Useful RE patterns (was: Variable Interpolation - status of PEP215)

[Fredrik Lundh]

Pekka Niiranen wrote:
> Please make also example of recursive decent
> parser, for example LL(k)

regular expressions and parsers are two different things.

you can use regexps to implement the scanner part of a
parser (see e.g. http://effbot.org/guides/xml-scanner.htm),
but they quickly break down if you try to do something
more sophisticated.

</F>