I'd like to suggest that folks interested in this have a look at the languages J and K, both of which are discussed on comp.lang.apl.

J is designed by Ken Iverson (with help from Ken Hui and others). J is, it can therefore be argued, the latest version of APL. It is distinguished from APL by having an ascii-based representation, and a firmer and more extensive theoretical foundation, including a form of functional programming (called "tacit form") that seems very similar in spirit to Backus' FP. It also has recently been extended with OO capabilities. The system (including free trial versions) and more info are available at http://www.jsoftware.com.

The K language is also an APL-like language, similar in many respects to J, but it has grown within a business environment and has some very unique qualities. There is, as of very recently, a downloadable trial version of it, as well, at http://www.kx.com. It seems less mathematically oriented than J, but much more oriented towards business systems, and interprocess communication and rapid prototyping. There are ideas in the K system that totally blew me away (not so much the APL-like aspects, but the (apparently) total integration of language objects with user interface objects -- extremely neat stuff!).

Both systems, if you download them, come with extensive documentation. The K documents seem to be especially well written and accessible. There's a treasure trove of good, well thought out ideas in these systems, IMHO.

On Fri, 28 Aug 1998, Alan Kay wrote:

Maurice and Travis --

Dan Ingalls and I (seperately) were very taken with parts of APL in our youth, and. over the years, have been quite excited at the possibilities that polymorphism brings to this kind of generalization of collections. It is now time to take another pass at the algebraic roots of Smalltalk/Squeak. Suggestions please -- the best kind are not so much add-ons, but comprehensive schemes that are both powerful, readable, and help users think ...