooi_t moo_logufmt (moo_t* moo, moo_log_masks_t mask, const moo_uch_t* fmt, ...)
+moo_ooi_t moo_logufmt (moo_t* moo, moo_bitmask_t mask, const moo_uch_t* fmt, ...)
 {
 	int x;
 	va_list ap;
@@ -679,7 +679,7 @@ moo_ooi_t moo_logufmt (moo_t* moo, moo_log_masks_t mask, const moo_uch_t* fmt, .
  * ERROR MESSAGE FORMATTING
  * -------------------------------------------------------------------------- */
 
-static int put_errch (moo_t* moo, moo_log_masks_t mask, moo_ooch_t ch, moo_oow_t len)
+static int put_errch (moo_t* moo, moo_bitmask_t mask, moo_ooch_t ch, moo_oow_t len)
 {
 	moo_oow_t max;
 
@@ -698,7 +698,7 @@ static int put_errch (moo_t* moo, moo_log_masks_t mask, moo_ooch_t ch, moo_oow_t
 	return 1; /* success */
 }
 
-static int put_errcs (moo_t* moo, moo_log_masks_t mask, const moo_ooch_t* ptr, moo_oow_t len)
+static int put_errcs (moo_t* moo, moo_bitmask_t mask, const moo_ooch_t* ptr, moo_oow_t len)
 {
 	moo_oow_t max;
 
@@ -715,7 +715,7 @@ static int put_errcs (moo_t* moo, moo_log_masks_t mask, const moo_ooch_t* ptr, m
 }
 
 
-static moo_ooi_t __errbfmtv (moo_t* moo, moo_log_masks_t mask, const moo_bch_t* fmt, ...);
+static moo_ooi_t __errbfmtv (moo_t* moo, moo_bitmask_t mask, const moo_bch_t* fmt, ...);
 
 static int _errbfmtv (moo_t* moo, const moo_bch_t* fmt, moo_fmtout_t* data, va_list ap)
 {
@@ -727,7 +727,7 @@ static int _errufmtv (moo_t* moo, const moo_uch_t* fmt, moo_fmtout_t* data, va_l
 	return __logufmtv (moo, fmt, data, ap, __errbfmtv);
 }
 
-static moo_ooi_t __errbfmtv (moo_t* moo, moo_log_masks_t mask, const moo_bch_t* fmt, ...)
+static moo_ooi_t __errbfmtv (moo_t* moo, moo_bitmask_t mask, const moo_bch_t* fmt, ...)
 {
 	va_list ap;
 	moo_fmtout_t fo;
diff --git a/moo/lib/main.c b/moo/lib/main.c
index 7c91e60..daa7422 100644
--- a/moo/lib/main.c
+++ b/moo/lib/main.c
@@ -214,7 +214,7 @@ struct xtn_t
 	int vm_running;
 
 	int logfd;
-	moo_log_masks_t logmask;
+	moo_bitmask_t logmask;
 	int logfd_istty;
 	
 	struct
@@ -657,7 +657,7 @@ static void flush_log (moo_t* moo, int fd)
 	}
 }
 
-static void log_write (moo_t* moo, moo_log_masks_t mask, const moo_ooch_t* msg, moo_oow_t len)
+static void log_write (moo_t* moo, moo_bitmask_t mask, const moo_ooch_t* msg, moo_oow_t len)
 {
 	moo_bch_t buf[256];
 	moo_oow_t ucslen, bcslen, msgidx;
@@ -2213,7 +2213,7 @@ static int handle_logopt (moo_t* moo, const moo_bch_t* str)
 	xtn_t* xtn = moo_getxtn (moo);
 	moo_bch_t* xstr = (moo_bch_t*)str;
 	moo_bch_t* cm, * flt;
-	moo_log_masks_t logmask;
+	moo_bitmask_t logmask;
 
 	cm = moo_find_bchar_in_bcstr (xstr, ',');
 	if (cm) 
@@ -2299,7 +2299,7 @@ static int handle_dbgopt (moo_t* moo, const moo_bch_t* str)
 	xtn_t* xtn = moo_getxtn (moo);
 	const moo_bch_t* cm, * flt;
 	moo_oow_t len;
-	moo_traits_t trait, dbgopt = 0;
+	moo_bitmask_t trait, dbgopt = 0;
 
 	cm = str - 1;
 	do
@@ -2467,7 +2467,7 @@ int main (int argc, char* argv[])
 	}
 
 	{
-		moo_traits_t trait = 0;
+		moo_bitmask_t trait = 0;
 
 		/*trait |= MOO_NOGC;*/
 		trait |= MOO_AWAIT_PROCS;
diff --git a/moo/lib/moo.c b/moo/lib/moo.c
index 7e24b6b..9d9fd1e 100644
--- a/moo/lib/moo.c
+++ b/moo/lib/moo.c
@@ -291,14 +291,14 @@ int moo_setoption (moo_t* moo, moo_option_t id, const void* value)
 	switch (id)
 	{
 		case MOO_TRAIT:
-			moo->option.trait = *(moo_traits_t*)value;
+			moo->option.trait = *(moo_bitmask_t*)value;
 		#if defined(MOO_BUILD_DEBUG)
 			moo->option.karatsuba_cutoff = ((moo->option.trait & MOO_DEBUG_BIGINT)? MOO_KARATSUBA_CUTOFF_DEBUG: MOO_KARATSUBA_CUTOFF);
 		#endif
 			return 0;
 
 		case MOO_LOG_MASK:
-			moo->option.log_mask = *(moo_log_masks_t*)value;
+			moo->option.log_mask = *(moo_bitmask_t*)value;
 			return 0;
 
 		case MOO_LOG_MAXCAPA:
@@ -353,11 +353,11 @@ int moo_getoption (moo_t* moo, moo_option_t id, void* value)
 	switch  (id)
 	{
 		case MOO_TRAIT:
-			*(moo_traits_t*)value = moo->option.trait;
+			*(moo_bitmask_t*)value = moo->option.trait;
 			return 0;
 
 		case MOO_LOG_MASK:
-			*(moo_log_masks_t*)value = moo->option.log_mask;
+			*(moo_bitmask_t*)value = moo->option.log_mask;
 			return 0;
 
 		case MOO_LOG_MAXCAPA:
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index c606474..b0a7eed 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -38,6 +38,9 @@
  * object instead of putting in in a separate byte array. */
 #define MOO_USE_METHOD_TRAILER
 
+
+typedef unsigned int moo_bitmask_t;
+
 /* ========================================================================== */
 
 /**
@@ -128,8 +131,6 @@ enum moo_trait_t
 };
 typedef enum moo_trait_t moo_trait_t;
 
-typedef unsigned int moo_traits_t;
-
 typedef struct moo_obj_t           moo_obj_t;
 typedef struct moo_obj_t*          moo_oop_t;
 
@@ -949,8 +950,6 @@ enum moo_log_mask_t
 };
 typedef enum moo_log_mask_t moo_log_mask_t;
 
-typedef unsigned int moo_log_masks_t;
-
 /* all bits must be set to get enabled */
 #define MOO_LOG_ENABLED(moo,mask) (((moo)->option.log_mask & (mask)) == (mask))
 
@@ -1009,7 +1008,7 @@ typedef void (*moo_free_heap_t) (
 
 typedef void (*moo_log_write_t) (
 	moo_t*             moo,
-	moo_log_masks_t    mask,
+	moo_bitmask_t    mask,
 	const moo_ooch_t*  msg,
 	moo_oow_t          len
 );
@@ -1312,8 +1311,8 @@ struct moo_t
 
 	struct
 	{
-		moo_traits_t trait;
-		moo_log_masks_t log_mask;
+		moo_bitmask_t trait;
+		moo_bitmask_t log_mask;
 		moo_oow_t log_maxcapa;
 		moo_oow_t dfl_symtab_size;
 		moo_oow_t dfl_sysdic_size;
@@ -1337,8 +1336,8 @@ struct moo_t
 		moo_ooch_t* ptr;
 		moo_oow_t len;
 		moo_oow_t capa;
-		moo_log_masks_t last_mask;
-		moo_log_masks_t default_type_mask;
+		moo_bitmask_t last_mask;
+		moo_bitmask_t default_type_mask;
 	} log;
 
 	/* ========================= */