FSA Utilities
The FSA Utilities is an open-source software tool, written in Prolog, for creating, visualizing, and manipulating Finite state machines. It is useful for constructing finite-state machines from regular expressions and performing standard algorithms such as automata determinization, minimization, and intersection; transducer composition; etc. It includes algorithms for weighted and unweighted finite-state acceptors and transducers. It has a Tcl/TK graphical user interface which allows the user to view and manually manipulate the shapes of small automata and trandsucers. There is also a Prolog-based macro language which facilitates the construction of complex regular expressions.
The FSA Utilities is freely distributed by Gertjan van Noord under the GNU General Public License.