Rainer Joswig sent me a link to Back to the Future: Lisp as a Base for a Statistical Computing System. I haven't read it, but Rainer helpfully summarized it on comp.lang.lisp. Here's part of his summary:
These guys moved away from XLisp to languages like R. Now they feel that R has not a bright future as a implementation of an efficient programming language. Going back to XLisp is no option, since it is no longer used/maintained and also relatively 'slow'. The authors of the paper argue that by using Common Lisp:
- they can write more code in Lisp and less code in C. since Common Lisp implementations have a wider range of performance (due to providing optimizing, incremental, native code compilers) and the implementations are mostly written in Common Lisp themselves.
- they get the choice of several Common Lisp implementations that are maintained, so they don't have to maintain the language implementation.
- they get a standard language with features and extensions that XLisp does not provide or in a more primitive form. They don't have to maintain/invent their own programming language.
Their goal is to get an interactive system and reasonable performance at the same time - something that several Common Lisp implementations can provide.
His full article is here.