PythonにC++のconstみたいな、Javaのfinalみたいな修飾子を追加する…

パッチを書きました。

Python 2.6.5 (r265:79063, 魔改造, May  2 2010, 17:41:13) 
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
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>>> def a(): 
... 	readonly a = b = 3
... 	a = 3
... 
  File "<stdin>", line 3
SyntaxError: variable 'a' is read-only
>>> def a():
... 	x = 3
... 	readonly x = 3
... 
  File "<stdin>", line 3
SyntaxError: name 'x' is assigned to before readonly declaration
>>> def a():
... 	print x
... 	readonly x = 3
... 
  File "<stdin>", line 3
SyntaxError: name 'x' is used prior to readonly declaration

こんな感じで。どうでしょう。