Make it fast

[cdornan]

Apart from using fast backends very little effort has been applied to making the package efficient on the grounds that:

1. we want to get it right before making it fast and

2. the primary motivation is to make RE-based scripting in Haskell more attractive and many of those applications typically aren't performance sensitive (as the filters in the package used to process the literate Haskell programmes and generate the API modules are not performance sensitive).

As the dude says, if you need high-performance filters you should probably be writing them by hand — at least until this this issue has been fixed!