When I first encountered J's indeterminate (_.) I, too, was inclined to use it as a value by which "other", "unknown", "not applicable" and similar meanings might be handled. I quickly came to the opinion that this is not actually a good idea, however.
Indeterminate has a particular meaning. It means that where a numeric value might be expected, the actual result in hand is not a numeric value. It provides a special form of error message, one that can be handled programmatically. Much as I would like to have a special symbol for use as a special value, as in three-valued logic, attempting to use _. for that purpose undermines and contradicts its given meaning. If it comes to pass that for this purpose _.. or some other new primary becomes supported by the language, I'll be thrilled. Until then, I'm not going to try to make indeterminate into something it is not. Tracy ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
