I tried something along those lines with a language called "radian", which was explicitly inspired by the Appel paper. I let the domain expire a while ago so al

I tried something along those lines with a language called "radian", which was explicitly inspired by the Appel paper. I let the domain expire a while ago so all the design discussion is gone, but you can see the remnants of the project here: http://www.github.com/marssaxman/radian.git http://www.github.com/marssaxman/radian.git It was not a strict subset of anything, but it was heavily inspired by Python. The goal was to constrain the language such that every for-loop could be decomposed into a map-reduce over an lazy iterator, so that the runtime could transparently schedule computation across all available cores. It all worked out well enough, and nothing feels more natural than coding in a language designed precisely to suit one's individual taste; but the idiosyncratic requirements of the memory and processor model meant there was very little opportunity to reuse existing library code, and I wound up spending most of my time on yak-shaving expeditions and getting very little done. I got around the mutable containers problem by not having any; the language included, as primitives, an ordered container based on finger trees and an associative container based on... hm... AVL trees maybe? It's been a while.