Common Lisp is a lot, but compiling a LISP 1.5 is still a useful thing today. For one, LISP 1.5 (without PROG) is a subset (or can be made into one by changing some function names) of Common Lisp, elisp, ISLisp, EuLisp, PicoLisp (which is pretty much LISP 1.5, which is not stopping people from using it for large applications today), and a bunch of others.
Another thing LISP 1.5 is very useful for, and I would like to see more of, is as a simple model for memory management and other runtime algorithms. It makes algorithms both easy to understand and analyze, and obviously as this example shows makes them easy to implement! Henry Baker's amazing List Processing in Real Time on a Serial Computer[1] is probably the best example. If only all papers on garbage collection used a similar style.
Another thing LISP 1.5 is very useful for, and I would like to see more of, is as a simple model for memory management and other runtime algorithms. It makes algorithms both easy to understand and analyze, and obviously as this example shows makes them easy to implement! Henry Baker's amazing List Processing in Real Time on a Serial Computer[1] is probably the best example. If only all papers on garbage collection used a similar style.
[1] http://home.pipeline.com/~hbaker1/RealTimeGC.html