marked-up Python code

[Luc Goossens]

Hi,

I would like to experiment with marked-up Python source code. A more  
elaborate explanation of the use-case is at the end of this mail. The  
short story is that I would like to do things like assign colors to  
pieces of text in my editor and have this information saved _in my  
source  code_
smth like
<red>
else :
  print "ERROR"
  return -1
</red>

"all" the Python parser has to do is skip the mark-up.

Has something like this been done before? Is there a way  to do this  
without changing the Python executable? If not, where in the source  
code should I start looking?

cheers,
Luc

PS1
I know I can put the mark-up after a # and the problem is solved  
trivially, but this will not work for all cases (e.g. mark-up of  
single identifiers) and to be honest I was thinking of recycling some  
mark-up capable editor and an existing mark-up language

PS2
here's the real use case
I have a small application in Python. The code shares a recurring  
feature: within methods 20% of the code lines is about the actual  
handling of the correct case, 40% is about the handling of the  
incorrect cases, 40% is instrumenting (logging and timing).
A case for aspect oriented programming? I would certainly think so,  
but unfortunately  there is no obvious way to map this to the  
prevailing aspect-advice-joint point-point cut model. Moreover, I  
really do not want this code to become fragmented over multiple  
source code files, I just want the aspects to be readily visible in  
my editor, and be able to selectively show/hide some of them (like  
expanding/collapsing code blocks).