(* Title: Pure/library.ML
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Author: Markus Wenzel, TU Muenchen
Basic library: functions, pairs, booleans, lists, integers,
strings, lists as sets, orders, current directory, misc.
See also General/basics.ML for the most fundamental concepts.
*)
infix 2 ?
infix 3 o oo ooo oooo
infix 4 ~~ upto downto
infix orf andf \ \\ mem mem_int mem_string union union_int
union_string inter inter_int inter_string subset subset_int subset_string
signature BASIC_LIBRARY =
sig
(*functions*)
val undefined: 'a -> 'b
val I: 'a -> 'a
val K: 'a -> 'b -> 'a
val curry: ('a * 'b -> 'c) -> 'a -> 'b -> 'c
val uncurry: ('a -> 'b -> 'c) -> 'a * 'b -> 'c
val ? : bool * ('a -> 'a) -> 'a -> 'a
val oo: ('a -> 'b) * ('c -> 'd -> 'a) -> 'c -> 'd -> 'b
val ooo: ('a -> 'b) * ('c -> 'd -> 'e -> 'a) -> 'c -> 'd -> 'e -> 'b
val oooo: ('a -> 'b) * ('c -> 'd -> 'e -> 'f -> 'a) -> 'c -> 'd -> 'e -> 'f -> 'b
val funpow: int -> ('a -> 'a) -> 'a -> 'a
(*errors*)
exception SYS_ERROR of string
val sys_error: string -> 'a
exception ERROR of string
val error: string -> 'a
val cat_error: string -> string -> 'a
val assert_all: ('a -> bool) -> 'a list -> ('a -> string) -> unit
(*pairs*)
val pair: 'a -> 'b -> 'a * 'b
val rpair: 'a -> 'b -> 'b * 'a
val fst: 'a * 'b -> 'a
val snd: 'a * 'b -> 'b
val eq_fst: ('a * 'c -> bool) -> ('a * 'b) * ('c * 'd) -> bool
val eq_snd: ('b * 'd -> bool) -> ('a * 'b) * ('c * 'd) -> bool
val eq_pair: ('a * 'c -> bool) -> ('b * 'd -> bool) -> ('a * 'b) * ('c * 'd) -> bool
val swap: 'a * 'b -> 'b * 'a
val apfst: ('a -> 'b) -> 'a * 'c -> 'b * 'c
val apsnd: ('a -> 'b) -> 'c * 'a -> 'c * 'b
val pairself: ('a -> 'b) -> 'a * 'a -> 'b * 'b
(*booleans*)
val equal: ''a -> ''a -> bool
val not_equal: ''a -> ''a -> bool
val orf: ('a -> bool) * ('a -> bool) -> 'a -> bool
val andf: ('a -> bool) * ('a -> bool) -> 'a -> bool
val exists: ('a -> bool) -> 'a list -> bool
val forall: ('a -> bool) -> 'a list -> bool
val set: bool ref -> bool
val reset: bool ref -> bool
val toggle: bool ref -> bool
val change: 'a ref -> ('a -> 'a) -> unit
val change_result: 'a ref -> ('a -> 'b * 'a) -> 'b
val setmp_noncritical: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
val setmp: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
val setmp_thread_data: 'a Universal.tag -> 'a -> 'a -> ('b -> 'c) -> 'b -> 'c
(*lists*)
exception UnequalLengths
val single: 'a -> 'a list
val the_single: 'a list -> 'a
val singleton: ('a list -> 'b list) -> 'a -> 'b
val yield_singleton: ('a list -> 'c -> 'b list * 'c) -> 'a -> 'c -> 'b * 'c
val apply: ('a -> 'a) list -> 'a -> 'a
val perhaps_apply: ('a -> 'a option) list -> 'a -> 'a option
val perhaps_loop: ('a -> 'a option) -> 'a -> 'a option
val foldl1: ('a * 'a -> 'a) -> 'a list -> 'a
val foldr1: ('a * 'a -> 'a) -> 'a list -> 'a
val foldl_map: ('a * 'b -> 'a * 'c) -> 'a * 'b list -> 'a * 'c list
val flat: 'a list list -> 'a list
val unflat: 'a list list -> 'b list -> 'b list list
val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
val burrow_options: ('a list -> 'b list) -> 'a option list -> 'b option list
val burrow_fst: ('a list -> 'b list) -> ('a * 'c) list -> ('b * 'c) list
val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
val maps: ('a -> 'b list) -> 'a list -> 'b list
val filter: ('a -> bool) -> 'a list -> 'a list
val filter_out: ('a -> bool) -> 'a list -> 'a list
val map_filter: ('a -> 'b option) -> 'a list -> 'b list
val chop: int -> 'a list -> 'a list * 'a list
val dropwhile: ('a -> bool) -> 'a list -> 'a list
val nth: 'a list -> int -> 'a
val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
val nth_drop: int -> 'a list -> 'a list
val nth_list: 'a list list -> int -> 'a list
val map_index: (int * 'a -> 'b) -> 'a list -> 'b list
val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
val split_last: 'a list -> 'a list * 'a
val find_index: ('a -> bool) -> 'a list -> int
val find_index_eq: ''a -> ''a list -> int
val find_first: ('a -> bool) -> 'a list -> 'a option
val get_index: ('a -> 'b option) -> 'a list -> (int * 'b) option
val get_first: ('a -> 'b option) -> 'a list -> 'b option
val eq_list: ('a * 'b -> bool) -> 'a list * 'b list -> bool
val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
val zip_options: 'a list -> 'b option list -> ('a * 'b) list
val ~~ : 'a list * 'b list -> ('a * 'b) list
val map_split: ('a -> 'b * 'c) -> 'a list -> 'b list * 'c list
val split_list: ('a * 'b) list -> 'a list * 'b list
val map_product: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
val fold_product: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
val separate: 'a -> 'a list -> 'a list
val surround: 'a -> 'a list -> 'a list
val replicate: int -> 'a -> 'a list
val is_prefix: ('a * 'a -> bool) -> 'a list -> 'a list -> bool
val take_prefix: ('a -> bool) -> 'a list -> 'a list * 'a list
val chop_prefix: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list * ('a list * 'b list)
val take_suffix: ('a -> bool) -> 'a list -> 'a list * 'a list
val prefixes1: 'a list -> 'a list list
val prefixes: 'a list -> 'a list list
val suffixes1: 'a list -> 'a list list
val suffixes: 'a list -> 'a list list
(*integers*)
val inc: int ref -> int
val dec: int ref -> int
val upto: int * int -> int list
val downto: int * int -> int list
val radixpand: int * int -> int list
val radixstring: int * string * int -> string
val string_of_int: int -> string
val signed_string_of_int: int -> string
val string_of_indexname: string * int -> string
val read_radix_int: int -> string list -> int * string list
val read_int: string list -> int * string list
val oct_char: string -> string
(*strings*)
val nth_string: string -> int -> string
val fold_string: (string -> 'a -> 'a) -> string -> 'a -> 'a
val exists_string: (string -> bool) -> string -> bool
val forall_string: (string -> bool) -> string -> bool
val first_field: string -> string -> (string * string) option
val enclose: string -> string -> string -> string
val unenclose: string -> string
val quote: string -> string
val space_implode: string -> string list -> string
val commas: string list -> string
val commas_quote: string list -> string
val cat_lines: string list -> string
val space_explode: string -> string -> string list
val split_lines: string -> string list
val prefix_lines: string -> string -> string
val prefix: string -> string -> string
val suffix: string -> string -> string
val unprefix: string -> string -> string
val unsuffix: string -> string -> string
val replicate_string: int -> string -> string
val translate_string: (string -> string) -> string -> string
val multiply: 'a list -> 'a list list -> 'a list list
val match_string: string -> string -> bool
(*lists as sets -- see also Pure/General/ord_list.ML*)
val member: ('b * 'a -> bool) -> 'a list -> 'b -> bool
val insert: ('a * 'a -> bool) -> 'a -> 'a list -> 'a list
val remove: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
val update: ('a * 'a -> bool) -> 'a -> 'a list -> 'a list
val subtract: ('b * 'a -> bool) -> 'b list -> 'a list -> 'a list
val merge: ('a * 'a -> bool) -> 'a list * 'a list -> 'a list
val mem: ''a * ''a list -> bool
val mem_int: int * int list -> bool
val mem_string: string * string list -> bool
val union: ''a list * ''a list -> ''a list
val union_int: int list * int list -> int list
val union_string: string list * string list -> string list
val gen_union: ('a * 'a -> bool) -> 'a list * 'a list -> 'a list
val gen_inter: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list
val inter: ''a list * ''a list -> ''a list
val inter_int: int list * int list -> int list
val inter_string: string list * string list -> string list
val subset: ''a list * ''a list -> bool
val subset_int: int list * int list -> bool
val subset_string: string list * string list -> bool
val eq_set: ''a list * ''a list -> bool
val eq_set_string: string list * string list -> bool
val gen_subset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
val gen_eq_set: ('a * 'b -> bool) -> 'a list * 'b list -> bool
val \ : ''a list * ''a -> ''a list
val \\ : ''a list * ''a list -> ''a list
val distinct: ('a * 'a -> bool) -> 'a list -> 'a list
val duplicates: ('a * 'a -> bool) -> 'a list -> 'a list
val has_duplicates: ('a * 'a -> bool) -> 'a list -> bool
(*lists as multisets*)
val remove1: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
val submultiset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
(*orders*)
val is_equal: order -> bool
val rev_order: order -> order
val make_ord: ('a * 'a -> bool) -> 'a * 'a -> order
val bool_ord: bool * bool -> order
val int_ord: int * int -> order
val string_ord: string * string -> order
val fast_string_ord: string * string -> order
val option_ord: ('a * 'b -> order) -> 'a option * 'b option -> order
val prod_ord: ('a * 'b -> order) -> ('c * 'd -> order) -> ('a * 'c) * ('b * 'd) -> order
val dict_ord: ('a * 'b -> order) -> 'a list * 'b list -> order
val list_ord: ('a * 'b -> order) -> 'a list * 'b list -> order
val sort: ('a * 'a -> order) -> 'a list -> 'a list
val sort_distinct: ('a * 'a -> order) -> 'a list -> 'a list
val sort_strings: string list -> string list
val sort_wrt: ('a -> string) -> 'a list -> 'a list
(*random numbers*)
exception RANDOM
val random: unit -> real
val random_range: int -> int -> int
val one_of: 'a list -> 'a
val frequency: (int * 'a) list -> 'a
(*misc*)
val divide_and_conquer: ('a -> 'a list * ('b list -> 'b)) -> 'a -> 'b
val partition_eq: ('a * 'a -> bool) -> 'a list -> 'a list list
val partition_list: (int -> 'a -> bool) -> int -> int -> 'a list -> 'a list list
val gensym: string -> string
type stamp
val stamp: unit -> stamp
type serial
val serial: unit -> serial
val serial_string: unit -> string
structure Object: sig type T end
end;
signature LIBRARY =
sig
include BASIC_LIBRARY
val foldl: ('a * 'b -> 'a) -> 'a * 'b list -> 'a
val foldr: ('a * 'b -> 'b) -> 'a list * 'b -> 'b
val take: int * 'a list -> 'a list
val drop: int * 'a list -> 'a list
val last_elem: 'a list -> 'a
end;
structure Library: LIBRARY =
struct
(* functions *)
fun undefined _ = raise Match;
fun I x = x;
fun K x = fn _ => x;
fun curry f x y = f (x, y);
fun uncurry f (x, y) = f x y;
(*conditional application*)
fun b ? f = fn x => if b then f x else x;
(*composition with multiple args*)
fun (f oo g) x y = f (g x y);
fun (f ooo g) x y z = f (g x y z);
fun (f oooo g) x y z w = f (g x y z w);
(*function exponentiation: f(...(f x)...) with n applications of f*)
fun funpow (0: int) _ x = x
| funpow n f x = funpow (n - 1) f (f x);
(* errors *)
exception SYS_ERROR of string;
fun sys_error msg = raise SYS_ERROR msg;
exception ERROR of string;
fun error msg = raise ERROR msg;
fun cat_error "" msg = error msg
| cat_error msg1 msg2 = error (msg1 ^ "\n" ^ msg2);
fun assert_all pred list msg =
let
fun ass [] = ()
| ass (x :: xs) = if pred x then ass xs else error (msg x);
in ass list end;
(* pairs *)
fun pair x y = (x, y);
fun rpair x y = (y, x);
fun fst (x, y) = x;
fun snd (x, y) = y;
fun eq_fst eq ((x1, _), (x2, _)) = eq (x1, x2);
fun eq_snd eq ((_, y1), (_, y2)) = eq (y1, y2);
fun eq_pair eqx eqy ((x1, y1), (x2, y2)) = eqx (x1, x2) andalso eqy (y1, y2);
fun swap (x, y) = (y, x);
fun apfst f (x, y) = (f x, y);
fun apsnd f (x, y) = (x, f y);
fun pairself f (x, y) = (f x, f y);
(* booleans *)
(*polymorphic equality*)
fun equal x y = x = y;
fun not_equal x y = x <> y;
(*combining predicates*)
fun p orf q = fn x => p x orelse q x;
fun p andf q = fn x => p x andalso q x;
val exists = List.exists;
val forall = List.all;
(* flags *)
fun set flag = (flag := true; true);
fun reset flag = (flag := false; false);
fun toggle flag = (flag := not (! flag); ! flag);
fun change r f = r := f (! r);
fun change_result r f = let val (x, y) = f (! r) in r := y; x end;
(*temporarily set flag during execution*)
fun setmp_noncritical flag value f x =
uninterruptible (fn restore_attributes => fn () =>
let
val orig_value = ! flag;
val _ = flag := value;
val result = Exn.capture (restore_attributes f) x;
val _ = flag := orig_value;
in Exn.release result end) ();
fun setmp flag value f x =
NAMED_CRITICAL "setmp" (fn () => setmp_noncritical flag value f x);
fun setmp_thread_data tag orig_data data f x =
uninterruptible (fn restore_attributes => fn () =>
let
val _ = Thread.setLocal (tag, data);
val result = Exn.capture (restore_attributes f) x;
val _ = Thread.setLocal (tag, orig_data);
in Exn.release result end) ();
(** lists **)
exception UnequalLengths;
fun single x = [x];
fun the_single [x] = x
| the_single _ = raise Empty;
fun singleton f x = the_single (f [x]);
fun yield_singleton f x = f [x] #>> the_single;
fun apply [] x = x
| apply (f :: fs) x = apply fs (f x);
fun perhaps_apply funs arg =
let
fun app [] res = res
| app (f :: fs) (changed, x) =
(case f x of
NONE => app fs (changed, x)
| SOME x' => app fs (true, x'));
in (case app funs (false, arg) of (false, _) => NONE | (true, arg') => SOME arg') end;
fun perhaps_loop f arg =
let
fun loop (changed, x) =
(case f x of
NONE => (changed, x)
| SOME x' => loop (true, x'));
in (case loop (false, arg) of (false, _) => NONE | (true, arg') => SOME arg') end;
(* fold -- old versions *)
(*the following versions of fold are designed to fit nicely with infixes*)
(* (op @) (e, [x1, ..., xn]) ===> ((e @ x1) @ x2) ... @ xn
for operators that associate to the left (TAIL RECURSIVE)*)
fun foldl (f: 'a * 'b -> 'a) : 'a * 'b list -> 'a =
let fun itl (e, []) = e
| itl (e, a::l) = itl (f(e, a), l)
in itl end;
(* (op @) ([x1, ..., xn], e) ===> x1 @ (x2 ... @ (xn @ e))
for operators that associate to the right (not tail recursive)*)
fun foldr f (l, e) =
let fun itr [] = e
| itr (a::l) = f(a, itr l)
in itr l end;
(* (op @) [x1, ..., xn] ===> ((x1 @ x2) @ x3) ... @ xn
for operators that associate to the left (TAIL RECURSIVE)*)
fun foldl1 f [] = raise Empty
| foldl1 f (x :: xs) = foldl f (x, xs);
(* (op @) [x1, ..., xn] ===> x1 @ (x2 ... @ (x[n-1] @ xn))
for n > 0, operators that associate to the right (not tail recursive)*)
fun foldr1 f [] = raise Empty
| foldr1 f l =
let fun itr [x] = x
| itr (x::l) = f(x, itr l)
in itr l end;
fun foldl_map f =
let
fun fold_aux (x, []) = (x, [])
| fold_aux (x, y :: ys) =
let
val (x', y') = f (x, y);
val (x'', ys') = fold_aux (x', ys);
in (x'', y' :: ys') end;
in fold_aux end;
(* basic list functions *)
fun eq_list eq (list1, list2) =
let
fun eq_lst (x :: xs, y :: ys) = eq (x, y) andalso eq_lst (xs, ys)
| eq_lst _ = true;
in length list1 = length list2 andalso eq_lst (list1, list2) end;
fun maps f [] = []
| maps f (x :: xs) = f x @ maps f xs;
val filter = List.filter;
fun filter_out f = filter (not o f);
val map_filter = List.mapPartial;
fun chop (0: int) xs = ([], xs)
| chop _ [] = ([], [])
| chop n (x :: xs) = chop (n - 1) xs |>> cons x;
(*take the first n elements from a list*)
fun take (n: int, []) = []
| take (n, x :: xs) =
if n > 0 then x :: take (n - 1, xs) else [];
(*drop the first n elements from a list*)
fun drop (n: int, []) = []
| drop (n, x :: xs) =
if n > 0 then drop (n - 1, xs) else x :: xs;
fun dropwhile P [] = []
| dropwhile P (ys as x::xs) = if P x then dropwhile P xs else ys;
(*return nth element of a list, where 0 designates the first element;
raise Subscript if list too short*)
fun nth xs i = List.nth (xs, i);
fun nth_list xss i = nth xss i handle Subscript => [];
fun nth_map 0 f (x :: xs) = f x :: xs
| nth_map n f (x :: xs) = x :: nth_map (n - 1) f xs
| nth_map (_: int) _ [] = raise Subscript;
fun nth_drop n xs =
List.take (xs, n) @ List.drop (xs, n + 1);
fun map_index f =
let
fun mapp (_: int) [] = []
| mapp i (x :: xs) = f (i, x) :: mapp (i + 1) xs
in mapp 0 end;
fun fold_index f =
let
fun fold_aux (_: int) [] y = y
| fold_aux i (x :: xs) y = fold_aux (i + 1) xs (f (i, x) y);
in fold_aux 0 end;
val last_elem = List.last;
(*rear decomposition*)
fun split_last [] = raise Empty
| split_last [x] = ([], x)
| split_last (x :: xs) = apfst (cons x) (split_last xs);
(*find position of first element satisfying a predicate*)
fun find_index pred =
let fun find (_: int) [] = ~1
| find n (x :: xs) = if pred x then n else find (n + 1) xs;
in find 0 end;
fun find_index_eq x = find_index (equal x);
(*find first element satisfying predicate*)
val find_first = List.find;
(*get first element by lookup function*)
fun get_first _ [] = NONE
| get_first f (x :: xs) =
(case f x of
NONE => get_first f xs
| some => some);
fun get_index f =
let
fun get (_: int) [] = NONE
| get i (x :: xs) =
case f x
of NONE => get (i + 1) xs
| SOME y => SOME (i, y)
in get 0 end;
val flat = List.concat;
fun unflat (xs :: xss) ys =
let val (ps, qs) = chop (length xs) ys
in ps :: unflat xss qs end
| unflat [] [] = []
| unflat _ _ = raise UnequalLengths;
fun burrow f xss = unflat xss (f (flat xss));
fun burrow_options f os = map (try hd) (burrow f (map the_list os));
fun fold_burrow f xss s =
apfst (unflat xss) (f (flat xss) s);
(*separate s [x1, x2, ..., xn] ===> [x1, s, x2, s, ..., s, xn]*)
fun separate s (x :: (xs as _ :: _)) = x :: s :: separate s xs
| separate _ xs = xs;
fun surround s (x :: xs) = s :: x :: surround s xs
| surround s [] = [s];
(*make the list [x, x, ..., x] of length n*)
fun replicate (n: int) x =
let fun rep (0, xs) = xs
| rep (n, xs) = rep (n - 1, x :: xs)
in
if n < 0 then raise Subscript
else rep (n, [])
end;
fun translate_string f = String.translate (f o String.str);
(*multiply [a, b, c, ...] * [xs, ys, zs, ...]*)
fun multiply [] _ = []
| multiply (x :: xs) yss = map (cons x) yss @ multiply xs yss;
(* direct product *)
fun map_product f _ [] = []
| map_product f [] _ = []
| map_product f (x :: xs) ys = map (f x) ys @ map_product f xs ys;
fun fold_product f _ [] z = z
| fold_product f [] _ z = z
| fold_product f (x :: xs) ys z = z |> fold (f x) ys |> fold_product f xs ys;
(* lists of pairs *)
exception UnequalLengths;
fun map2 _ [] [] = []
| map2 f (x :: xs) (y :: ys) = f x y :: map2 f xs ys
| map2 _ _ _ = raise UnequalLengths;
fun fold2 f [] [] z = z
| fold2 f (x :: xs) (y :: ys) z = fold2 f xs ys (f x y z)
| fold2 f _ _ _ = raise UnequalLengths;
fun map_split f [] = ([], [])
| map_split f (x :: xs) =
let
val (y, w) = f x;
val (ys, ws) = map_split f xs;
in (y :: ys, w :: ws) end;
fun zip_options (x :: xs) (SOME y :: ys) = (x, y) :: zip_options xs ys
| zip_options (_ :: xs) (NONE :: ys) = zip_options xs ys
| zip_options _ [] = []
| zip_options [] _ = raise UnequalLengths;
(*combine two lists forming a list of pairs:
[x1, ..., xn] ~~ [y1, ..., yn] ===> [(x1, y1), ..., (xn, yn)]*)
fun [] ~~ [] = []
| (x :: xs) ~~ (y :: ys) = (x, y) :: (xs ~~ ys)
| _ ~~ _ = raise UnequalLengths;
(*inverse of ~~; the old 'split':
[(x1, y1), ..., (xn, yn)] ===> ([x1, ..., xn], [y1, ..., yn])*)
val split_list = ListPair.unzip;
fun burrow_fst f xs = split_list xs |>> f |> op ~~;
(* prefixes, suffixes *)
fun is_prefix _ [] _ = true
| is_prefix eq (x :: xs) (y :: ys) = eq (x, y) andalso is_prefix eq xs ys
| is_prefix eq _ _ = false;
(* [x1, ..., xi, ..., xn] ---> ([x1, ..., x(i-1)], [xi, ..., xn])
where xi is the first element that does not satisfy the predicate*)
fun take_prefix (pred : 'a -> bool) (xs: 'a list) : 'a list * 'a list =
let fun take (rxs, []) = (rev rxs, [])
| take (rxs, x :: xs) =
if pred x then take(x :: rxs, xs) else (rev rxs, x :: xs)
in take([], xs) end;
fun chop_prefix eq ([], ys) = ([], ([], ys))
| chop_prefix eq (xs, []) = ([], (xs, []))
| chop_prefix eq (xs as x :: xs', ys as y :: ys') =
if eq (x, y) then
let val (ps', xys'') = chop_prefix eq (xs', ys')
in (x :: ps', xys'') end
else ([], (xs, ys));
(* [x1, ..., xi, ..., xn] ---> ([x1, ..., xi], [x(i+1), ..., xn])
where xi is the last element that does not satisfy the predicate*)
fun take_suffix _ [] = ([], [])
| take_suffix pred (x :: xs) =
(case take_suffix pred xs of
([], sffx) => if pred x then ([], x :: sffx) else ([x], sffx)
| (prfx, sffx) => (x :: prfx, sffx));
fun prefixes1 [] = []
| prefixes1 (x :: xs) = map (cons x) ([] :: prefixes1 xs);
fun prefixes xs = [] :: prefixes1 xs;
fun suffixes1 xs = map rev (prefixes1 (rev xs));
fun suffixes xs = [] :: suffixes1 xs;
(** integers **)
fun inc i = (i := ! i + (1: int); ! i);
fun dec i = (i := ! i - (1: int); ! i);
(* lists of integers *)
(*make the list [from, from + 1, ..., to]*)
fun ((i: int) upto j) =
if i > j then [] else i :: (i + 1 upto j);
(*make the list [from, from - 1, ..., to]*)
fun ((i: int) downto j) =
if i < j then [] else i :: (i - 1 downto j);
(* convert integers to strings *)
(*expand the number in the given base;
example: radixpand (2, 8) gives [1, 0, 0, 0]*)
fun radixpand (base, num) : int list =
let
fun radix (n, tail) =
if n < base then n :: tail
else radix (n div base, (n mod base) :: tail)
in radix (num, []) end;
(*expands a number into a string of characters starting from "zerochar";
example: radixstring (2, "0", 8) gives "1000"*)
fun radixstring (base, zerochar, num) =
let val offset = ord zerochar;
fun chrof n = chr (offset + n)
in implode (map chrof (radixpand (base, num))) end;
val string_of_int = Int.toString;
fun signed_string_of_int i =
if i < 0 then "-" ^ string_of_int (~ i) else string_of_int i;
fun string_of_indexname (a, 0) = a
| string_of_indexname (a, i) = a ^ "_" ^ string_of_int i;
(* read integers *)
fun read_radix_int radix cs =
let
val zero = ord "0";
val limit = zero + radix;
fun scan (num, []) = (num, [])
| scan (num, c :: cs) =
if zero <= ord c andalso ord c < limit then
scan (radix * num + (ord c - zero), cs)
else (num, c :: cs);
in scan (0, cs) end;
val read_int = read_radix_int 10;
fun oct_char s = chr (#1 (read_radix_int 8 (explode s)));
(** strings **)
(* functions tuned for strings, avoiding explode *)
fun nth_string str i =
(case try String.substring (str, i, 1) of
SOME s => s
| NONE => raise Subscript);
fun fold_string f str x0 =
let
val n = size str;
fun iter (x, i) =
if i < n then iter (f (String.substring (str, i, 1)) x, i + 1) else x;
in iter (x0, 0) end;
fun exists_string pred str =
let
val n = size str;
fun ex i = i < n andalso (pred (String.substring (str, i, 1)) orelse ex (i + 1));
in ex 0 end;
fun forall_string pred = not o exists_string (not o pred);
fun first_field sep str =
let
val n = size sep;
val len = size str;
fun find i =
if i + n > len then NONE
else if String.substring (str, i, n) = sep then SOME i
else find (i + 1);
in
(case find 0 of
NONE => NONE
| SOME i => SOME (String.substring (str, 0, i), String.extract (str, i + n, NONE)))
end;
(*enclose in brackets*)
fun enclose lpar rpar str = lpar ^ str ^ rpar;
fun unenclose str = String.substring (str, 1, size str - 2);
(*simple quoting (does not escape special chars)*)
val quote = enclose "\"" "\"";
(*space_implode "..." (explode "hello") = "h...e...l...l...o"*)
fun space_implode a bs = implode (separate a bs);
val commas = space_implode ", ";
val commas_quote = commas o map quote;
(*concatenate messages, one per line, into a string*)
val cat_lines = space_implode "\n";
(*space_explode "." "h.e..l.lo" = ["h", "e", "", "l", "lo"]*)
fun space_explode _ "" = []
| space_explode sep s = String.fields (fn c => str c = sep) s;
val split_lines = space_explode "\n";
fun prefix_lines "" txt = txt
| prefix_lines prfx txt = txt |> split_lines |> map (fn s => prfx ^ s) |> cat_lines;
fun prefix prfx s = prfx ^ s;
fun suffix sffx s = s ^ sffx;
fun unprefix prfx s =
if String.isPrefix prfx s then String.substring (s, size prfx, size s - size prfx)
else raise Fail "unprefix";
fun unsuffix sffx s =
if String.isSuffix sffx s then String.substring (s, 0, size s - size sffx)
else raise Fail "unsuffix";
fun replicate_string (0: int) _ = ""
| replicate_string 1 a = a
| replicate_string k a =
if k mod 2 = 0 then replicate_string (k div 2) (a ^ a)
else replicate_string (k div 2) (a ^ a) ^ a;
(*crude matching of str against simple glob pat*)
fun match_string pat str =
let
fun match [] _ = true
| match (p :: ps) s =
size p <= size s andalso
(case try (unprefix p) s of
SOME s' => match ps s'
| NONE => match (p :: ps) (String.substring (s, 1, size s - 1)));
in match (space_explode "*" pat) str end;
(** lists as sets -- see also Pure/General/ord_list.ML **)
(* canonical operations *)
fun member eq list x =
let
fun memb [] = false
| memb (y :: ys) = eq (x, y) orelse memb ys;
in memb list end;
fun insert eq x xs = if member eq xs x then xs else x :: xs;
fun remove eq x xs = if member eq xs x then filter_out (fn y => eq (x, y)) xs else xs;
fun update eq x xs = cons x (remove eq x xs);
fun subtract eq = fold (remove eq);
fun merge _ ([], ys) = ys
| merge eq (xs, ys) = fold_rev (insert eq) ys xs;
(* old-style infixes *)
fun x mem xs = member (op =) xs x;
fun (x: int) mem_int xs = member (op =) xs x;
fun (x: string) mem_string xs = member (op =) xs x;
(*union of sets represented as lists: no repetitions*)
fun xs union [] = xs
| [] union ys = ys
| (x :: xs) union ys = xs union (insert (op =) x ys);
(*union of sets, optimized version for ints*)
fun (xs:int list) union_int [] = xs
| [] union_int ys = ys
| (x :: xs) union_int ys = xs union_int (insert (op =) x ys);
(*union of sets, optimized version for strings*)
fun (xs:string list) union_string [] = xs
| [] union_string ys = ys
| (x :: xs) union_string ys = xs union_string (insert (op =) x ys);
(*generalized union*)
fun gen_union eq (xs, []) = xs
| gen_union eq ([], ys) = ys
| gen_union eq (x :: xs, ys) = gen_union eq (xs, insert eq x ys);
(*intersection*)
fun [] inter ys = []
| (x :: xs) inter ys =
if x mem ys then x :: (xs inter ys) else xs inter ys;
(*intersection, optimized version for ints*)
fun ([]:int list) inter_int ys = []
| (x :: xs) inter_int ys =
if x mem_int ys then x :: (xs inter_int ys) else xs inter_int ys;
(*intersection, optimized version for strings *)
fun ([]:string list) inter_string ys = []
| (x :: xs) inter_string ys =
if x mem_string ys then x :: (xs inter_string ys) else xs inter_string ys;
(*generalized intersection*)
fun gen_inter eq ([], ys) = []
| gen_inter eq (x::xs, ys) =
if member eq ys x then x :: gen_inter eq (xs, ys)
else gen_inter eq (xs, ys);
(*subset*)
fun [] subset ys = true
| (x :: xs) subset ys = x mem ys andalso xs subset ys;
(*subset, optimized version for ints*)
fun ([]: int list) subset_int ys = true
| (x :: xs) subset_int ys = x mem_int ys andalso xs subset_int ys;
(*subset, optimized version for strings*)
fun ([]: string list) subset_string ys = true
| (x :: xs) subset_string ys = x mem_string ys andalso xs subset_string ys;
(*set equality*)
fun eq_set (xs, ys) =
xs = ys orelse (xs subset ys andalso ys subset xs);
(*set equality for strings*)
fun eq_set_string ((xs: string list), ys) =
xs = ys orelse (xs subset_string ys andalso ys subset_string xs);
fun gen_subset eq (xs, ys) = forall (member eq ys) xs;
fun gen_eq_set eq (xs, ys) =
eq_list eq (xs, ys) orelse
(gen_subset eq (xs, ys) andalso gen_subset (eq o swap) (ys, xs));
(*removing an element from a list WITHOUT duplicates*)
fun (y :: ys) \ x = if x = y then ys else y :: (ys \ x)
| [] \ x = [];
fun ys \\ xs = foldl (op \) (ys,xs);
(*makes a list of the distinct members of the input; preserves order, takes
first of equal elements*)
fun distinct eq lst =
let
fun dist (rev_seen, []) = rev rev_seen
| dist (rev_seen, x :: xs) =
if member eq rev_seen x then dist (rev_seen, xs)
else dist (x :: rev_seen, xs);
in dist ([], lst) end;
(*returns a list containing all repeated elements exactly once; preserves
order, takes first of equal elements*)
fun duplicates eq lst =
let
fun dups (rev_dups, []) = rev rev_dups
| dups (rev_dups, x :: xs) =
if member eq rev_dups x orelse not (member eq xs x) then
dups (rev_dups, xs)
else dups (x :: rev_dups, xs);
in dups ([], lst) end;
fun has_duplicates eq =
let
fun dups [] = false
| dups (x :: xs) = member eq xs x orelse dups xs;
in dups end;
(** lists as multisets **)
fun remove1 _ _ [] = raise Empty
| remove1 eq y (x::xs) = if eq (y, x) then xs else x :: remove1 eq y xs;
fun submultiset _ ([], _) = true
| submultiset eq (x :: xs, ys) = member eq ys x andalso submultiset eq (xs, remove1 eq x ys);
(** orders **)
fun is_equal EQUAL = true
| is_equal _ = false;
fun rev_order LESS = GREATER
| rev_order EQUAL = EQUAL
| rev_order GREATER = LESS;
(*assume rel is a linear strict order*)
fun make_ord rel (x, y) =
if rel (x, y) then LESS
else if rel (y, x) then GREATER
else EQUAL;
fun bool_ord (false, true) = LESS
| bool_ord (true, false) = GREATER
| bool_ord _ = EQUAL;
val int_ord = Int.compare;
val string_ord = String.compare;
fun fast_string_ord (s1, s2) =
(case int_ord (size s1, size s2) of EQUAL => string_ord (s1, s2) | ord => ord);
fun option_ord ord (SOME x, SOME y) = ord (x, y)
| option_ord _ (NONE, NONE) = EQUAL
| option_ord _ (NONE, SOME _) = LESS
| option_ord _ (SOME _, NONE) = GREATER;
(*lexicographic product*)
fun prod_ord a_ord b_ord ((x, y), (x', y')) =
(case a_ord (x, x') of EQUAL => b_ord (y, y') | ord => ord);
(*dictionary order -- in general NOT well-founded!*)
fun dict_ord elem_ord (x :: xs, y :: ys) =
(case elem_ord (x, y) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord)
| dict_ord _ ([], []) = EQUAL
| dict_ord _ ([], _ :: _) = LESS
| dict_ord _ (_ :: _, []) = GREATER;
(*lexicographic product of lists*)
fun list_ord elem_ord (xs, ys) =
(case int_ord (length xs, length ys) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord);
(* sorting *)
(*quicksort -- stable, i.e. does not reorder equal elements*)
fun quicksort unique ord =
let
fun qsort [] = []
| qsort (xs as [_]) = xs
| qsort (xs as [x, y]) =
(case ord (x, y) of
LESS => xs
| EQUAL => if unique then [x] else xs
| GREATER => [y, x])
| qsort xs =
let val (lts, eqs, gts) = part (nth xs (length xs div 2)) xs
in qsort lts @ eqs @ qsort gts end
and part _ [] = ([], [], [])
| part pivot (x :: xs) = add (ord (x, pivot)) x (part pivot xs)
and add LESS x (lts, eqs, gts) = (x :: lts, eqs, gts)
| add EQUAL x (lts, [], gts) = (lts, [x], gts)
| add EQUAL x (res as (lts, eqs, gts)) = if unique then res else (lts, x :: eqs, gts)
| add GREATER x (lts, eqs, gts) = (lts, eqs, x :: gts);
in qsort end;
fun sort ord = quicksort false ord;
fun sort_distinct ord = quicksort true ord;
val sort_strings = sort string_ord;
fun sort_wrt sel xs = sort (string_ord o pairself sel) xs;
(** random numbers **)
exception RANDOM;
fun rmod x y = x - y * Real.realFloor (x / y);
local
val a = 16807.0;
val m = 2147483647.0;
val random_seed = ref 1.0;
in
fun random () = CRITICAL (fn () =>
let val r = rmod (a * ! random_seed) m
in (random_seed := r; r) end);
end;
fun random_range l h =
if h < l orelse l < 0 then raise RANDOM
else l + Real.floor (rmod (random ()) (real (h - l + 1)));
fun one_of xs = nth xs (random_range 0 (length xs - 1));
fun frequency xs =
let
val sum = foldl op + (0, map fst xs);
fun pick n ((k: int, x) :: xs) =
if n <= k then x else pick (n - k) xs
in pick (random_range 1 sum) xs end;
(** misc **)
fun divide_and_conquer decomp x =
let val (ys, recomb) = decomp x
in recomb (map (divide_and_conquer decomp) ys) end;
(*Partition a list into buckets [ bi, b(i+1), ..., bj ]
putting x in bk if p(k)(x) holds. Preserve order of elements if possible.*)
fun partition_list p i j =
let fun part k xs =
if k>j then
(case xs of [] => []
| _ => raise Fail "partition_list")
else
let val (ns, rest) = List.partition (p k) xs;
in ns :: part(k+1)rest end
in part (i: int) end;
fun partition_eq (eq:'a * 'a -> bool) =
let
fun part [] = []
| part (x :: ys) =
let val (xs, xs') = List.partition (fn y => eq (x, y)) ys
in (x::xs)::(part xs') end
in part end;
(* generating identifiers *)
(** Freshly generated identifiers; supplied prefix MUST start with a letter **)
local
(*Maps 0-61 to A-Z, a-z, 0-9; exclude _ or ' to avoid clash with internal/unusual indentifiers*)
fun gensym_char i =
if i<26 then chr (ord "A" + i)
else if i<52 then chr (ord "a" + i - 26)
else chr (ord "0" + i - 52);
val char_vec = Vector.tabulate (62, gensym_char);
fun newid n = implode (map (fn i => Vector.sub (char_vec, i)) (radixpand (62, n)));
val gensym_seed = ref (0: int);
in
fun gensym pre = pre ^ newid (NAMED_CRITICAL "gensym" (fn () => inc gensym_seed));
end;
(* stamps and serial numbers *)
type stamp = unit ref;
val stamp: unit -> stamp = ref;
type serial = int;
val serial = Multithreading.serial;
val serial_string = string_of_int o serial;
(* generic objects *)
(*note that the builtin exception datatype may be extended by new
constructors at any time*)
structure Object = struct type T = exn end;
end;
structure BasicLibrary: BASIC_LIBRARY = Library;
open BasicLibrary;