The system is freely available from here . Do tell me if you know of similar results in the literature. The work of David Sands may be helpful here. I am also using this project to learn more about mechanised strength reduction, for instance the work of Yanhong Annie Liu . An extensible structure editor Tools that manipulate structured data, such as theorem provers or program transformation systems, need a convenient user interface.
Structure editors are ideal for the purpose.
I have been exploring the design and implementation of a structure editor in Haskell. It's very sparsely documented, so don't hesitate to ask me for advice if you want to play with it. Invited lectures at conferences International Summer School on Constructive Algorithmics 1989, 1992. IFIP WG 2.1 State of the Art Seminar on Formal Program Development, 1992. RelMiCS 2, 1995.