Thomas Schilling wrote:
* Structural (optionally Type-Directed) Editing
Structural editing means that your code is always (mostly) syntactically correct, and in case of haskell maybe also type-checked. This also implies that edit operations have syntactic awareness. paredit[1] emulates this quite nicely for lisp, Proxima does something like this in Haskell for Haskell and XML-based languages. This also needs some way of incremental parsing, for which good techniques already exist[3].
Paredit doesn't just work for lisp. It works for almost all emacs modes, including e.g., haskell and perl (incidentally, I believe it works well for XML/SGML type stuff too). I use it regularly for various programming languages. Of course, it isn't perfect in a few respects, but it's pretty customisable and the author is responsive to ideas and questions. It's not type-directed, of course. Merely structural. But that alone is very handy. (Incidentally I agree with most of Thomas' points which I snipped, too) Jules