--- a/python/ppci/ir.py	Fri Dec 06 12:37:48 2013 +0100
+++ b/python/ppci/ir.py	Fri Dec 06 12:45:02 2013 +0100
@@ -237,10 +237,12 @@
 
 
 class Expression:
+    """ Base class for an expression """
     pass
 
 
 class Const(Expression):
+    """ Represents a constant value """
     def __init__(self, value):
         self.value = value
 
@@ -262,6 +264,7 @@
 
 # Data operations
 class Binop(Expression):
+    """ Generic binary operation """
     ops = ['+', '-', '*', '/', '|', '&', '<<', '>>']
     def __init__(self, value1, operation, value2):
         assert operation in Binop.ops
@@ -384,6 +387,7 @@
 
 
 class Jump(LastStatement):
+    """ Jump statement to some target location """
     def __init__(self, target):
         self.Targets = [target]