Seeing as how both Nimrod and D have invested into metaprogramming (and also "attempt a speed-elegance unification"), I think a comparison with D would be interesting. D doesn't have AST manipulation, though; the "parallel for" idiom is instead accomplished rather mundanely, using a custom iterator (http://dlang.org/phobos/std_parallelism.html#.TaskPool.paral...).

Another similarity is uniform call syntax (which D calls uniform function call syntax, UFCS for short).