--- a/python/c3/typecheck.py	Tue Jul 09 17:59:15 2013 +0200
+++ b/python/c3/typecheck.py	Thu Jul 11 07:42:30 2013 +0200
@@ -34,19 +34,19 @@
         return self.ok
 
     def check2(self, sym):
-      if type(sym) in [IfStatement, WhileStatement]:
-         if not equalTypes(sym.condition.typ, boolType):
-            self.error('Condition must be of type {0}'.format(boolType), sym.condition.loc)
-      elif type(sym) is Assignment:
+        if type(sym) in [IfStatement, WhileStatement]:
+            if not equalTypes(sym.condition.typ, boolType):
+                self.error('Condition must be of type {0}'.format(boolType), sym.condition.loc)
+        elif type(sym) is Assignment:
             if not equalTypes(sym.lval.typ, sym.rval.typ):
                 self.error('Cannot assign {0} to {1}'.format(sym.rval.typ, sym.lval.typ), sym.loc)
             if not sym.lval.lvalue:
                 self.error('No valid lvalue {}'.format(sym.lval), sym.lval.loc)
             #if sym.rval.lvalue:
             #    self.error('Right hand side must be an rvalue', sym.rval.loc)
-      elif type(sym) is ReturnStatement:
-         pass
-      elif type(sym) is FunctionCall:
+        elif type(sym) is ReturnStatement:
+            pass
+        elif type(sym) is FunctionCall:
          if sym.proc:
             # Check arguments:
             ngiv = len(sym.args)
@@ -62,13 +62,14 @@
             sym.typ = sym.proc.typ.returntype
          else:
             sym.typ = intType
-      elif type(sym) is VariableUse:
+        elif type(sym) is VariableUse:
             sym.lvalue = True
-            if sym.target:
+            if type(sym.target) is Variable:
                 sym.typ = sym.target.typ
             else:
+                print('warning {} has no target, defaulting to int'.format(sym))
                 sym.typ = intType
-      elif type(sym) is Literal:
+        elif type(sym) is Literal:
             sym.lvalue = False
             if type(sym.val) is int:
                 sym.typ = intType
@@ -77,22 +78,35 @@
             elif type(sym.val) is bool:
                 sym.typ = boolType
             else:
-                self.error('Unknown literal type', sym.loc)
-      elif type(sym) is Unop:
+                raise Exception('Unknown literal type'.format(sym.val))
+        elif type(sym) is Unop:
             if sym.op == '&':
                 sym.typ = PointerType(sym.a.typ)
                 sym.lvalue = False
-            elif sym.op == '*':
-                # pointer deref
-                sym.lvalue = True
-                if type(sym.a.typ) is PointerType:
-                    sym.typ = sym.a.typ.ptype
+            else:
+                raise Exception('Unknown unop {0}'.format(sym.op))
+        elif type(sym) is Deref:
+            # pointer deref
+            sym.lvalue = True
+            # check if the to be dereferenced variable is a pointer type:
+            if type(sym.ptr.typ) is PointerType:
+                sym.typ = sym.ptr.typ.ptype
+            else:
+                self.error('Cannot dereference non-pointer type {}'.format(sym.ptr.typ), sym.loc)
+                sym.typ = intType
+        elif type(sym) is FieldRef:
+            basetype = sym.base.typ
+            sym.lvalue = True
+            if type(basetype) is StructureType:
+                if basetype.hasField(sym.field):
+                    sym.typ = basetype.fieldType(sym.field)
                 else:
+                    self.error('{} does not contain field {}'.format(basetype, symfield), sym.loc)
                     sym.typ = intType
-                    self.error('Cannot dereference non-pointer type {}'.format(sym.a.typ), sym.loc)
             else:
-                print('unknown unop', sym.op)
-      elif type(sym) is Binop:
+                self.error('Cannot select field {} of non-structure type {}'.format(sym.field, basetype), sym.loc)
+                sym.typ = intType
+        elif type(sym) is Binop:
          sym.lvalue = False
          if sym.op in ['+', '-', '*', '/']:
             if equalTypes(sym.a.typ, sym.b.typ):
@@ -104,11 +118,11 @@
             else:
                # assume void here? TODO: throw exception!
                sym.typ = intType
-               self.error('Types unequal', sym.loc)
+               self.error('Types unequal {} != {}'.format(sym.a.typ, sym.b.typ), sym.loc)
          elif sym.op in ['>', '<', '==', '<=', '>=']:
             sym.typ = boolType
             if not equalTypes(sym.a.typ, sym.b.typ):
-               self.error('Types unequal', sym.loc)
+               self.error('Types unequal {} != {}'.format(sym.a.typ, sym.b.typ), sym.loc)
          elif sym.op in ['or', 'and']:
             sym.typ = boolType
             if not equalTypes(sym.a.typ, boolType):
@@ -117,24 +131,24 @@
                self.error('Must be {0}'.format(boolType), sym.b.loc)
          elif sym.op in ['|', '&']:
                 sym.typ = intType
+                raise Exception('Not implemented')
                 # TODO: elaborate?
          else:
-            sym.typ = voidType
-            print('unknown binop', sym.op)
-      elif type(sym) is Variable:
+            raise Exception('Unknown binop {0}'.format(sym.op))
+        elif type(sym) is Variable:
          # check initial value type:
          # TODO
          pass
-      elif type(sym) is TypeCast:
+        elif type(sym) is TypeCast:
             if canCast(sym.a.typ, sym.to_type):
                 sym.typ = sym.to_type
             else:
                 self.error('Cannot cast {} to {}'.format(sym.a.typ, sym.to_type))
-      elif type(sym) is Constant:
-         if not equalTypes(sym.typ, sym.value.typ):
-            self.error('Cannot assign {0} to {1}'.format(sym.value.typ, sym.typ), sym.loc)
-      elif type(sym) in [EmptyStatement, CompoundStatement, Package, Function, FunctionType, ExpressionStatement]:
+        elif type(sym) is Constant:
+            if not equalTypes(sym.typ, sym.value.typ):
+                self.error('Cannot assign {0} to {1}'.format(sym.value.typ, sym.typ), sym.loc)
+        elif type(sym) in [EmptyStatement, CompoundStatement, Package, Function, FunctionType, ExpressionStatement, DefinedType]:
          pass
-      else:
+        else:
             raise Exception('Unknown type check {0}'.format(sym))