diff --git a/tuned/profiles/functions/functions.py b/tuned/profiles/functions/functions.py
index 71bf112..68ce234 100644
--- a/tuned/profiles/functions/functions.py
+++ b/tuned/profiles/functions/functions.py
@@ -17,32 +17,73 @@ class Functions():
 
 	def __init__(self):
 		self._repository = repository.Repository()
+		self._parse_init()
 
-	def sub_func(self, mo):
-		sorig = mo.string[mo.start():mo.end()]
-		if mo.lastindex != 1:
-			return sorig
-		s = mo.string[mo.start(1):mo.end(1)]
-		if len(s) == 0:
-			return sorig
-		sl = re.split(r'(?<!\\):', s)
+	def _parse_init(self, s = ""):
+		self._cnt = 0
+		self._str = s
+		self._len = len(s)
+		self._stack = []
+		self._esc = False
+
+	def _curr_char(self):
+		return self._str[self._cnt]
+
+	def _curr_substr(self, _len):
+		return self._str[self._cnt:self._cnt + _len]
+
+	def _push_pos(self):
+		self._stack.append(self._cnt)
+
+	def _sub(self, a, b, s):
+		self._str = self._str[:a] + s + self._str[b + 1:]
+		self._len = len(self._str)
+		self._cnt += len(s) - (b - a + 1)
+		if self._cnt < 0:
+			self._cnt = 0
+
+	def _process_func(self, _from):
+		sl = re.split(r'(?<!\\):', self._str[_from:self._cnt])
+		if sl[0] != "${f":
+			return
 		sl = map(lambda v: str(v).replace("\:", ":"), sl)
-		if not re.match(r'\w+$', sl[0]):
-			log.error("invalid function name '%s'" % sl[0])
-			return sorig
+		if not re.match(r'\w+$', sl[1]):
+			log.error("invalid function name '%s'" % sl[1])
+			return
 		try:
-			f = self._repository.load_func(sl[0])
+			f = self._repository.load_func(sl[1])
 		except ImportError:
-			log.error("function '%s' not implemented" % sl[0])
-			return sorig
-		s = f.execute(sl[1:])
+			log.error("function '%s' not implemented" % sl[1])
+			return
+		s = f.execute(sl[2:])
 		if s is None:
-			return sorig
-		return s
+			return
+		self._sub(_from, self._cnt, s)
+
+	def _process(self, s):
+		self._parse_init(s)
+		while self._cnt < self._len:
+			if self._esc:
+				self._esc = False
+			else:
+				if self._curr_char() == "\\":
+					self._esc = True
+				elif self._curr_char() == "}":
+					try:
+						_from = self._stack.pop()
+					except IndexError:
+						log.error("invalid variable syntax, non pair '}' in: '%s'" % s)
+						return self._str
+					self._process_func(_from)
+				elif self._curr_substr(2) == "${":
+					self._push_pos()
+			self._cnt += 1
+		if len(self._stack):
+			log.error("invalid varialbe syntax, non pair '{' in: '%s'" % s)
+		return self._str
 
 	def expand(self, s):
-		if s is None:
+		if s is None or s == "":
 			return s
-		r = re.compile(r'(?<!\\)\${f:(.*)}')
 		# expand functions and convert all \${f:*} to ${f:*} (unescape)
-		return re.sub(r'\\(\${f:.*})', r'\1', r.sub(self.sub_func, s))
+		return re.sub(r'\\(\${f:.*\\})', r'\1', self._process(s))