On Thu, 22 Jul 2004, David Steuber wrote:

These are just some idle questions.

Is the source from Hemlock at all useful as far as editing functions for porting over to a proper Carbon based application for an Aqua compliant IDE?

I had made some progress in integrating Portable Hemlock and Cocoa; I'd hoped to be able to release that a few months ago, but haven't had time to do much of anything OpenMCL- or mac-lisp-ide- related since.

I don't know how useful this would be to someone determined to use Carbon.

Hemlock is strongly oriented towards a model where a single "frame" (in the Emacs sense; this means something like "window" to the rest of the world) displays multiple buffers. I had tried to get things to fit better into the Mac "document" paradigm: so that there'd be roughly a 1:1 correspondence between a Hemlock buffer and a Mac document (and generally a single document per window.) I'd managed to nudge a lot of Hemlock towards the Mac paradigm, but there was still a lot of nudging to do (some Hemlock commands/functions still think that it's involved in redisplay and layout, and don't behave correctly under Cocoa.)

I think that it's fair to say that Hemlock's not very thread-aware, and some of the things that I did to try to make it behave better in a multi-window, multi-threaded environment are incredibly ugly. I suspect that many things have to be at least fairly ugly: "modal" things (like M-X and incremental search) want to block for input, but you don't really want the whole IDE to freeze because some window is waiting for the next incremental search character ...

As far as Hemlock itself goes ... I still think that it's easier than writing an editor core would have been, and it provides lots of support for S-expression-based navigation out-of-the-box. Aside from the whole "who's in charge of event-processing and redisplay" issues, the biggest piece of missing functionality that I can think of in the Hemlock code base is support for pattern-based searching (e.g., to be able to have M-. find a DEFUN or DEFMETHOD pattern without getting confused by case-sensitivity, whitespace, and other details.)

I think that most of the functionality that Hemlock provides is reasonable (if a bit spartan), and that the major difficulties with using Hemlock in a modern Aqua environment would be shared most other starting points (e.g., if you re-wrote [X]Emacs in CL, you'd still have to think about document/buffer/frame issues and threading and modality and ...).

If anyone wants to volunteer to fix up/finish the Hemlock/Cocoa stuff I started, I can help some; I hope to be able to work on it more in the near future, but every prediction I've made so far about how "near" has proven wildly optimistic.