diff --git a/gerlang.py b/gerlang.py
index 25320a0..dd2e62a 100644
--- a/gerlang.py
+++ b/gerlang.py
@@ -30,11 +30,17 @@ class StringAnalyzer(Analyzer):
 
 class TokenListAnalyzer(Analyzer):
 	def takeUntilType(self,end):
+		return self.takeUntil(lambda t: t[0] == end)
+
+	def takeUntil(self,condition, dropEnd=True):
 		t = []
-		while self.next() is not None and self.next()[0] != end: 
+		while self.next() is not None and not condition(self.next()): 
 			t.append( self.take() )
+		if dropEnd and self.next() is not None:
+			self.take()
 		return t
 
+
 class Lexer:
 	keywords = ["setze","auf","durch","schreibe"]
 	operators = ["plus","minus","mal","geteilt"]
@@ -51,6 +57,7 @@ class Lexer:
 		tokens = []
 		sa = StringAnalyzer(source)
 		braces = 0
+		stack = 0
 		while len(sa) != 0:
 			if sa.between('a', 'z') or sa.between('A', 'Z'): #identifier or keyword
 				ident = ""
@@ -60,6 +67,12 @@ class Lexer:
 					tokens.append( (self.KEYWORD,ident.lower()) )
 				elif ident.lower() in self.operators:
 					tokens.append( (self.OP,ident.lower()) )
+				elif ident.lower() == "wenn":
+					tokens.append( ( self.KEYWORD, "wenn", stack ) )
+					stack += 1
+				elif ident.lower() == "ende":
+					stack -= 1
+					tokens.append( ( self.KEYWORD, "ende", stack ) )
 				else:
 					tokens.append( (self.IDENT,ident) )
 			elif sa.between('0', '9'): #number
@@ -108,25 +121,34 @@ class Parser:
 					if ta.next()[0] != Lexer.KEYWORD or ta.next()[1] != "auf":
 						raise ParserException("missing auf after identifier")
 					ta.take()
-					term = self.__parseTerm(ta.takeUntilType(Lexer.NEWLINE))
-					ta.take()
+					term = self.__parseTerm(ta.takeUntil(lambda t: t[0] == Lexer.NEWLINE))
 					block.append(AssignmentTerm(ident,term))
 				elif ta.next()[1] == "schreibe":
 					ta.take()
 					term = self.__parseTerm(ta.takeUntilType(Lexer.NEWLINE))
 					block.append(PrintTerm(term))
+				elif ta.next()[1] == "wenn":
+					stack = ta.next()[2]
+					ta.take()
+					condition = ta.takeUntil(lambda t: t[0] == Lexer.NEWLINE)
+					b = ta.takeUntil(lambda t: t[0] == Lexer.KEYWORD and t[1] == "ende" and t[2] == stack)
+					block.append( ConditionalTerm(self.__parseTerm(condition), self.parse(b) ) )
+				else:
+					raise Exception("what? %s" % str(ta.next()))
 			elif ta.next()[0] == Lexer.NEWLINE:
 				ta.take()
+			else:
+				raise Exception("huh? %s" % str(ta.next()))
  		return block
 
 	def __parseTerm(self,tokens):
 		t = tokens[0]
-		if t[0] == Lexer.IDENT:
-			return IdentifierTerm(t[1])
-		elif t[0] == Lexer.INT or t[0] == Lexer.FLOAT:
+		if t[0] == Lexer.INT or t[0] == Lexer.FLOAT:
 			return ValueTerm(t[1])
+		elif t[0] == Lexer.IDENT:
+			return IdentifierTerm(t[1])
 		else:
-			raise ParseException("Unexpected token %s" % t)
+			return ValueTerm(0)
 
 class Context():
 	pass
@@ -134,10 +156,23 @@ class Context():
 class SubContext(Context):
 	pass
 
-class Term:
+class Term(object):
 	def run(self,context):
 		raise Exception("get_value must be overwritten")
 
+class Operator2(Term):
+	token = None
+	priority = 0
+	def __init__(self, left, right):
+		self.left = left
+		self.right = right
+
+	def run(self,context):
+		return self.calc( self.left.run(context), self.right.run(context) )
+
+	def calc(self, r, l):
+		raise Exception("calc not implemented")
+
 class IdentifierTerm:
 	def __init__(self, ident):
 		self.ident = ident
@@ -169,6 +204,17 @@ class PrintTerm(Term):
 		print self.term.run(context)
 		return None
 
+class ConditionalTerm(Term):
+	def __init__(self,condition,block):
+		self.condition = condition
+		self.block = block
+
+	def run(self,context):
+		m = self.condition.run(context)
+		if m != 0:
+			self.block.run(context)
+
+
 class BlockTerm(Term):
 	def __init__(self):
 		self.terms = []
@@ -186,12 +232,9 @@ def main():
 	context = {}
 	while True:
 		code = raw_input(">>> ")
-		try:
-			tokens = Lexer().lex(code)
-			term = Parser().parse(tokens)
-			term.run(context)
-		except Exception, e:
-			print e
+		tokens = Lexer().lex(code)
+		term = Parser().parse(tokens)
+		term.run(context)
 
 if __name__ == '__main__':
 	main()
\ No newline at end of file