I've been working on a new macro expander for Racket, and I'm starting to think that it will work. The new expander is not completely compatible with the current expander --- and that will be an issue if we eventually go forward with the change --- but most existing code still works.
Here's a report on my current experiment: http://www.cs.utah.edu/~mflatt/scope-sets/ The goals for a new expander are 1. to replace a complicated representation of syntax objects with a simpler one (and, as a result, avoid some performance and submodule-re-expansion problems that have been too difficult to fix with the current expander); 2. to find a simpler model of binding than the current one, so that it's easier to explain and reason about scope and macros; and 3. to implement the new expander in Racket instead of C. I have possibly succeeded on 1, possibly succeeded to some degree on 2, and temporarily given up on 3. (I know it sounds crazy to continue with a C implementation of macro expansion. Goals 1 and 2 were impossible for me without being able to try ideas at scale, though, and it was too daunting to tackle a full reimplementation of the expander and a restructuring of the VM at the same time. Continuing in the comfortable-for-only-me C environment was the way to make progress for now, and I look forward to tackling 3 as a next step.) I've pushed my current implementation to the "scope" branches of https://github.com/mflatt/racket https://github.com/mflatt/compiler [for `raco decompile` updates] I don't recommend bothering with the implementation, for now, unless you're especially interested in trying some examples. The current version builds well enough to run DrRacket, but there some build errors. I have a lot of work to do, still. -- You received this message because you are subscribed to the Google Groups "Racket Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-dev+unsubscr...@googlegroups.com. To post to this group, send email to racket-...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-dev/20150226172633.2725A6501AA%40mail-svr1.cs.utah.edu. For more options, visit https://groups.google.com/d/optout.
