Now that D. and D:have been freed of derivative duties, I suggest that they be given tree-depth duties.
I typically envision trees as bearing leaves at multiple "levels", which are, however, all labeled as 0 in J. The numbers of Opens needed to access each of them can be termed their "depths", and that value is more often of use to me than their J-levels. Since we often call these containers "trees", the distance from "root" to "leaf" would normally be termed "height" (for which H: or h. is available). I tend to think, instead, of nested boxes as "caverns", or "dungeons", requiring a specific set of keys (index list) for access to each cell--where there do, indeed, be Domain Dragons, waiting to pounce on a mixed-type Open. (It is safest to store only values of compatible type on any given level.) By analogy to the "level" verbs, D. and D: could become "Depth" (or "DepthOf") and "DepthAt" (or "AtDepth"). Since L. and L: are of different valences, a single symbol could suffice for their purposes--unless someone has visions for eventual related extensions. The same would be true for depth or height verbs. --Art ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
