Need suggestion to speed up code...

[Roy Smith]

I need to split up a string into a list of fields.  The strings are value 
lists from SQL statements, and look something like this:

(1, 'foo', 'bar', 34, 3.14159, 'an imbedded comma, this sting has', 'this 
one isn''t so easy either')

If it wasn't for the fact that I need to handle commas and quotes imbedded 
in quoted strings, it would be trivial -- just a call to string.split.  
But, as it is, the best I can figure out is to walk the string, character 
by character, keeping track of what state I'm in (parsing an integer, 
parsing a floating point, or parsing a quoted string).  It works, but 
profiling shows it's the bottleneck in my whole program.

Anybody have any idea for a better way to do this?

If I really had to, I suppose I could write this bit in C as an extension 
module, but I'd rather do a pure python implementation to keep it portable.