Dear all, After a few hectic months of hacking on guile-log to implement true undo/redo functionality to test out the ideas for my suggestion of srfi i'm glad to annonce guile-log v.0.3 https://gitorious.org/gule-log guile-log comes with two interfaces 1) kanren 2) guile-log native These are documented. The features of guile-log * A thorough rework of guarded variables, now guile-log is safe with respect to undo/redo. * Resurrection of the postpone code. * Accumulator like constructs. * zip like features. * most of kanren, e.g. especially the A* constructs. * most of prolog TODO: * explore multithreading. * improve the postpone interface. * tail call improvement. * implement prolog compiler e.g. introduce guile-prolog * introduce functional tree in stead of assoq in assoq mode. If you would like to have any feature included in guile-log, let me know. Happy Hacking.