Tag Archives: regular expressions

Regular Expressions and Derivatives

When you’re working with regular languages specified in regular expression form, there’s a really cool idea that you can use for building regular expression matchers, and for describing how to convert from a regular expression to a NFA. It’s called the Brzozozwksi derivative of a regular expression – or just simply the derivative of a regexp.

The basic idea of the derivative is that given a regular expression, r, you can derive a new regular expression called the derivative with respect to symbol c, D_c(r). D_c(r) is a regular expression describing the string matched by r after it’s matched an r.

Continue reading