A List-machine Benchmark for Mechanized Metatheory by Andrew W. Appel and Xavier Leroy This is a Twelf solution to the benchmark, with proofs removed as an exercise for the reader. Start with sources.cfg. See also: http://www.inria.fr/rrrt/rr-5914.html http://www.cs.princeton.edu/~appel/listmachine/ http://gallium.inria.fr/~xleroy/listmachine/