ziv@2240: functor TripleKeyFn (structure I : ORD_KEY
ziv@2240:                      structure J : ORD_KEY
ziv@2240:                      structure K : ORD_KEY)
ziv@2240:         : ORD_KEY where type ord_key = I.ord_key * J.ord_key * K.ord_key = struct
ziv@2240: 
ziv@2240: type ord_key = I.ord_key * J.ord_key * K.ord_key
ziv@2240: 
ziv@2240: fun compare ((i1, j1, k1), (i2, j2, k2)) =
ziv@2240:     case I.compare (i1, i2) of
ziv@2240:         EQUAL => (case J.compare (j1, j2) of
ziv@2240:                       EQUAL => K.compare (k1, k2)
ziv@2240:                     | ord => ord)
ziv@2240:       | ord => ord
ziv@2240: 
ziv@2240: end