For comparisons we have equal (=) and not equal (~:) and less than (<) and larger than (>). I ignore min (<.) and max (>.) and less or equal (<:) and larger or equal (>:) since I consider them as direct derivatives of < and >. Also match (-:) is ignored.
All four (=, ~:, < and >) have dyadic rank 0, but I am more interested in their differences, which, to me, are rather annoying. We get =/2 4 ?.@$ 2 0 0 1 1 for obvious reasons, and likewise with the 3 other verbs. But why is the next behavior different? =/;/2 4 ?.@$ 2 0 ~:/;/2 4 ?.@$ 2 1 </;/2 4 ?.@$ 2 |domain error | </;/2 4?.@$2 >/;/2 4 ?.@$ 2 |domain error | >/;/2 4?.@$2 Because we can compare the boxed items, as is shown by /: ;/2 4 ?.@$ 2 0 1 Needless to say also the other comparisons go wrong <./;/2 4 ?.@$ 2 |domain error | <./;/2 4?.@$2 <:/;/2 4 ?.@$ 2 |domain error | <:/;/2 4?.@$2 Of course I can circumvent the errors in one way or the other, e.g. by using /:, but usually that costs quite some performance. Is there any time soon that the techniques which are used to compare boxed atoms, like used in /: , will be used for < and > too? R.E Boss ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
