Simple change of python's behaviour

[Tim Gahnström /Bladerman]

Hi,

I am creating an IDE in python for a python like language verry similar to
and based on the python interpreter

The first and most simple change I would like to do is to ad a construct /
keyword like this.

loop:
    do this for all eternity

this would be equivalent to

while true:
    do this for al eternity

What are your suggestions for the best aproach to this?
The most easy way, I start to feel is to do a little preprocessing where I
change all ocurrances of loop: to while true:

Another way would be to add loop as a native keyword in my python
interpreter, is it a feasible idea or is it just overworking something
simple? Where would I start for this?

Is there a better way?

Thanks

Tim