(* Title: Pure/General/table.ML
ID: $Id$
Author: Markus Wenzel and Stefan Berghofer, TU Muenchen
Generic tables and tables indexed by strings. Efficient purely
functional implementation using balanced 2-3 trees.
*)
signature KEY =
sig
type key
val ord: key * key -> order
end;
signature TABLE =
sig
type key
type 'a table
exception DUP of key
exception DUPS of key list
exception UNDEF of key
val empty: 'a table
val is_empty: 'a table -> bool
val map: ('a -> 'b) -> 'a table -> 'b table
val foldl: ('a * (key * 'b) -> 'a) -> 'a * 'b table -> 'a
val dest: 'a table -> (key * 'a) list
val keys: 'a table -> key list
val min_key: 'a table -> key option
val max_key: 'a table -> key option
val exists: (key * 'a -> bool) -> 'a table -> bool
val lookup: 'a table * key -> 'a option
val update: (key * 'a) * 'a table -> 'a table
val update_new: (key * 'a) * 'a table -> 'a table (*exception DUP*)
val map_entry: key -> ('a -> 'a) -> 'a table -> 'a table
val make: (key * 'a) list -> 'a table (*exception DUPS*)
val extend: 'a table * (key * 'a) list -> 'a table (*exception DUPS*)
val join: ('a * 'a -> 'a option) -> 'a table * 'a table -> 'a table (*exception DUPS*)
val merge: ('a * 'a -> bool) -> 'a table * 'a table -> 'a table (*exception DUPS*)
val delete: key -> 'a table -> 'a table (*exception UNDEF*)
val lookup_multi: 'a list table * key -> 'a list
val update_multi: (key * 'a) * 'a list table -> 'a list table
val make_multi: (key * 'a) list -> 'a list table
val dest_multi: 'a list table -> (key * 'a) list
val merge_multi: ('a * 'a -> bool) ->
'a list table * 'a list table -> 'a list table (*exception DUPS*)
val merge_multi': ('a * 'a -> bool) ->
'a list table * 'a list table -> 'a list table (*exception DUPS*)
end;
functor TableFun(Key: KEY): TABLE =
struct
(* datatype table *)
type key = Key.key;
datatype 'a table =
Empty |
Branch2 of 'a table * (key * 'a) * 'a table |
Branch3 of 'a table * (key * 'a) * 'a table * (key * 'a) * 'a table;
exception DUP of key;
exception DUPS of key list;
(* empty *)
val empty = Empty;
fun is_empty Empty = true
| is_empty _ = false;
(* map and fold combinators *)
fun map_table _ Empty = Empty
| map_table f (Branch2 (left, (k, x), right)) =
Branch2 (map_table f left, (k, f x), map_table f right)
| map_table f (Branch3 (left, (k1, x1), mid, (k2, x2), right)) =
Branch3 (map_table f left, (k1, f x1), map_table f mid, (k2, f x2), map_table f right);
fun foldl_table _ (x, Empty) = x
| foldl_table f (x, Branch2 (left, p, right)) =
foldl_table f (f (foldl_table f (x, left), p), right)
| foldl_table f (x, Branch3 (left, p1, mid, p2, right)) =
foldl_table f (f (foldl_table f (f (foldl_table f (x, left), p1), mid), p2), right);
fun dest tab = rev (foldl_table (fn (rev_ps, p) => p :: rev_ps) ([], tab));
fun keys tab = rev (foldl_table (fn (rev_ks, (k, _)) => k :: rev_ks) ([], tab));
fun exists P tab = foldl_table (fn (false, e) => P e | (b, _) => b) (false, tab);
fun min_key Empty = NONE
| min_key (Branch2 (left, (k, _), _)) = SOME (getOpt (min_key left, k))
| min_key (Branch3 (left, (k, _), _, _, _)) = SOME (getOpt (min_key left, k));
fun max_key Empty = NONE
| max_key (Branch2 (_, (k, _), right)) = SOME (getOpt (max_key right, k))
| max_key (Branch3 (_, _, _, (k,_), right)) = SOME (getOpt (max_key right, k));
(* lookup *)
fun lookup (Empty, _) = NONE
| lookup (Branch2 (left, (k, x), right), key) =
(case Key.ord (key, k) of
LESS => lookup (left, key)
| EQUAL => SOME x
| GREATER => lookup (right, key))
| lookup (Branch3 (left, (k1, x1), mid, (k2, x2), right), key) =
(case Key.ord (key, k1) of
LESS => lookup (left, key)
| EQUAL => SOME x1
| GREATER =>
(case Key.ord (key, k2) of
LESS => lookup (mid, key)
| EQUAL => SOME x2
| GREATER => lookup (right, key)));
(* updates *)
local
exception SAME;
datatype 'a growth =
Stay of 'a table |
Sprout of 'a table * (key * 'a) * 'a table;
fun modify key f tab =
let
fun modfy Empty = Sprout (Empty, (key, f NONE), Empty)
| modfy (Branch2 (left, p as (k, x), right)) =
(case Key.ord (key, k) of
LESS =>
(case modfy left of
Stay left' => Stay (Branch2 (left', p, right))
| Sprout (left1, q, left2) => Stay (Branch3 (left1, q, left2, p, right)))
| EQUAL => Stay (Branch2 (left, (k, f (SOME x)), right))
| GREATER =>
(case modfy right of
Stay right' => Stay (Branch2 (left, p, right'))
| Sprout (right1, q, right2) =>
Stay (Branch3 (left, p, right1, q, right2))))
| modfy (Branch3 (left, p1 as (k1, x1), mid, p2 as (k2, x2), right)) =
(case Key.ord (key, k1) of
LESS =>
(case modfy left of
Stay left' => Stay (Branch3 (left', p1, mid, p2, right))
| Sprout (left1, q, left2) =>
Sprout (Branch2 (left1, q, left2), p1, Branch2 (mid, p2, right)))
| EQUAL => Stay (Branch3 (left, (k1, f (SOME x1)), mid, p2, right))
| GREATER =>
(case Key.ord (key, k2) of
LESS =>
(case modfy mid of
Stay mid' => Stay (Branch3 (left, p1, mid', p2, right))
| Sprout (mid1, q, mid2) =>
Sprout (Branch2 (left, p1, mid1), q, Branch2 (mid2, p2, right)))
| EQUAL => Stay (Branch3 (left, p1, mid, (k2, f (SOME x2)), right))
| GREATER =>
(case modfy right of
Stay right' => Stay (Branch3 (left, p1, mid, p2, right'))
| Sprout (right1, q, right2) =>
Sprout (Branch2 (left, p1, mid), p2, Branch2 (right1, q, right2)))));
in
(case modfy tab of
Stay tab' => tab'
| Sprout br => Branch2 br)
handle SAME => tab
end;
in
fun update ((k, x), tab) = modify k (fn _ => x) tab;
fun update_new ((k, x), tab) = modify k (fn NONE => x | SOME _ => raise DUP k) tab;
fun map_entry k f = modify k (fn NONE => raise SAME | SOME x => f x);
end;
(* extend and make *)
fun extend (table, pairs) =
let
fun add ((tab, dups), (key, x)) =
(case lookup (tab, key) of
NONE => (update ((key, x), tab), dups)
| _ => (tab, key :: dups));
in
(case Library.foldl add ((table, []), pairs) of
(table', []) => table'
| (_, dups) => raise DUPS (rev dups))
end;
fun make pairs = extend (empty, pairs);
(* delete *)
exception UNDEF of key;
local
fun compare NONE (k2, _) = LESS
| compare (SOME k1) (k2, _) = Key.ord (k1, k2);
fun if_eq EQUAL x y = x
| if_eq _ x y = y;
fun del (SOME k) Empty = raise UNDEF k
| del NONE (Branch2 (Empty, p, Empty)) = (p, (true, Empty))
| del NONE (Branch3 (Empty, p, Empty, q, Empty)) =
(p, (false, Branch2 (Empty, q, Empty)))
| del k (Branch2 (Empty, p, Empty)) = (case compare k p of
EQUAL => (p, (true, Empty)) | _ => raise UNDEF (valOf k))
| del k (Branch3 (Empty, p, Empty, q, Empty)) = (case compare k p of
EQUAL => (p, (false, Branch2 (Empty, q, Empty)))
| _ => (case compare k q of
EQUAL => (q, (false, Branch2 (Empty, p, Empty)))
| _ => raise UNDEF (valOf k)))
| del k (Branch2 (l, p, r)) = (case compare k p of
LESS => (case del k l of
(p', (false, l')) => (p', (false, Branch2 (l', p, r)))
| (p', (true, l')) => (p', case r of
Branch2 (rl, rp, rr) =>
(true, Branch3 (l', p, rl, rp, rr))
| Branch3 (rl, rp, rm, rq, rr) => (false, Branch2
(Branch2 (l', p, rl), rp, Branch2 (rm, rq, rr)))))
| ord => (case del (if_eq ord NONE k) r of
(p', (false, r')) => (p', (false, Branch2 (l, if_eq ord p' p, r')))
| (p', (true, r')) => (p', case l of
Branch2 (ll, lp, lr) =>
(true, Branch3 (ll, lp, lr, if_eq ord p' p, r'))
| Branch3 (ll, lp, lm, lq, lr) => (false, Branch2
(Branch2 (ll, lp, lm), lq, Branch2 (lr, if_eq ord p' p, r'))))))
| del k (Branch3 (l, p, m, q, r)) = (case compare k q of
LESS => (case compare k p of
LESS => (case del k l of
(p', (false, l')) => (p', (false, Branch3 (l', p, m, q, r)))
| (p', (true, l')) => (p', (false, case (m, r) of
(Branch2 (ml, mp, mr), Branch2 _) =>
Branch2 (Branch3 (l', p, ml, mp, mr), q, r)
| (Branch3 (ml, mp, mm, mq, mr), _) =>
Branch3 (Branch2 (l', p, ml), mp, Branch2 (mm, mq, mr), q, r)
| (Branch2 (ml, mp, mr), Branch3 (rl, rp, rm, rq, rr)) =>
Branch3 (Branch2 (l', p, ml), mp, Branch2 (mr, q, rl), rp,
Branch2 (rm, rq, rr)))))
| ord => (case del (if_eq ord NONE k) m of
(p', (false, m')) =>
(p', (false, Branch3 (l, if_eq ord p' p, m', q, r)))
| (p', (true, m')) => (p', (false, case (l, r) of
(Branch2 (ll, lp, lr), Branch2 _) =>
Branch2 (Branch3 (ll, lp, lr, if_eq ord p' p, m'), q, r)
| (Branch3 (ll, lp, lm, lq, lr), _) =>
Branch3 (Branch2 (ll, lp, lm), lq,
Branch2 (lr, if_eq ord p' p, m'), q, r)
| (_, Branch3 (rl, rp, rm, rq, rr)) =>
Branch3 (l, if_eq ord p' p, Branch2 (m', q, rl), rp,
Branch2 (rm, rq, rr))))))
| ord => (case del (if_eq ord NONE k) r of
(q', (false, r')) =>
(q', (false, Branch3 (l, p, m, if_eq ord q' q, r')))
| (q', (true, r')) => (q', (false, case (l, m) of
(Branch2 _, Branch2 (ml, mp, mr)) =>
Branch2 (l, p, Branch3 (ml, mp, mr, if_eq ord q' q, r'))
| (_, Branch3 (ml, mp, mm, mq, mr)) =>
Branch3 (l, p, Branch2 (ml, mp, mm), mq,
Branch2 (mr, if_eq ord q' q, r'))
| (Branch3 (ll, lp, lm, lq, lr), Branch2 (ml, mp, mr)) =>
Branch3 (Branch2 (ll, lp, lm), lq, Branch2 (lr, p, ml), mp,
Branch2 (mr, if_eq ord q' q, r'))))));
in
fun delete k t = snd (snd (del (SOME k) t));
end;
(* join and merge *)
fun join f (table1, table2) =
let
fun add ((tab, dups), (key, x)) =
(case lookup (tab, key) of
NONE => (update ((key, x), tab), dups)
| SOME y =>
(case f (y, x) of
SOME z => (update ((key, z), tab), dups)
| NONE => (tab, key :: dups)));
in
(case foldl_table add ((table1, []), table2) of
(table', []) => table'
| (_, dups) => raise DUPS (rev dups))
end;
fun merge eq tabs = join (fn (y, x) => if eq (y, x) then SOME y else NONE) tabs;
(* tables with multiple entries per key (preserving order) *)
fun lookup_multi tab_key = getOpt (lookup tab_key,[]);
fun update_multi ((key, x), tab) = update ((key, x :: lookup_multi (tab, key)), tab);
fun make_multi pairs = foldr update_multi empty pairs;
fun dest_multi tab = List.concat (map (fn (key, xs) => map (Library.pair key) xs) (dest tab));
fun merge_multi eq tabs = join (fn (xs, xs') => SOME (gen_merge_lists eq xs xs')) tabs;
fun merge_multi' eq tabs = join (fn (xs, xs') => SOME (gen_merge_lists' eq xs xs')) tabs;
(*final declarations of this structure!*)
val map = map_table;
val foldl = foldl_table;
end;
(*tables indexed by strings*)
structure Symtab = TableFun(type key = string val ord = string_ord);