--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/c3/semantics.py	Fri Mar 01 10:24:01 2013 +0100
@@ -0,0 +1,50 @@
+from . import astnodes
+
+class Scope:
+   """ A scope contains all symbols in a scope """
+   def __init__(self, parent=None):
+      self.symbols = {}
+      self.parent = parent
+   def getType(self, name):
+      t = self.getSymbol(name)
+      print(t)
+      assert isinstance(t, astnodes.Type)
+      return t
+   def getSymbol(self, name):
+      if name in self.symbols:
+         return self.symbols[name]
+      # Look for symbol:
+      if self.parent:
+         return self.parent.getSymbol(name)
+      raise CompilerException("Symbol {0} not found".format(name), name.loc)
+   def hasSymbol(self, name):
+      if name in self.symbols:
+         return True
+      if self.parent:
+         return self.parent.hasSymbol(name)
+      return False
+      
+   def addSymbol(self, sym):
+      self.symbols[sym.name] = sym
+
+def createBuiltins(scope):
+   scope.addSymbol(astnodes.BaseType('int'))
+
+class Semantics:
+   """ This class constructs the AST from parser input """
+   def __init__(self, diag):
+      self.diag = diag
+   def handlePackage(self, name, loc):
+      self.mod = astnodes.Package(name)
+      self.mod.loc = loc
+      self.mod.scope = self.curScope = Scope()
+      createBuiltins(self.curScope)
+   def handleBinop(self, lhs, op, rhs):
+      pass
+   def actOnLocal(self, t, name, ival):
+      s = astnodes.Variable(name, t, False)
+      self.curScope.addSymbol(s)
+   def actOnType(self, tok):
+      # Try to lookup type, in case of failure return void
+      pass
+