The Text.Regex.DFA module provides a backend for regular expressions. To use it should be imported along with Text.Regex.Lazy. If you import this along with other backends, then you should do so with qualified imports, perhaps renamed for convenience.

The DFA engine now takes two CompOption flags: multiline and caseSensitive. These both default to True. The multiline option means that a dot matches everything except a newline and ^ and $ match the after and before a newlilne. If multiline is false then a dot matches everything and ^ and $ match only the start and end of the input. The ExecOption is a newtype'd ().

The DFA is a limited backend that trades off features for speed. It returns the longest full match, but does not return substring captures or allow back-references to be used. It has been expanded and can now handle the ^ and $ anchors. Internally it searches [Char] or ByteString, and is very suitable to quickly search either type.

The DFA backend is a derived work and under the LGPL, the details are in Text.Regex.DFA.Engine.