Using Parsec and Interfacing with C in Haskell

Parsing a file, or data of various types, is a common task for programmers. We already learned about Haskell's support for regular expressions back in "Regular Expressions in Haskell" on page 198. Regular expressions are nice for many tasks, but they rapidly become unwieldy, or cannot be used at all, when dealing with a complex data format. For instance, we cannot use regular expressions to parse source code from most programming languages.