at-depth(depth, s) doesn’t work when the strategy s does not rewrite the current term to a leaf node

Submitted by Tobi Vollebregt on 27 October 2011 at 15:44

Here is a working at-depth:

at-depth’(s) =
?(0, ) < s + ?(d, ); all(<at-depth’(s)> ( d, ))

at-depth(s | depth) =
!(depth, );
at-depth’(s)

override at-depth(depth, s) =
at-depth(s | )