Interactive interpreter hooks

[Steven D'Aprano]

The sys module defines two hooks that are used in the interactive 
interpreter:

* sys.displayhook(value) gets called with the result of evaluating the 
line when you press ENTER;

* sys.excepthook(type, value, traceback) gets called with the details of 
the exception when your line raises an exception.

Is there a way to hook into the interactive interpreter *before* it is 
evaluated? That is, if I type "len([])" at the prompt and hit ENTER, I 
want a hook that runs before len([]) is evaluated to 0, so that I get the 
string "len([])".



-- 
Steven