How do you match only valid roman numerals with a regular expression?

Question

Thinking about my other problem, i decided I can\'t even create a regular expression that will match roman numerals (let alone a context-free grammar that will generate them

Answer 1

As Jeremy and Pax pointed out above ... '^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$' should be the solution you're after ...

The specific URL that should have been attached (IMHO) is http://thehazeltree.org/diveintopython/7.html

Example 7.8 is the short form using {n,m}