plt/racket — pull request #362 by esilkensen (2013-06-06 20:31:21+00:00)
Title: 'traces' support for user-defined reduction relation applications

Add a new #:reduce argument to traces (and traces/ps) that defines the
function to use when applying the reduction relation. This way a
function could selectively display some subset of possible reduction
traces instead of all (e.g., a random one;
https://github.com/plt/racket/wiki/Redex-Features)