1 (* Title: Pure/library.ML
3 Author: Lawrence C Paulson, Cambridge University Computer Laboratory
4 Author: Markus Wenzel, TU Muenchen
6 Basic library: functions, options, pairs, booleans, lists, integers,
7 strings, lists as sets, orders, current directory, misc.
9 See also General/basics.ML for the most fundamental concepts.
15 infix 4 ~~ upto downto
16 infix orf andf \ \\ mem mem_int mem_string union union_int
17 union_string inter inter_int inter_string subset subset_int subset_string
19 signature BASIC_LIBRARY =
22 val undefined: 'a -> 'b
25 val flip: ('a -> 'b -> 'c) -> 'b -> 'a -> 'c
26 val curry: ('a * 'b -> 'c) -> 'a -> 'b -> 'c
27 val uncurry: ('a -> 'b -> 'c) -> 'a * 'b -> 'c
28 val |>>> : ('a * 'c) * ('a -> 'b * 'd) -> 'b * ('c * 'd)
29 val ? : bool * ('a -> 'a) -> 'a -> 'a
30 val oo: ('a -> 'b) * ('c -> 'd -> 'a) -> 'c -> 'd -> 'b
31 val ooo: ('a -> 'b) * ('c -> 'd -> 'e -> 'a) -> 'c -> 'd -> 'e -> 'b
32 val oooo: ('a -> 'b) * ('c -> 'd -> 'e -> 'f -> 'a) -> 'c -> 'd -> 'e -> 'f -> 'b
33 val funpow: int -> ('a -> 'a) -> 'a -> 'a
36 exception SYS_ERROR of string
37 val sys_error: string -> 'a
38 exception ERROR of string
39 val error: string -> 'a
40 val cat_error: string -> string -> 'a
41 val assert_all: ('a -> bool) -> 'a list -> ('a -> string) -> unit
44 val pair: 'a -> 'b -> 'a * 'b
45 val rpair: 'a -> 'b -> 'b * 'a
46 val fst: 'a * 'b -> 'a
47 val snd: 'a * 'b -> 'b
48 val eq_fst: ('a * 'c -> bool) -> ('a * 'b) * ('c * 'd) -> bool
49 val eq_snd: ('b * 'd -> bool) -> ('a * 'b) * ('c * 'd) -> bool
50 val eq_pair: ('a * 'c -> bool) -> ('b * 'd -> bool) -> ('a * 'b) * ('c * 'd) -> bool
51 val swap: 'a * 'b -> 'b * 'a
52 val apfst: ('a -> 'b) -> 'a * 'c -> 'b * 'c
53 val apsnd: ('a -> 'b) -> 'c * 'a -> 'c * 'b
54 val pairself: ('a -> 'b) -> 'a * 'a -> 'b * 'b
57 val equal: ''a -> ''a -> bool
58 val not_equal: ''a -> ''a -> bool
59 val orf: ('a -> bool) * ('a -> bool) -> 'a -> bool
60 val andf: ('a -> bool) * ('a -> bool) -> 'a -> bool
61 val exists: ('a -> bool) -> 'a list -> bool
62 val forall: ('a -> bool) -> 'a list -> bool
63 val set: bool ref -> bool
64 val reset: bool ref -> bool
65 val toggle: bool ref -> bool
66 val change: 'a ref -> ('a -> 'a) -> unit
67 val setmp_noncritical: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
68 val setmp: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
71 exception UnequalLengths
72 val single: 'a -> 'a list
73 val the_single: 'a list -> 'a
74 val singleton: ('a list -> 'b list) -> 'a -> 'b
75 val apply: ('a -> 'a) list -> 'a -> 'a
76 val foldr1: ('a * 'a -> 'a) -> 'a list -> 'a
77 val foldl_map: ('a * 'b -> 'a * 'c) -> 'a * 'b list -> 'a * 'c list
78 val flat: 'a list list -> 'a list
79 val unflat: 'a list list -> 'b list -> 'b list list
80 val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
81 val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
82 val maps: ('a -> 'b list) -> 'a list -> 'b list
83 val chop: int -> 'a list -> 'a list * 'a list
84 val dropwhile: ('a -> bool) -> 'a list -> 'a list
85 val nth: 'a list -> int -> 'a
86 val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
87 val nth_list: 'a list list -> int -> 'a list
88 val map_index: (int * 'a -> 'b) -> 'a list -> 'b list
89 val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
90 val split_last: 'a list -> 'a list * 'a
91 val find_index: ('a -> bool) -> 'a list -> int
92 val find_index_eq: ''a -> ''a list -> int
93 val find_first: ('a -> bool) -> 'a list -> 'a option
94 val get_index: ('a -> 'b option) -> 'a list -> (int * 'b) option
95 val get_first: ('a -> 'b option) -> 'a list -> 'b option
96 val eq_list: ('a * 'b -> bool) -> 'a list * 'b list -> bool
97 val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
98 val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
99 val zip_options: 'a list -> 'b option list -> ('a * 'b) list
100 val ~~ : 'a list * 'b list -> ('a * 'b) list
101 val split_list: ('a * 'b) list -> 'a list * 'b list
102 val separate: 'a -> 'a list -> 'a list
103 val replicate: int -> 'a -> 'a list
104 val multiply: 'a list -> 'a list list -> 'a list list
105 val product: 'a list -> 'b list -> ('a * 'b) list
106 val filter: ('a -> bool) -> 'a list -> 'a list
107 val filter_out: ('a -> bool) -> 'a list -> 'a list
108 val map_filter: ('a -> 'b option) -> 'a list -> 'b list
109 val is_prefix: ('a * 'a -> bool) -> 'a list -> 'a list -> bool
110 val take_prefix: ('a -> bool) -> 'a list -> 'a list * 'a list
111 val chop_prefix: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list * ('a list * 'b list)
112 val take_suffix: ('a -> bool) -> 'a list -> 'a list * 'a list
113 val prefixes1: 'a list -> 'a list list
114 val prefixes: 'a list -> 'a list list
115 val suffixes1: 'a list -> 'a list list
116 val suffixes: 'a list -> 'a list list
119 val inc: int ref -> int
120 val dec: int ref -> int
121 val upto: int * int -> int list
122 val downto: int * int -> int list
123 val radixpand: int * int -> int list
124 val radixstring: int * string * int -> string
125 val string_of_int: int -> string
126 val signed_string_of_int: int -> string
127 val string_of_indexname: string * int -> string
128 val read_intinf: int -> string list -> IntInf.int * string list
129 val read_int: string list -> int * string list
130 val oct_char: string -> string
133 val nth_string: string -> int -> string
134 val fold_string: (string -> 'a -> 'a) -> string -> 'a -> 'a
135 val exists_string: (string -> bool) -> string -> bool
136 val forall_string: (string -> bool) -> string -> bool
137 val enclose: string -> string -> string -> string
138 val unenclose: string -> string
139 val quote: string -> string
140 val space_implode: string -> string list -> string
141 val commas: string list -> string
142 val commas_quote: string list -> string
143 val cat_lines: string list -> string
144 val space_explode: string -> string -> string list
145 val split_lines: string -> string list
146 val prefix_lines: string -> string -> string
147 val untabify: string list -> string list
148 val prefix: string -> string -> string
149 val suffix: string -> string -> string
150 val unprefix: string -> string -> string
151 val unsuffix: string -> string -> string
152 val replicate_string: int -> string -> string
153 val translate_string: (string -> string) -> string -> string
155 (*lists as sets -- see also Pure/General/ord_list.ML*)
156 val member: ('b * 'a -> bool) -> 'a list -> 'b -> bool
157 val insert: ('a * 'a -> bool) -> 'a -> 'a list -> 'a list
158 val remove: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
159 val update: ('a * 'a -> bool) -> 'a -> 'a list -> 'a list
160 val subtract: ('b * 'a -> bool) -> 'b list -> 'a list -> 'a list
161 val merge: ('a * 'a -> bool) -> 'a list * 'a list -> 'a list
162 val mem: ''a * ''a list -> bool
163 val mem_int: int * int list -> bool
164 val mem_string: string * string list -> bool
165 val union: ''a list * ''a list -> ''a list
166 val union_int: int list * int list -> int list
167 val union_string: string list * string list -> string list
168 val gen_union: ('a * 'a -> bool) -> 'a list * 'a list -> 'a list
169 val gen_inter: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list
170 val inter: ''a list * ''a list -> ''a list
171 val inter_int: int list * int list -> int list
172 val inter_string: string list * string list -> string list
173 val subset: ''a list * ''a list -> bool
174 val subset_int: int list * int list -> bool
175 val subset_string: string list * string list -> bool
176 val eq_set: ''a list * ''a list -> bool
177 val eq_set_string: string list * string list -> bool
178 val gen_subset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
179 val gen_eq_set: ('a * 'b -> bool) -> 'a list * 'b list -> bool
180 val \ : ''a list * ''a -> ''a list
181 val \\ : ''a list * ''a list -> ''a list
182 val distinct: ('a * 'a -> bool) -> 'a list -> 'a list
183 val duplicates: ('a * 'a -> bool) -> 'a list -> 'a list
184 val has_duplicates: ('a * 'a -> bool) -> 'a list -> bool
186 (*lists as multisets*)
187 val remove1: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
188 val submultiset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
191 val is_equal: order -> bool
192 val rev_order: order -> order
193 val make_ord: ('a * 'a -> bool) -> 'a * 'a -> order
194 val int_ord: int * int -> order
195 val string_ord: string * string -> order
196 val fast_string_ord: string * string -> order
197 val option_ord: ('a * 'b -> order) -> 'a option * 'b option -> order
198 val prod_ord: ('a * 'b -> order) -> ('c * 'd -> order) -> ('a * 'c) * ('b * 'd) -> order
199 val dict_ord: ('a * 'b -> order) -> 'a list * 'b list -> order
200 val list_ord: ('a * 'b -> order) -> 'a list * 'b list -> order
201 val sort: ('a * 'a -> order) -> 'a list -> 'a list
202 val sort_distinct: ('a * 'a -> order) -> 'a list -> 'a list
203 val sort_strings: string list -> string list
204 val sort_wrt: ('a -> string) -> 'a list -> 'a list
208 val random: unit -> real
209 val random_range: int -> int -> int
210 val one_of: 'a list -> 'a
211 val frequency: (int * 'a) list -> 'a
214 val divide_and_conquer: ('a -> 'a list * ('b list -> 'b)) -> 'a -> 'b
215 val partition_eq: ('a * 'a -> bool) -> 'a list -> 'a list list
216 val partition_list: (int -> 'a -> bool) -> int -> int -> 'a list -> 'a list list
217 val gensym: string -> string
219 val stamp: unit -> stamp
221 val serial: unit -> serial
222 val serial_string: unit -> string
223 structure Object: sig type T end
228 include BASIC_LIBRARY
229 val foldl: ('a * 'b -> 'a) -> 'a * 'b list -> 'a
230 val foldr: ('a * 'b -> 'b) -> 'a list * 'b -> 'b
231 val take: int * 'a list -> 'a list
232 val drop: int * 'a list -> 'a list
233 val last_elem: 'a list -> 'a
236 structure Library: LIBRARY =
241 fun undefined _ = raise Match;
245 fun flip f x y = f y x;
246 fun curry f x y = f (x, y);
247 fun uncurry f (x, y) = f x y;
249 (*application and structured results -- old version*)
250 fun (x, y) |>>> f = let val (x', z) = f x in (x', (y, z)) end;
252 (*conditional application*)
253 fun b ? f = fn x => if b then f x else x;
255 (*composition with multiple args*)
256 fun (f oo g) x y = f (g x y);
257 fun (f ooo g) x y z = f (g x y z);
258 fun (f oooo g) x y z w = f (g x y z w);
260 (*function exponentiation: f(...(f x)...) with n applications of f*)
262 | funpow n f x = funpow (n - 1) f (f x);
267 exception SYS_ERROR of string;
268 fun sys_error msg = raise SYS_ERROR msg;
270 exception ERROR of string;
271 fun error msg = raise ERROR msg;
273 fun cat_error "" msg = error msg
274 | cat_error msg1 msg2 = error (msg1 ^ "\n" ^ msg2);
276 fun assert_all pred list msg =
279 | ass (x :: xs) = if pred x then ass xs else error (msg x);
285 fun pair x y = (x, y);
286 fun rpair x y = (y, x);
291 fun eq_fst eq ((x1, _), (x2, _)) = eq (x1, x2);
292 fun eq_snd eq ((_, y1), (_, y2)) = eq (y1, y2);
293 fun eq_pair eqx eqy ((x1, y1), (x2, y2)) = eqx (x1, x2) andalso eqy (y1, y2);
295 fun swap (x, y) = (y, x);
297 fun apfst f (x, y) = (f x, y);
298 fun apsnd f (x, y) = (x, f y);
299 fun pairself f (x, y) = (f x, f y);
304 (*polymorphic equality*)
305 fun equal x y = x = y;
306 fun not_equal x y = x <> y;
308 (*combining predicates*)
309 fun p orf q = fn x => p x orelse q x;
310 fun p andf q = fn x => p x andalso q x;
312 (*exists pred [x1, ..., xn] ===> pred x1 orelse ... orelse pred xn*)
313 fun exists (pred: 'a -> bool) : 'a list -> bool =
314 let fun boolf [] = false
315 | boolf (x :: xs) = pred x orelse boolf xs
318 (*forall pred [x1, ..., xn] ===> pred x1 andalso ... andalso pred xn*)
319 fun forall (pred: 'a -> bool) : 'a list -> bool =
320 let fun boolf [] = true
321 | boolf (x :: xs) = pred x andalso boolf xs
327 fun set flag = (flag := true; true);
328 fun reset flag = (flag := false; false);
329 fun toggle flag = (flag := not (! flag); ! flag);
331 fun change r f = r := f (! r);
333 (*temporarily set flag during execution*)
334 fun setmp_noncritical flag value f x =
336 val orig_value = ! flag;
337 val _ = flag := value;
338 val result = Exn.capture f x;
339 val _ = flag := orig_value;
340 in Exn.release result end;
342 fun setmp flag value f x = NAMED_CRITICAL "setmp" (fn () => setmp_noncritical flag value f x);
348 exception UnequalLengths;
352 fun the_single [x] = x
353 | the_single _ = raise Empty;
355 fun singleton f x = the_single (f [x]);
358 | apply (f :: fs) x = apply fs (f x);
361 (* fold -- old versions *)
363 (*the following versions of fold are designed to fit nicely with infixes*)
365 (* (op @) (e, [x1, ..., xn]) ===> ((e @ x1) @ x2) ... @ xn
366 for operators that associate to the left (TAIL RECURSIVE)*)
367 fun foldl (f: 'a * 'b -> 'a) : 'a * 'b list -> 'a =
368 let fun itl (e, []) = e
369 | itl (e, a::l) = itl (f(e, a), l)
372 (* (op @) ([x1, ..., xn], e) ===> x1 @ (x2 ... @ (xn @ e))
373 for operators that associate to the right (not tail recursive)*)
376 | itr (a::l) = f(a, itr l)
379 (* (op @) [x1, ..., xn] ===> x1 @ (x2 ... @ (x[n-1] @ xn))
380 for n > 0, operators that associate to the right (not tail recursive)*)
381 fun foldr1 f [] = raise Empty
384 | itr (x::l) = f(x, itr l)
389 fun fold_aux (x, []) = (x, [])
390 | fold_aux (x, y :: ys) =
392 val (x', y') = f (x, y);
393 val (x'', ys') = fold_aux (x', ys);
394 in (x'', y' :: ys') end;
398 (* basic list functions *)
400 fun eq_list eq (list1, list2) =
402 fun eq_lst (x :: xs, y :: ys) = eq (x, y) andalso eq_lst (xs, ys)
404 in length list1 = length list2 andalso eq_lst (list1, list2) end;
407 | maps f (x :: xs) = f x @ maps f xs;
409 fun chop 0 xs = ([], xs)
410 | chop _ [] = ([], [])
411 | chop n (x :: xs) = chop (n - 1) xs |>> cons x;
413 (*take the first n elements from a list*)
414 fun take (n, []) = []
415 | take (n, x :: xs) =
416 if n > 0 then x :: take (n - 1, xs) else [];
418 (*drop the first n elements from a list*)
419 fun drop (n, []) = []
420 | drop (n, x :: xs) =
421 if n > 0 then drop (n - 1, xs) else x :: xs;
423 fun dropwhile P [] = []
424 | dropwhile P (ys as x::xs) = if P x then dropwhile P xs else ys;
426 (*return nth element of a list, where 0 designates the first element;
427 raise Subscript if list too short*)
428 fun nth xs i = List.nth (xs, i);
430 fun nth_list xss i = nth xss i handle Subscript => [];
432 fun nth_map 0 f (x :: xs) = f x :: xs
433 | nth_map n f (x :: xs) = x :: nth_map (n - 1) f xs
434 | nth_map _ _ [] = raise Subscript;
439 | mapp i (x :: xs) = f (i, x) :: mapp (i+1) xs
444 fun fold_aux _ [] y = y
445 | fold_aux i (x :: xs) y = fold_aux (i+1) xs (f (i, x) y);
448 val last_elem = List.last;
450 (*rear decomposition*)
451 fun split_last [] = raise Empty
452 | split_last [x] = ([], x)
453 | split_last (x :: xs) = apfst (cons x) (split_last xs);
455 (*find the position of an element in a list*)
456 fun find_index pred =
457 let fun find _ [] = ~1
458 | find n (x :: xs) = if pred x then n else find (n + 1) xs;
461 fun find_index_eq x = find_index (equal x);
463 (*find first element satisfying predicate*)
464 val find_first = List.find;
466 (*get first element by lookup function*)
467 fun get_first _ [] = NONE
468 | get_first f (x :: xs) =
470 NONE => get_first f xs
478 of NONE => get (i + 1) xs
479 | SOME y => SOME (i, y)
482 val flat = List.concat;
484 fun unflat (xs :: xss) ys =
485 let val (ps, qs) = chop (length xs) ys
486 in ps :: unflat xss qs end
488 | unflat _ _ = raise UnequalLengths;
490 fun burrow f xss = unflat xss (f (flat xss));
492 fun fold_burrow f xss s =
493 apfst (unflat xss) (f (flat xss) s);
495 (*separate s [x1, x2, ..., xn] ===> [x1, s, x2, s, ..., s, xn]*)
496 fun separate s (x :: (xs as _ :: _)) = x :: s :: separate s xs
497 | separate _ xs = xs;
499 (*make the list [x, x, ..., x] of length n*)
500 fun replicate n (x: 'a) : 'a list =
501 let fun rep (0, xs) = xs
502 | rep (n, xs) = rep (n - 1, x :: xs)
504 if n < 0 then raise Subscript
508 fun translate_string f = String.translate (f o String.str);
510 (*multiply [a, b, c, ...] * [xs, ys, zs, ...]*)
511 fun multiply [] _ = []
512 | multiply (x :: xs) yss = map (cons x) yss @ multiply xs yss;
515 fun product _ [] = []
517 | product (x :: xs) ys = map (pair x) ys @ product xs ys;
522 (*copy the list preserving elements that satisfy the predicate*)
523 val filter = List.filter;
524 fun filter_out f = filter (not o f);
525 val map_filter = List.mapPartial;
530 exception UnequalLengths;
532 fun map2 _ [] [] = []
533 | map2 f (x :: xs) (y :: ys) = f x y :: map2 f xs ys
534 | map2 _ _ _ = raise UnequalLengths;
536 fun fold2 f [] [] z = z
537 | fold2 f (x :: xs) (y :: ys) z = fold2 f xs ys (f x y z)
538 | fold2 f _ _ _ = raise UnequalLengths;
540 fun zip_options (x :: xs) (SOME y :: ys) = (x, y) :: zip_options xs ys
541 | zip_options (_ :: xs) (NONE :: ys) = zip_options xs ys
542 | zip_options _ [] = []
543 | zip_options [] _ = raise UnequalLengths;
545 (*combine two lists forming a list of pairs:
546 [x1, ..., xn] ~~ [y1, ..., yn] ===> [(x1, y1), ..., (xn, yn)]*)
548 | (x :: xs) ~~ (y :: ys) = (x, y) :: (xs ~~ ys)
549 | _ ~~ _ = raise UnequalLengths;
551 (*inverse of ~~; the old 'split':
552 [(x1, y1), ..., (xn, yn)] ===> ([x1, ..., xn], [y1, ..., yn])*)
553 val split_list = ListPair.unzip;
556 (* prefixes, suffixes *)
558 fun is_prefix _ [] _ = true
559 | is_prefix eq (x :: xs) (y :: ys) = eq (x, y) andalso is_prefix eq xs ys
560 | is_prefix eq _ _ = false;
562 (* [x1, ..., xi, ..., xn] ---> ([x1, ..., x(i-1)], [xi, ..., xn])
563 where xi is the first element that does not satisfy the predicate*)
564 fun take_prefix (pred : 'a -> bool) (xs: 'a list) : 'a list * 'a list =
565 let fun take (rxs, []) = (rev rxs, [])
566 | take (rxs, x :: xs) =
567 if pred x then take(x :: rxs, xs) else (rev rxs, x :: xs)
570 fun chop_prefix eq ([], ys) = ([], ([], ys))
571 | chop_prefix eq (xs, []) = ([], (xs, []))
572 | chop_prefix eq (xs as x :: xs', ys as y :: ys') =
574 let val (ps', xys'') = chop_prefix eq (xs', ys')
575 in (x :: ps', xys'') end
578 (* [x1, ..., xi, ..., xn] ---> ([x1, ..., xi], [x(i+1), ..., xn])
579 where xi is the last element that does not satisfy the predicate*)
580 fun take_suffix _ [] = ([], [])
581 | take_suffix pred (x :: xs) =
582 (case take_suffix pred xs of
583 ([], sffx) => if pred x then ([], x :: sffx) else ([x], sffx)
584 | (prfx, sffx) => (x :: prfx, sffx));
586 fun prefixes1 [] = []
587 | prefixes1 (x :: xs) = map (cons x) ([] :: prefixes1 xs);
589 fun prefixes xs = [] :: prefixes1 xs;
591 fun suffixes1 xs = map rev (prefixes1 (rev xs));
592 fun suffixes xs = [] :: suffixes1 xs;
598 fun inc i = (i := ! i + 1; ! i);
599 fun dec i = (i := ! i - 1; ! i);
602 (* lists of integers *)
604 (*make the list [from, from + 1, ..., to]*)
606 if i > j then [] else i :: (i + 1 upto j);
608 (*make the list [from, from - 1, ..., to]*)
610 if i < j then [] else i :: (i - 1 downto j);
613 (* convert integers to strings *)
615 (*expand the number in the given base;
616 example: radixpand (2, 8) gives [1, 0, 0, 0]*)
617 fun radixpand (base, num) : int list =
619 fun radix (n, tail) =
620 if n < base then n :: tail
621 else radix (n div base, (n mod base) :: tail)
622 in radix (num, []) end;
624 (*expands a number into a string of characters starting from "zerochar";
625 example: radixstring (2, "0", 8) gives "1000"*)
626 fun radixstring (base, zerochar, num) =
627 let val offset = ord zerochar;
628 fun chrof n = chr (offset + n)
629 in implode (map chrof (radixpand (base, num))) end;
632 val string_of_int = Int.toString;
634 fun signed_string_of_int i =
635 if i < 0 then "-" ^ string_of_int (~ i) else string_of_int i;
637 fun string_of_indexname (a, 0) = a
638 | string_of_indexname (a, i) = a ^ "_" ^ string_of_int i;
643 fun read_intinf radix cs =
646 val limit = zero + radix;
647 fun scan (num, []) = (num, [])
648 | scan (num, c :: cs) =
649 if zero <= ord c andalso ord c < limit then
650 scan (IntInf.fromInt radix * num + IntInf.fromInt (ord c - zero), cs)
652 in scan (IntInf.fromInt 0, cs) end;
654 fun read_int cs = apfst IntInf.toInt (read_intinf 10 cs);
656 fun oct_char s = chr (IntInf.toInt (#1 (read_intinf 8 (explode s))));
662 (* functions tuned for strings, avoiding explode *)
664 fun nth_string str i =
665 (case try String.substring (str, i, 1) of
667 | NONE => raise Subscript);
669 fun fold_string f str x0 =
673 if i < n then iter (f (String.substring (str, i, 1)) x, i + 1) else x;
676 fun exists_string pred str =
679 fun ex i = i < n andalso (pred (String.substring (str, i, 1)) orelse ex (i + 1));
682 fun forall_string pred = not o exists_string (not o pred);
684 (*enclose in brackets*)
685 fun enclose lpar rpar str = lpar ^ str ^ rpar;
686 fun unenclose str = String.substring (str, 1, size str - 2);
688 (*simple quoting (does not escape special chars)*)
689 val quote = enclose "\"" "\"";
691 (*space_implode "..." (explode "hello") = "h...e...l...l...o"*)
692 fun space_implode a bs = implode (separate a bs);
694 val commas = space_implode ", ";
695 val commas_quote = commas o map quote;
697 (*concatenate messages, one per line, into a string*)
698 val cat_lines = space_implode "\n";
700 (*space_explode "." "h.e..l.lo" = ["h", "e", "", "l", "lo"]*)
701 fun space_explode _ "" = []
702 | space_explode sep s = String.fields (fn c => str c = sep) s;
704 val split_lines = space_explode "\n";
706 fun prefix_lines "" txt = txt
707 | prefix_lines prfx txt = txt |> split_lines |> map (fn s => prfx ^ s) |> cat_lines;
713 fun untab pos [] ys = rev ys
714 | untab pos ("\n" :: xs) ys = untab 0 xs ("\n" :: ys)
715 | untab pos ("\t" :: xs) ys =
716 let val d = tab_width - (pos mod tab_width)
717 in untab (pos + d) xs (funpow d (cons " ") ys) end
718 | untab pos (c :: xs) ys = untab (pos + 1) xs (c :: ys);
720 if not (exists (fn c => c = "\t") chs) then chs
724 fun prefix prfx s = prfx ^ s;
725 fun suffix sffx s = s ^ sffx;
727 fun unprefix prfx s =
728 if String.isPrefix prfx s then String.substring (s, size prfx, size s - size prfx)
729 else raise Fail "unprefix";
731 fun unsuffix sffx s =
732 if String.isSuffix sffx s then String.substring (s, 0, size s - size sffx)
733 else raise Fail "unsuffix";
735 fun replicate_string 0 _ = ""
736 | replicate_string 1 a = a
737 | replicate_string k a =
738 if k mod 2 = 0 then replicate_string (k div 2) (a ^ a)
739 else replicate_string (k div 2) (a ^ a) ^ a;
743 (** lists as sets -- see also Pure/General/ord_list.ML **)
745 (*canonical member, insert, remove*)
746 fun member eq list x =
749 | memb (y :: ys) = eq (x, y) orelse memb ys;
752 fun insert eq x xs = if member eq xs x then xs else x :: xs;
753 fun remove eq x xs = if member eq xs x then filter_out (fn y => eq (x, y)) xs else xs;
754 fun update eq x xs = cons x (remove eq x xs);
756 fun subtract eq = fold (remove eq);
758 fun merge _ ([], ys) = ys
759 | merge eq (xs, ys) = fold_rev (insert eq) ys xs;
761 (*old-style infixes*)
762 fun x mem xs = member (op =) xs x;
763 fun (x: int) mem_int xs = member (op =) xs x;
764 fun (x: string) mem_string xs = member (op =) xs x;
767 (*union of sets represented as lists: no repetitions*)
770 | (x :: xs) union ys = xs union (insert (op =) x ys);
772 (*union of sets, optimized version for ints*)
773 fun (xs:int list) union_int [] = xs
774 | [] union_int ys = ys
775 | (x :: xs) union_int ys = xs union_int (insert (op =) x ys);
777 (*union of sets, optimized version for strings*)
778 fun (xs:string list) union_string [] = xs
779 | [] union_string ys = ys
780 | (x :: xs) union_string ys = xs union_string (insert (op =) x ys);
782 (*generalized union*)
783 fun gen_union eq (xs, []) = xs
784 | gen_union eq ([], ys) = ys
785 | gen_union eq (x :: xs, ys) = gen_union eq (xs, insert eq x ys);
790 | (x :: xs) inter ys =
791 if x mem ys then x :: (xs inter ys) else xs inter ys;
793 (*intersection, optimized version for ints*)
794 fun ([]:int list) inter_int ys = []
795 | (x :: xs) inter_int ys =
796 if x mem_int ys then x :: (xs inter_int ys) else xs inter_int ys;
798 (*intersection, optimized version for strings *)
799 fun ([]:string list) inter_string ys = []
800 | (x :: xs) inter_string ys =
801 if x mem_string ys then x :: (xs inter_string ys) else xs inter_string ys;
803 (*generalized intersection*)
804 fun gen_inter eq ([], ys) = []
805 | gen_inter eq (x::xs, ys) =
806 if member eq ys x then x :: gen_inter eq (xs, ys)
807 else gen_inter eq (xs, ys);
811 fun [] subset ys = true
812 | (x :: xs) subset ys = x mem ys andalso xs subset ys;
814 (*subset, optimized version for ints*)
815 fun ([]: int list) subset_int ys = true
816 | (x :: xs) subset_int ys = x mem_int ys andalso xs subset_int ys;
818 (*subset, optimized version for strings*)
819 fun ([]: string list) subset_string ys = true
820 | (x :: xs) subset_string ys = x mem_string ys andalso xs subset_string ys;
823 fun eq_set (xs, ys) =
824 xs = ys orelse (xs subset ys andalso ys subset xs);
826 (*set equality for strings*)
827 fun eq_set_string ((xs: string list), ys) =
828 xs = ys orelse (xs subset_string ys andalso ys subset_string xs);
830 fun gen_subset eq (xs, ys) = forall (member eq ys) xs;
832 fun gen_eq_set eq (xs, ys) =
833 eq_list eq (xs, ys) orelse
834 (gen_subset eq (xs, ys) andalso gen_subset (eq o swap) (ys, xs));
837 (*removing an element from a list WITHOUT duplicates*)
838 fun (y :: ys) \ x = if x = y then ys else y :: (ys \ x)
840 fun ys \\ xs = foldl (op \) (ys,xs);
843 (*makes a list of the distinct members of the input; preserves order, takes
844 first of equal elements*)
845 fun distinct eq lst =
847 fun dist (rev_seen, []) = rev rev_seen
848 | dist (rev_seen, x :: xs) =
849 if member eq rev_seen x then dist (rev_seen, xs)
850 else dist (x :: rev_seen, xs);
851 in dist ([], lst) end;
853 (*returns a list containing all repeated elements exactly once; preserves
854 order, takes first of equal elements*)
855 fun duplicates eq lst =
857 fun dups (rev_dups, []) = rev rev_dups
858 | dups (rev_dups, x :: xs) =
859 if member eq rev_dups x orelse not (member eq xs x) then
861 else dups (x :: rev_dups, xs);
862 in dups ([], lst) end;
864 fun has_duplicates eq =
867 | dups (x :: xs) = member eq xs x orelse dups xs;
872 (** lists as multisets **)
874 fun remove1 _ _ [] = raise Empty
875 | remove1 eq y (x::xs) = if eq (y, x) then xs else x :: remove1 eq y xs;
877 fun submultiset _ ([], _) = true
878 | submultiset eq (x :: xs, ys) = member eq ys x andalso submultiset eq (xs, remove1 eq x ys);
884 fun is_equal EQUAL = true
885 | is_equal _ = false;
887 fun rev_order LESS = GREATER
888 | rev_order EQUAL = EQUAL
889 | rev_order GREATER = LESS;
891 (*assume rel is a linear strict order*)
892 fun make_ord rel (x, y) =
893 if rel (x, y) then LESS
894 else if rel (y, x) then GREATER
897 val int_ord = Int.compare;
898 val string_ord = String.compare;
900 fun fast_string_ord (s1, s2) =
901 (case int_ord (size s1, size s2) of EQUAL => string_ord (s1, s2) | ord => ord);
903 fun option_ord ord (SOME x, SOME y) = ord (x, y)
904 | option_ord _ (NONE, NONE) = EQUAL
905 | option_ord _ (NONE, SOME _) = LESS
906 | option_ord _ (SOME _, NONE) = GREATER;
908 (*lexicographic product*)
909 fun prod_ord a_ord b_ord ((x, y), (x', y')) =
910 (case a_ord (x, x') of EQUAL => b_ord (y, y') | ord => ord);
912 (*dictionary order -- in general NOT well-founded!*)
913 fun dict_ord elem_ord (x :: xs, y :: ys) =
914 (case elem_ord (x, y) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord)
915 | dict_ord _ ([], []) = EQUAL
916 | dict_ord _ ([], _ :: _) = LESS
917 | dict_ord _ (_ :: _, []) = GREATER;
919 (*lexicographic product of lists*)
920 fun list_ord elem_ord (xs, ys) =
921 (case int_ord (length xs, length ys) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord);
926 (*quicksort -- stable, i.e. does not reorder equal elements*)
927 fun quicksort unique ord =
930 | qsort (xs as [_]) = xs
931 | qsort (xs as [x, y]) =
934 | EQUAL => if unique then [x] else xs
937 let val (lts, eqs, gts) = part (nth xs (length xs div 2)) xs
938 in qsort lts @ eqs @ qsort gts end
939 and part _ [] = ([], [], [])
940 | part pivot (x :: xs) = add (ord (x, pivot)) x (part pivot xs)
941 and add LESS x (lts, eqs, gts) = (x :: lts, eqs, gts)
942 | add EQUAL x (lts, [], gts) = (lts, [x], gts)
943 | add EQUAL x (res as (lts, eqs, gts)) = if unique then res else (lts, x :: eqs, gts)
944 | add GREATER x (lts, eqs, gts) = (lts, eqs, x :: gts);
947 fun sort ord = quicksort false ord;
948 fun sort_distinct ord = quicksort true ord;
950 val sort_strings = sort string_ord;
951 fun sort_wrt sel xs = sort (string_ord o pairself sel) xs;
955 (** random numbers **)
959 fun rmod x y = x - y * Real.realFloor (x / y);
963 val m = 2147483647.0;
964 val random_seed = ref 1.0;
967 fun random () = CRITICAL (fn () =>
968 let val r = rmod (a * ! random_seed) m
969 in (random_seed := r; r) end);
973 fun random_range l h =
974 if h < l orelse l < 0 then raise RANDOM
975 else l + Real.floor (rmod (random ()) (real (h - l + 1)));
977 fun one_of xs = nth xs (random_range 0 (length xs - 1));
981 val sum = foldl op + (0, map fst xs);
982 fun pick n ((k: int, x) :: xs) =
983 if n <= k then x else pick (n - k) xs
984 in pick (random_range 1 sum) xs end;
990 fun divide_and_conquer decomp x =
991 let val (ys, recomb) = decomp x
992 in recomb (map (divide_and_conquer decomp) ys) end;
995 (*Partition a list into buckets [ bi, b(i+1), ..., bj ]
996 putting x in bk if p(k)(x) holds. Preserve order of elements if possible.*)
997 fun partition_list p i j =
1000 (case xs of [] => []
1001 | _ => raise Fail "partition_list")
1003 let val (ns, rest) = List.partition (p k) xs;
1004 in ns :: part(k+1)rest end
1007 fun partition_eq (eq:'a * 'a -> bool) =
1011 let val (xs, xs') = List.partition (fn y => eq (x, y)) ys
1012 in (x::xs)::(part xs') end
1017 (* generating identifiers *)
1019 (** Freshly generated identifiers; supplied prefix MUST start with a letter **)
1021 (*Maps 0-61 to A-Z, a-z, 0-9; exclude _ or ' to avoid clash with internal/unusual indentifiers*)
1023 if i<26 then chr (ord "A" + i)
1024 else if i<52 then chr (ord "a" + i - 26)
1025 else chr (ord "0" + i - 52);
1027 val char_vec = Vector.tabulate (62, gensym_char);
1028 fun newid n = implode (map (fn i => Vector.sub (char_vec, i)) (radixpand (62, n)));
1030 val gensym_seed = ref 0;
1033 fun gensym pre = pre ^ newid (NAMED_CRITICAL "gensym" (fn () => inc gensym_seed));
1037 (* stamps and serial numbers *)
1039 type stamp = unit ref;
1040 val stamp: unit -> stamp = ref;
1043 local val count = ref 0
1044 in fun serial () = NAMED_CRITICAL "serial" (fn () => inc count) end;
1046 val serial_string = string_of_int o serial;
1049 (* generic objects *)
1051 (*note that the builtin exception datatype may be extended by new
1052 constructors at any time*)
1053 structure Object = struct type T = exn end;
1057 structure BasicLibrary: BASIC_LIBRARY = Library;