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Diffstat (limited to 'src/multimap_fn.sml')
| -rw-r--r-- | src/multimap_fn.sml | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/multimap_fn.sml b/src/multimap_fn.sml new file mode 100644 index 00000000..3dab68a5 --- /dev/null +++ b/src/multimap_fn.sml @@ -0,0 +1,16 @@ +functor MultimapFn (structure KeyMap : ORD_MAP structure ValSet : ORD_SET) = struct + type key = KeyMap.Key.ord_key + type item = ValSet.item + type itemSet = ValSet.set + type multimap = ValSet.set KeyMap.map + val empty : multimap = KeyMap.empty + fun insertSet (kToVs : multimap, k : key, vs : itemSet) : multimap = + KeyMap.unionWith ValSet.union (kToVs, KeyMap.singleton (k, vs)) + fun insert (kToVs : multimap, k : key, v : item) : multimap = + insertSet (kToVs, k, ValSet.singleton v) + fun findSet (kToVs : multimap, k : key) = + case KeyMap.find (kToVs, k) of + SOME vs => vs + | NONE => ValSet.empty + val findList : multimap * key -> item list = ValSet.listItems o findSet +end |