--- a/src/Pure/General/alist.ML Wed Oct 05 14:01:32 2005 +0200
+++ b/src/Pure/General/alist.ML Wed Oct 05 18:38:28 2005 +0200
@@ -9,6 +9,7 @@
signature ALIST =
sig
+ exception DUP
val lookup: ('a * 'b -> bool) -> ('b * 'c) list -> 'a -> 'c option
val defined: ('a * 'b -> bool) -> ('b * 'c) list -> 'a -> bool
val update: ('a * 'a -> bool) -> ('a * 'b)
@@ -20,12 +21,23 @@
val map_entry: ('a * 'b -> bool) -> 'a -> ('c -> 'c)
-> ('b * 'c) list -> ('b * 'c) list
val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
+ val merge: ('a * 'a -> bool) -> ('b * 'b -> bool)
+ -> ('a * 'b) list * ('a * 'b) list -> ('a * 'b) list (*exception DUP*)
val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
end;
structure AList: ALIST =
struct
+fun find_index eq xs key =
+ let
+ fun find [] _ = 0
+ | find ((key', value)::xs) i =
+ if eq (key, key')
+ then i
+ else find xs (i+1);
+ in find xs 1 end;
+
fun lookup _ [] _ = NONE
| lookup eq ((key, value)::xs) key' =
if eq (key', key) then SOME value
@@ -35,30 +47,44 @@
| defined eq ((key, value)::xs) key' =
eq (key', key) orelse defined eq xs key';
-fun update eq (key, value) xs =
+fun update eq (x as (key, value)) xs =
let
- fun upd ((x as (key', _))::xs) =
- if eq (key, key')
- then (key, value)::xs
- else x :: upd xs
- in if defined eq xs key then upd xs else (key, value)::xs end;
+ val i = find_index eq xs key;
+ fun upd 1 (_::xs) = (x::xs)
+ | upd i (x::xs) = x :: upd (i-1) xs;
+ in if i = 0 then x::xs else upd i xs end;
fun default eq (key, value) xs =
if defined eq xs key then xs else (key, value)::xs;
fun delete eq key xs =
let
- fun del ((x as (key', _))::xs) =
- if eq (key, key') then xs
- else x :: del xs;
- in if defined eq xs key then del xs else xs end;
+ val i = find_index eq xs key;
+ fun del 1 (_::xs) = xs
+ | del i (x::xs) = x :: del (i-1) xs;
+ in if i = 0 then xs else del i xs end;
+
+fun map_entry eq key f xs =
+ let
+ val i = find_index eq xs key;
+ fun mapp 1 ((x as (key, value))::xs) = (key, f value) :: xs
+ | mapp i (x::xs) = x :: mapp (i-1) xs;
+ in if i = 0 then xs else mapp i xs end;
-fun map_entry eq key' f xs =
+exception DUP;
+
+fun merge eq_key eq_val (xs, ys) =
let
- fun mapp ((x as (key, value))::xs) =
- if eq (key', key) then (key, f value)::xs
- else x :: mapp xs
- in if defined eq xs key' then mapp xs else xs end;
+ fun add (x as (key, value)) ys =
+ case lookup eq_key ys key
+ of NONE => update eq_key x ys
+ | SOME value' =>
+ if eq_val (value, value')
+ then ys
+ else raise DUP;
+ in
+ fold_rev add xs ys
+ end;
fun make keyfun =
let fun keypair x = (x, keyfun x)
@@ -67,7 +93,7 @@
fun find eq [] _ = []
| find eq ((key, value) :: xs) value' =
let
- val values = find eq xs value'
+ val values = find eq xs value';
in if eq (value', value) then key :: values else values end;
end;