text: """
  Macros for simplifying construction of C programs.
  """
  
  from ctree.c.nodes import SymbolRef, CtreeNode, FunctionCall, String
  
  
  def NULL():
      """
      The NULL symbol.
      """
      return SymbolRef("NULL")
  
  
  def printf(fmt, *args):
      """
      Makes a printf call. Args must be CtreeNodes.
      """
      for arg in args:
          assert isinstance(arg, CtreeNode)
      return FunctionCall(SymbolRef("printf"),
                          [String(fmt)] + list(args))
  