Add icon for interface.
(* Title: Pure/General/alist.ML
ID: $Id$
Author: Florian Haftmann, TU Muenchen
Association lists -- lists of (key, value) pairs with unique keys.
A light-weight representation of finite mappings;
see also Pure/General/table.ML for a more scalable implementation.
*)
signature ALIST =
sig
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)
-> ('a * 'b) list -> ('a * 'b) list
val default: ('a * 'a -> bool) -> ('a * 'b)
-> ('a * 'b) list -> ('a * 'b) list
val delete: ('a * 'b -> bool) -> 'a
-> ('b * 'c) list -> ('b * 'c) list
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 find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
end;
structure AList: ALIST =
struct
fun lookup _ [] _ = NONE
| lookup eq ((key, value)::xs) key' =
if eq (key', key) then SOME value
else lookup eq xs key';
fun defined _ [] _ = false
| defined eq ((key, value)::xs) key' =
eq (key', key) orelse defined eq xs key';
fun update eq (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;
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;
fun map_entry eq key' f xs =
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 make keyfun =
let fun keypair x = (x, keyfun x)
in map keypair end;
fun find eq [] _ = []
| find eq ((key, value) :: xs) value' =
let
val values = find eq xs value'
in if eq (value', value) then key :: values else values end;
end;