I don't really like J but the only serious APL left is the proprietary (though free, and fun) Dyalog; K, the official product, is also proprietary and because Arthur rewrites it every couple of years all the open source clones are of different versions so there isn't much of an ecosystem.
I don't really like J but the only serious APL left is the proprietary (though free, and fun) Dyalog; K, the official product, is also proprietary and because Arthur rewrites it every couple of years all the open source clones are of different versions so there isn't much of an ecosystem.