diff --git a/f.sh b/f.sh
index 30532d9..6986105 100644
--- a/f.sh
+++ b/f.sh
@@ -1,25 +1,41 @@
 #!/bin/sh
 
 alias :=_newword
-alias '(=:'
-alias ')=;'
+alias ']=_execbody'
+alias xshift='shift 2>/dev/null || printf "Stack underflow\n"'
 
 _stack="" # top is 
 _builtin_dictionary="swap dup rot over drop add sub div mod mul put" # + - / * .
-_dictionary=
 
 _newword() {
 	name="$1"
 	shift
-	export "\$${name}_definition=\"$*\""
+	eval "${name}_definition=\"$*\""
 }
 
 _execword() {
-	eval "def='$1_definition'"
-	for word in $def; do
+	eval "def=\"\$$1_definition\""
+	eval "def=\"\$$1_definition\""
+	[ "$def" ] || {
+		printf '%s\n' "Error: no word $1"
+		return
+	}
+	_execbody $def
+}
+
+_execbody() {
+	for word in "$@"; do
+		[ "$_debug" ] && {
+			printf 'word %s\nstack %s\n' "$word" "$_stack"
+			read
+		}
 		case "$_builtin_dictionary" in
-			*"$word"*)  "_$word" "$_stack" ;;
-			*) _execword "$word" ;;
+			*"$word"*) "_$word" $_stack ;;
+			*) case "$word" in
+				*[0-9]*)   _stack="$word $_stack" ;;
+				*)         _execword "$word" ;;
+			esac
+			;;
 		esac
 	done
 }
@@ -27,7 +43,7 @@ _execword() {
 _swap() {
 	one="$1"
 	two="$2"
-	shift
+	xshift
 	_stack="$2 $1 $*"
 }
 
@@ -39,7 +55,9 @@ _rot() {
 	one="$1"
 	two="$2"
 	thr="$3"
-	shift 3
+	xshift
+	xshift
+	xshift
 	_stack="$3 $1 $2 $*"
 }
 
@@ -48,48 +66,53 @@ _over() {
 }
 
 _drop() {
-	shift
+	xshift
 	_stack="$*"
 }
 
 _add() {
 	one="$1"
 	two="$2"
-	shift 2
+	xshift
+	xshift
 	_stack="$(( one + two )) $*"
 }
 
 _sub() {
 	one="$1"
 	two="$2"
-	shift 2
+	xshift
+	xshift
 	_stack="$(( two - one )) $*"
 }
 
 _div() {
 	one="$1"
 	two="$2"
-	shift 2
+	xshift
+	xshift
 	_stack="$(( two / one )) $*"
 }
 
 _mod() {
 	one="$1"
 	two="$2"
-	shift 2
+	xshift
+	xshift
 	_stack="$(( two % one )) $*"
 }
 
 _mul() {
 	one="$1"
 	two="$2"
-	shift 2
+	xshift
+	xshift
 	_stack="$(( one * two )) $*"
 }
 
 _put() {
 	one="$1"
-	shift
+	xshift
 	printf '%s \n' "$one"
 	_stack="$*"
 }