[IPython-User] Fiter input lines

[Alan Bromborsky]

I wish to be able to filter each line of input before python executes 
it.  From you documentation I know that this can be done, but I have 
been unable to find a simple example.  Could someone point me in the 
right direction.  Basically I have a function, addparen(input_str), that 
returns a constructs and returns a correct python string from input_str.