diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/list_key_fn.sml | 14 | ||||
| -rw-r--r-- | src/pair_key_fn.sml | 12 |
2 files changed, 26 insertions, 0 deletions
diff --git a/src/list_key_fn.sml b/src/list_key_fn.sml new file mode 100644 index 00000000..ec2bd26f --- /dev/null +++ b/src/list_key_fn.sml @@ -0,0 +1,14 @@ +functor ListKeyFn(K : ORD_KEY) + : ORD_KEY where type ord_key = K.ord_key list = struct + +type ord_key = K.ord_key list + +val rec compare = + fn ([], []) => EQUAL + | ([], _) => LESS + | (_, []) => GREATER + | (x::xs, y::ys) => case K.compare (x, y) of + EQUAL => compare (xs, ys) + | ord => ord + +end diff --git a/src/pair_key_fn.sml b/src/pair_key_fn.sml new file mode 100644 index 00000000..cd33950d --- /dev/null +++ b/src/pair_key_fn.sml @@ -0,0 +1,12 @@ +functor PairKeyFn (structure I : ORD_KEY + structure J : ORD_KEY) + : ORD_KEY where type ord_key = I.ord_key * J.ord_key = struct + +type ord_key = I.ord_key * J.ord_key + +fun compare ((i1, j1), (i2, j2)) = + case I.compare (i1, i2) of + EQUAL => J.compare (j1, j2) + | ord => ord + +end |