SIGNATURE SeqSort[data]

-- functions related to sorting of sequences
-- Parameter

SORT data

IMPORT  Seq[data] ONLY seq

FUN msort: (data**data->bool)->seq[data]->seq[data]
           -- msort (<) (s) 
           -- merge sort of sequence s with respect to order <
           -- (should be used with a transitive and irreflexive order)

FUN merge: (data**data->bool)->seq[data]**seq[data]->seq[data] 
           -- merge (<) (s1, s2)
           -- merges two sequences s1 and s2  with respect to <
           -- provided that s1 and s2 are sorted with respect to <
           -- the result of merge is sorted too.