src/Pure/library.ML
author wenzelm
Sun Nov 05 21:44:35 2006 +0100 (2006-11-05)
changeset 21182 747ff99b35ee
parent 21118 d9789a87825d
child 21335 6b9d4a19a3a8
permissions -rw-r--r--
removed obsolete first_duplicate;
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(*  Title:      Pure/library.ML
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Author:     Markus Wenzel, TU Muenchen
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Basic library: functions, options, pairs, booleans, lists, integers,
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strings, lists as sets, balanced trees, orders, current directory, misc.
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*)
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infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
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infix 2 ?;
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infix 3 o oo ooo oooo;
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infix 4 ~~ upto downto;
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infix orf andf \ \\ mem mem_int mem_string union union_int
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  union_string inter inter_int inter_string subset subset_int subset_string;
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signature BASIC_LIBRARY =
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sig
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  (*functions*)
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  val I: 'a -> 'a
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  val K: 'a -> 'b -> 'a
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  val curry: ('a * 'b -> 'c) -> 'a -> 'b -> 'c
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  val uncurry: ('a -> 'b -> 'c) -> 'a * 'b -> 'c
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  val |> : 'a * ('a -> 'b) -> 'b
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  val |-> : ('c * 'a) * ('c -> 'a -> 'b) -> 'b
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  val ||> : ('c * 'a) * ('a -> 'b) -> 'c * 'b
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  val ||>> : ('c * 'a) * ('a -> 'd * 'b) -> ('c * 'd) * 'b
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  val |>> : ('a * 'c) * ('a -> 'b) -> 'b * 'c
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  val |>>> : ('a * 'c) * ('a -> 'b * 'd) -> 'b * ('c * 'd)
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  val #> : ('a -> 'b) * ('b -> 'c) -> 'a -> 'c
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  val #-> : ('a -> 'c * 'b) * ('c -> 'b -> 'd) -> 'a -> 'd
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  val ? : ('a -> bool) * ('a -> 'a) -> 'a -> 'a
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  val ` : ('b -> 'a) -> 'b -> 'a * 'b
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  val tap: ('b -> 'a) -> 'b -> 'b
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  val oo: ('a -> 'b) * ('c -> 'd -> 'a) -> 'c -> 'd -> 'b
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  val ooo: ('a -> 'b) * ('c -> 'd -> 'e -> 'a) -> 'c -> 'd -> 'e -> 'b
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  val oooo: ('a -> 'b) * ('c -> 'd -> 'e -> 'f -> 'a) -> 'c -> 'd -> 'e -> 'f -> 'b
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  val funpow: int -> ('a -> 'a) -> 'a -> 'a
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  (*options*)
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  val the: 'a option -> 'a
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  val these: 'a list option -> 'a list
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  val the_default: 'a -> 'a option -> 'a
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  val the_list: 'a option -> 'a list
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  val is_some: 'a option -> bool
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  val is_none: 'a option -> bool
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  val perhaps: ('a -> 'a option) -> 'a -> 'a
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  (*exceptions*)
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  val try: ('a -> 'b) -> 'a -> 'b option
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  val can: ('a -> 'b) -> 'a -> bool
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  exception EXCEPTION of exn * string
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  val do_transform_failure: bool ref
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  val transform_failure: (exn -> exn) -> ('a -> 'b) -> 'a -> 'b
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  datatype 'a result = Result of 'a | Exn of exn
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  val capture: ('a -> 'b) -> 'a -> 'b result
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  val release: 'a result -> 'a
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  val get_result: 'a result -> 'a option
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  val get_exn: 'a result -> exn option
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  (*errors*)
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  exception SYS_ERROR of string
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  val sys_error: string -> 'a
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  exception ERROR of string
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  val error: string -> 'a
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  val cat_error: string -> string -> 'a
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  val assert: bool -> string -> unit
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  val deny: bool -> string -> unit
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  val assert_all: ('a -> bool) -> 'a list -> ('a -> string) -> unit
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  (*pairs*)
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  val pair: 'a -> 'b -> 'a * 'b
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  val rpair: 'a -> 'b -> 'b * 'a
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  val fst: 'a * 'b -> 'a
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  val snd: 'a * 'b -> 'b
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  val eq_fst: ('a * 'c -> bool) -> ('a * 'b) * ('c * 'd) -> bool
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  val eq_snd: ('b * 'd -> bool) -> ('a * 'b) * ('c * 'd) -> bool
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  val eq_pair: ('a * 'c -> bool) -> ('b * 'd -> bool) -> ('a * 'b) * ('c * 'd) -> bool
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  val swap: 'a * 'b -> 'b * 'a
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  val apfst: ('a -> 'b) -> 'a * 'c -> 'b * 'c
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  val apsnd: ('a -> 'b) -> 'c * 'a -> 'c * 'b
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  val pairself: ('a -> 'b) -> 'a * 'a -> 'b * 'b
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  val string_of_pair: ('a -> string) -> ('b -> string) -> 'a * 'b -> string
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  (*booleans*)
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  val equal: ''a -> ''a -> bool
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  val not_equal: ''a -> ''a -> bool
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  val orf: ('a -> bool) * ('a -> bool) -> 'a -> bool
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  val andf: ('a -> bool) * ('a -> bool) -> 'a -> bool
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  val exists: ('a -> bool) -> 'a list -> bool
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  val forall: ('a -> bool) -> 'a list -> bool
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  val set: bool ref -> bool
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  val reset: bool ref -> bool
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  val toggle: bool ref -> bool
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  val change: 'a ref -> ('a -> 'a) -> unit
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  val setmp: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
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  val conditional: bool -> (unit -> unit) -> unit
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  (*lists*)
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  exception UnequalLengths
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  val cons: 'a -> 'a list -> 'a list
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  val single: 'a -> 'a list
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  val the_single: 'a list -> 'a
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  val singleton: ('a list -> 'b list) -> 'a -> 'b
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  val append: 'a list -> 'a list -> 'a list
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  val apply: ('a -> 'a) list -> 'a -> 'a
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  val fold: ('a -> 'b -> 'b) -> 'a list -> 'b -> 'b
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  val fold_rev: ('a -> 'b -> 'b) -> 'a list -> 'b -> 'b
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  val fold_map: ('a -> 'b -> 'c * 'b) -> 'a list -> 'b -> 'c list * 'b
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  val foldr1: ('a * 'a -> 'a) -> 'a list -> 'a
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  val foldl_map: ('a * 'b -> 'a * 'c) -> 'a * 'b list -> 'a * 'c list
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  val flat: 'a list list -> 'a list
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  val maps: ('a -> 'b list) -> 'a list -> 'b list
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  val unflat: 'a list list -> 'b list -> 'b list list
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  val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
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  val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
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  val chop: int -> 'a list -> 'a list * 'a list
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  val dropwhile: ('a -> bool) -> 'a list -> 'a list
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  val nth: 'a list -> int -> 'a
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  val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
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  val nth_list: 'a list list -> int -> 'a list
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  val map_index: (int * 'a -> 'b) -> 'a list -> 'b list
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  val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
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  val split_last: 'a list -> 'a list * 'a
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  val find_index: ('a -> bool) -> 'a list -> int
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  val find_index_eq: ''a -> ''a list -> int
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  val find_first: ('a -> bool) -> 'a list -> 'a option
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  val get_index: ('a -> 'b option) -> 'a list -> (int * 'b) option
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  val get_first: ('a -> 'b option) -> 'a list -> 'b option
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  val eq_list: ('a * 'b -> bool) -> 'a list * 'b list -> bool
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  val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
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  val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
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  val zip_options: 'a list -> 'b option list -> ('a * 'b) list
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  val ~~ : 'a list * 'b list -> ('a * 'b) list
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  val split_list: ('a * 'b) list -> 'a list * 'b list
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  val separate: 'a -> 'a list -> 'a list
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  val replicate: int -> 'a -> 'a list
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  val multiply: 'a list -> 'a list list -> 'a list list
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  val product: 'a list -> 'b list -> ('a * 'b) list
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  val filter: ('a -> bool) -> 'a list -> 'a list
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  val filter_out: ('a -> bool) -> 'a list -> 'a list
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  val map_filter: ('a -> 'b option) -> 'a list -> 'b list
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  val is_prefix: ('a * 'a -> bool) -> 'a list -> 'a list -> bool
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  val take_prefix: ('a -> bool) -> 'a list -> 'a list * 'a list
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  val chop_prefix: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list * ('a list * 'b list)
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  val take_suffix: ('a -> bool) -> 'a list -> 'a list * 'a list
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  val prefixes1: 'a list -> 'a list list
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  val prefixes: 'a list -> 'a list list
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  val suffixes1: 'a list -> 'a list list
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  val suffixes: 'a list -> 'a list list
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  (*integers*)
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  val gcd: IntInf.int * IntInf.int -> IntInf.int
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  val lcm: IntInf.int * IntInf.int -> IntInf.int
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  val inc: int ref -> int
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  val dec: int ref -> int
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  val upto: int * int -> int list
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  val downto: int * int -> int list
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  val downto0: int list * int -> bool
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  val radixpand: int * int -> int list
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  val radixstring: int * string * int -> string
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  val string_of_int: int -> string
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  val string_of_indexname: string * int -> string
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  val read_intinf: int -> string list -> IntInf.int * string list
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  val read_int: string list -> int * string list
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  val oct_char: string -> string
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  (*strings*)
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  val nth_string: string -> int -> string
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  val fold_string: (string -> 'a -> 'a) -> string -> 'a -> 'a
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  val exists_string: (string -> bool) -> string -> bool
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  val forall_string: (string -> bool) -> string -> bool
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  val enclose: string -> string -> string -> string
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  val unenclose: string -> string
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  val quote: string -> string
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  val space_implode: string -> string list -> string
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  val commas: string list -> string
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  val commas_quote: string list -> string
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  val cat_lines: string list -> string
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  val space_explode: string -> string -> string list
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  val split_lines: string -> string list
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  val prefix_lines: string -> string -> string
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  val untabify: string list -> string list
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  val prefix: string -> string -> string
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  val suffix: string -> string -> string
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  val unprefix: string -> string -> string
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  val unsuffix: string -> string -> string
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  val replicate_string: int -> string -> string
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  val translate_string: (string -> string) -> string -> string
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  val string_of_list: ('a -> string) -> 'a list -> string
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  val string_of_option: ('a -> string) -> 'a option -> string
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  (*lists as sets -- see also Pure/General/ord_list.ML*)
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  val member: ('b * 'a -> bool) -> 'a list -> 'b -> bool
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  val insert: ('a * 'a -> bool) -> 'a -> 'a list -> 'a list
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  val remove: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
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  val subtract: ('b * 'a -> bool) -> 'b list -> 'a list -> 'a list
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  val merge: ('a * 'a -> bool) -> 'a list * 'a list -> 'a list
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  val mem: ''a * ''a list -> bool
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  val mem_int: int * int list -> bool
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  val mem_string: string * string list -> bool
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  val union: ''a list * ''a list -> ''a list
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  val union_int: int list * int list -> int list
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  val union_string: string list * string list -> string list
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  val gen_union: ('a * 'a -> bool) -> 'a list * 'a list -> 'a list
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  val gen_inter: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list
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  val inter: ''a list * ''a list -> ''a list
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  val inter_int: int list * int list -> int list
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  val inter_string: string list * string list -> string list
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  val subset: ''a list * ''a list -> bool
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  val subset_int: int list * int list -> bool
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  val subset_string: string list * string list -> bool
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  val eq_set: ''a list * ''a list -> bool
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  val eq_set_string: string list * string list -> bool
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  val gen_subset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
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  val gen_eq_set: ('a * 'b -> bool) -> 'a list * 'b list -> bool
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  val \ : ''a list * ''a -> ''a list
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  val \\ : ''a list * ''a list -> ''a list
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  val distinct: ('a * 'a -> bool) -> 'a list -> 'a list
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  val duplicates: ('a * 'a -> bool) -> 'a list -> 'a list
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  val has_duplicates: ('a * 'a -> bool) -> 'a list -> bool
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  (*lists as tables -- see also Pure/General/alist.ML*)
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  val gen_merge_lists: ('a * 'a -> bool) -> 'a list -> 'a list -> 'a list
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  val merge_lists: ''a list -> ''a list -> ''a list
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  val merge_alists: (''a * 'b) list -> (''a * 'b) list -> (''a * 'b) list
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  (*balanced trees*)
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  exception Balance
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  val fold_bal: ('a * 'a -> 'a) -> 'a list -> 'a
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  val access_bal: ('a -> 'a) * ('a -> 'a) * 'a -> int -> int -> 'a
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  val accesses_bal: ('a -> 'a) * ('a -> 'a) * 'a -> int -> 'a list
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  (*orders*)
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  val is_equal: order -> bool
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  val rev_order: order -> order
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  val make_ord: ('a * 'a -> bool) -> 'a * 'a -> order
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  val int_ord: int * int -> order
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  val string_ord: string * string -> order
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  val fast_string_ord: string * string -> order
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  val option_ord: ('a * 'b -> order) -> 'a option * 'b option -> order
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  val prod_ord: ('a * 'b -> order) -> ('c * 'd -> order) -> ('a * 'c) * ('b * 'd) -> order
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  val dict_ord: ('a * 'b -> order) -> 'a list * 'b list -> order
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  val list_ord: ('a * 'b -> order) -> 'a list * 'b list -> order
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  val sort: ('a * 'a -> order) -> 'a list -> 'a list
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  val sort_distinct: ('a * 'a -> order) -> 'a list -> 'a list
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  val sort_strings: string list -> string list
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  val sort_wrt: ('a -> string) -> 'a list -> 'a list
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  (*random numbers*)
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  exception RANDOM
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  val random: unit -> real
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  val random_range: int -> int -> int
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  val one_of: 'a list -> 'a
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  val frequency: (int * 'a) list -> 'a
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  (*current directory*)
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  val cd: string -> unit
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  val pwd: unit -> string
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  (*misc*)
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  val divide_and_conquer: ('a -> 'a list * ('b list -> 'b)) -> 'a -> 'b
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  val partition_eq: ('a * 'a -> bool) -> 'a list -> 'a list list
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  val partition_list: (int -> 'a -> bool) -> int -> int -> 'a list -> 'a list list
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  val gensym: string -> string
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  val scanwords: (string -> bool) -> string list -> string list
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  type stamp
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  val stamp: unit -> stamp
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  type serial
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  val serial: unit -> serial
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  val serial_string: unit -> string
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  structure Object: sig type T end
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end;
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signature LIBRARY =
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sig
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  include BASIC_LIBRARY
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  val foldl: ('a * 'b -> 'a) -> 'a * 'b list -> 'a
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  val foldr: ('a * 'b -> 'b) -> 'a list * 'b -> 'b
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  val take: int * 'a list -> 'a list
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  val drop: int * 'a list -> 'a list
skalberg@15570
   283
  val last_elem: 'a list -> 'a
skalberg@15570
   284
  val seq: ('a -> unit) -> 'a list -> unit
skalberg@15570
   285
end;
skalberg@15570
   286
wenzelm@15745
   287
structure Library: LIBRARY =
clasohm@1364
   288
struct
clasohm@0
   289
wenzelm@4995
   290
wenzelm@233
   291
(** functions **)
clasohm@0
   292
wenzelm@16842
   293
fun I x = x;
wenzelm@16842
   294
fun K x = fn _ => x;
wenzelm@233
   295
fun curry f x y = f (x, y);
wenzelm@233
   296
fun uncurry f (x, y) = f x y;
clasohm@0
   297
wenzelm@16705
   298
(*reverse application and structured results*)
wenzelm@16705
   299
fun x |> f = f x;
wenzelm@16705
   300
fun (x, y) |-> f = f x y;
wenzelm@16705
   301
fun (x, y) |>> f = (f x, y);
wenzelm@16705
   302
fun (x, y) ||> f = (x, f y);
wenzelm@16705
   303
fun (x, y) |>>> f = let val (x', z) = f x in (x', (y, z)) end;
wenzelm@16705
   304
fun (x, y) ||>> f = let val (z, y') = f y in ((x, z), y') end;
wenzelm@16842
   305
wenzelm@16842
   306
(*reverse composition*)
haftmann@16780
   307
fun f #> g = g o f;
wenzelm@16842
   308
fun f #-> g = uncurry g o f;
wenzelm@16842
   309
haftmann@17141
   310
(*conditional application*)
wenzelm@17545
   311
fun b ? f = fn x => if b x then f x else x;
haftmann@17141
   312
wenzelm@16842
   313
(*view results*)
wenzelm@16842
   314
fun `f = fn x => (f x, x);
wenzelm@17545
   315
fun tap f = fn x => (f x; x);
wenzelm@380
   316
wenzelm@16721
   317
(*composition with multiple args*)
wenzelm@16721
   318
fun (f oo g) x y = f (g x y);
wenzelm@16721
   319
fun (f ooo g) x y z = f (g x y z);
wenzelm@16721
   320
fun (f oooo g) x y z w = f (g x y z w);
wenzelm@16721
   321
wenzelm@233
   322
(*function exponentiation: f(...(f x)...) with n applications of f*)
wenzelm@233
   323
fun funpow n f x =
wenzelm@233
   324
  let fun rep (0, x) = x
wenzelm@233
   325
        | rep (n, x) = rep (n - 1, f x)
wenzelm@233
   326
  in rep (n, x) end;
wenzelm@160
   327
wenzelm@160
   328
wenzelm@233
   329
(** options **)
clasohm@0
   330
wenzelm@15970
   331
val the = Option.valOf;
wenzelm@17341
   332
haftmann@17153
   333
fun these (SOME x) = x
haftmann@17313
   334
  | these _ = [];
wenzelm@17341
   335
haftmann@17313
   336
fun the_default x (SOME y) = y
haftmann@17313
   337
  | the_default x _ = x;
wenzelm@17341
   338
haftmann@17313
   339
fun the_list (SOME x) = [x]
haftmann@17313
   340
  | the_list _ = []
wenzelm@15970
   341
wenzelm@15970
   342
fun is_some (SOME _) = true
wenzelm@15970
   343
  | is_some NONE = false;
wenzelm@15970
   344
wenzelm@15970
   345
fun is_none (SOME _) = false
wenzelm@15970
   346
  | is_none NONE = true;
wenzelm@15970
   347
wenzelm@18376
   348
fun perhaps f x = the_default x (f x);
wenzelm@18376
   349
wenzelm@19474
   350
wenzelm@17341
   351
(* exceptions *)
wenzelm@17341
   352
wenzelm@18681
   353
val do_transform_failure = ref true;
wenzelm@18681
   354
wenzelm@18681
   355
fun transform_failure exn f x =
wenzelm@18681
   356
  if ! do_transform_failure then
wenzelm@18681
   357
    f x handle Interrupt => raise Interrupt | e => raise exn e
wenzelm@18681
   358
  else f x;
wenzelm@18681
   359
wenzelm@17341
   360
exception EXCEPTION of exn * string;
wenzelm@6959
   361
wenzelm@6959
   362
skalberg@15531
   363
fun try f x = SOME (f x)
wenzelm@18681
   364
  handle Interrupt => raise Interrupt | _ => NONE;
wenzelm@6959
   365
wenzelm@6959
   366
fun can f x = is_some (try f x);
wenzelm@4139
   367
wenzelm@4139
   368
wenzelm@14868
   369
datatype 'a result =
wenzelm@14868
   370
  Result of 'a |
wenzelm@14868
   371
  Exn of exn;
wenzelm@14868
   372
wenzelm@14868
   373
fun capture f x = Result (f x) handle e => Exn e;
wenzelm@14868
   374
wenzelm@14868
   375
fun release (Result y) = y
wenzelm@14868
   376
  | release (Exn e) = raise e;
wenzelm@14868
   377
skalberg@15531
   378
fun get_result (Result x) = SOME x
skalberg@15531
   379
  | get_result _ = NONE;
wenzelm@14868
   380
skalberg@15531
   381
fun get_exn (Exn exn) = SOME exn
skalberg@15531
   382
  | get_exn _ = NONE;
wenzelm@14868
   383
wenzelm@14868
   384
wenzelm@18681
   385
(* errors *)
wenzelm@18681
   386
wenzelm@19542
   387
exception SYS_ERROR of string;
wenzelm@19542
   388
fun sys_error msg = raise SYS_ERROR msg;
wenzelm@19542
   389
wenzelm@18681
   390
exception ERROR of string;
wenzelm@18681
   391
fun error msg = raise ERROR msg;
wenzelm@18681
   392
wenzelm@18681
   393
fun cat_error "" msg = error msg
wenzelm@18681
   394
  | cat_error msg1 msg2 = error (msg1 ^ "\n" ^ msg2);
wenzelm@18681
   395
wenzelm@18681
   396
fun assert p msg = if p then () else error msg;
wenzelm@18681
   397
fun deny p msg = if p then error msg else ();
wenzelm@18681
   398
wenzelm@18681
   399
fun assert_all pred list msg =
wenzelm@18681
   400
  let
wenzelm@18681
   401
    fun ass [] = ()
wenzelm@18681
   402
      | ass (x :: xs) = if pred x then ass xs else error (msg x);
wenzelm@18681
   403
  in ass list end;
wenzelm@18681
   404
wenzelm@18681
   405
wenzelm@233
   406
(** pairs **)
wenzelm@233
   407
wenzelm@233
   408
fun pair x y = (x, y);
wenzelm@233
   409
fun rpair x y = (y, x);
wenzelm@233
   410
wenzelm@233
   411
fun fst (x, y) = x;
wenzelm@233
   412
fun snd (x, y) = y;
wenzelm@233
   413
haftmann@17498
   414
fun eq_fst eq ((x1, _), (x2, _)) = eq (x1, x2);
haftmann@17498
   415
fun eq_snd eq ((_, y1), (_, y2)) = eq (y1, y2);
haftmann@19454
   416
fun eq_pair eqx eqy ((x1, y1), (x2, y2)) = eqx (x1, x2) andalso eqy (y1, y2);
wenzelm@233
   417
wenzelm@233
   418
fun swap (x, y) = (y, x);
wenzelm@233
   419
wenzelm@4212
   420
(*apply function to components*)
wenzelm@233
   421
fun apfst f (x, y) = (f x, y);
wenzelm@233
   422
fun apsnd f (x, y) = (x, f y);
wenzelm@4212
   423
fun pairself f (x, y) = (f x, f y);
wenzelm@233
   424
webertj@19567
   425
fun string_of_pair f1 f2 (x, y) = "(" ^ f1 x ^ ", " ^ f2 y ^ ")";
wenzelm@233
   426
wenzelm@233
   427
wenzelm@233
   428
(** booleans **)
wenzelm@233
   429
wenzelm@233
   430
(* equality *)
wenzelm@233
   431
wenzelm@233
   432
fun equal x y = x = y;
wenzelm@233
   433
fun not_equal x y = x <> y;
wenzelm@233
   434
wenzelm@233
   435
(* operators for combining predicates *)
wenzelm@233
   436
wenzelm@16721
   437
fun p orf q = fn x => p x orelse q x;
wenzelm@16721
   438
fun p andf q = fn x => p x andalso q x;
wenzelm@233
   439
wenzelm@233
   440
(* predicates on lists *)
wenzelm@233
   441
wenzelm@233
   442
(*exists pred [x1, ..., xn] ===> pred x1 orelse ... orelse pred xn*)
wenzelm@233
   443
fun exists (pred: 'a -> bool) : 'a list -> bool =
wenzelm@233
   444
  let fun boolf [] = false
wenzelm@233
   445
        | boolf (x :: xs) = pred x orelse boolf xs
wenzelm@233
   446
  in boolf end;
wenzelm@233
   447
wenzelm@233
   448
(*forall pred [x1, ..., xn] ===> pred x1 andalso ... andalso pred xn*)
wenzelm@233
   449
fun forall (pred: 'a -> bool) : 'a list -> bool =
wenzelm@233
   450
  let fun boolf [] = true
wenzelm@233
   451
        | boolf (x :: xs) = pred x andalso boolf xs
wenzelm@233
   452
  in boolf end;
clasohm@0
   453
wenzelm@19644
   454
wenzelm@380
   455
(* flags *)
wenzelm@380
   456
wenzelm@380
   457
fun set flag = (flag := true; true);
wenzelm@380
   458
fun reset flag = (flag := false; false);
wenzelm@380
   459
fun toggle flag = (flag := not (! flag); ! flag);
wenzelm@380
   460
wenzelm@9118
   461
fun change r f = r := f (! r);
wenzelm@9118
   462
wenzelm@18712
   463
(*temporarily set flag during execution*)
wenzelm@2978
   464
fun setmp flag value f x =
wenzelm@2958
   465
  let
wenzelm@2958
   466
    val orig_value = ! flag;
wenzelm@18712
   467
    val _ = flag := value;
wenzelm@18712
   468
    val result = capture f x;
wenzelm@18712
   469
    val _ = flag := orig_value;
wenzelm@18712
   470
  in release result end;
wenzelm@2958
   471
wenzelm@19644
   472
wenzelm@11853
   473
(* conditional execution *)
wenzelm@11853
   474
wenzelm@11853
   475
fun conditional b f = if b then f () else ();
wenzelm@11853
   476
wenzelm@233
   477
wenzelm@233
   478
(** lists **)
wenzelm@233
   479
skalberg@15570
   480
exception UnequalLengths;
wenzelm@233
   481
wenzelm@233
   482
fun cons x xs = x :: xs;
wenzelm@20882
   483
wenzelm@5285
   484
fun single x = [x];
wenzelm@233
   485
wenzelm@20882
   486
fun the_single [x] = x
wenzelm@20882
   487
  | the_single _ = raise Empty;
wenzelm@20882
   488
wenzelm@20882
   489
fun singleton f x = the_single (f [x]);
wenzelm@19273
   490
wenzelm@4629
   491
fun append xs ys = xs @ ys;
wenzelm@4629
   492
wenzelm@5904
   493
fun apply [] x = x
wenzelm@5904
   494
  | apply (f :: fs) x = apply fs (f x);
wenzelm@5904
   495
wenzelm@233
   496
wenzelm@233
   497
(* fold *)
wenzelm@233
   498
wenzelm@16654
   499
fun fold f =
wenzelm@16654
   500
  let
wenzelm@16654
   501
    fun fold_aux [] y = y
wenzelm@16654
   502
      | fold_aux (x :: xs) y = fold_aux xs (f x y);
wenzelm@16654
   503
  in fold_aux end;
wenzelm@15760
   504
wenzelm@16654
   505
fun fold_rev f =
wenzelm@16654
   506
  let
wenzelm@16654
   507
    fun fold_aux [] y = y
wenzelm@16654
   508
      | fold_aux (x :: xs) y = f x (fold_aux xs y);
wenzelm@16654
   509
  in fold_aux end;
wenzelm@16654
   510
haftmann@16869
   511
fun fold_map f =
haftmann@16691
   512
  let
haftmann@16691
   513
    fun fold_aux [] y = ([], y)
haftmann@16691
   514
      | fold_aux (x :: xs) y =
haftmann@16691
   515
          let
wenzelm@16705
   516
            val (x', y') = f x y;
wenzelm@16705
   517
            val (xs', y'') = fold_aux xs y';
haftmann@16691
   518
          in (x' :: xs', y'') end;
haftmann@16691
   519
  in fold_aux end;
haftmann@16691
   520
wenzelm@233
   521
(*the following versions of fold are designed to fit nicely with infixes*)
clasohm@0
   522
wenzelm@233
   523
(*  (op @) (e, [x1, ..., xn])  ===>  ((e @ x1) @ x2) ... @ xn
wenzelm@233
   524
    for operators that associate to the left (TAIL RECURSIVE)*)
wenzelm@233
   525
fun foldl (f: 'a * 'b -> 'a) : 'a * 'b list -> 'a =
wenzelm@233
   526
  let fun itl (e, [])  = e
wenzelm@233
   527
        | itl (e, a::l) = itl (f(e, a), l)
wenzelm@233
   528
  in  itl end;
wenzelm@233
   529
wenzelm@233
   530
(*  (op @) ([x1, ..., xn], e)  ===>   x1 @ (x2 ... @ (xn @ e))
wenzelm@233
   531
    for operators that associate to the right (not tail recursive)*)
wenzelm@233
   532
fun foldr f (l, e) =
wenzelm@233
   533
  let fun itr [] = e
wenzelm@233
   534
        | itr (a::l) = f(a, itr l)
wenzelm@233
   535
  in  itr l  end;
wenzelm@233
   536
wenzelm@233
   537
(*  (op @) [x1, ..., xn]  ===>   x1 @ (x2 ... @ (x[n-1] @ xn))
wenzelm@233
   538
    for n > 0, operators that associate to the right (not tail recursive)*)
paulson@20443
   539
fun foldr1 f [] = raise Empty
wenzelm@20510
   540
  | foldr1 f l =
paulson@20443
   541
      let fun itr [x] = x
wenzelm@20510
   542
            | itr (x::l) = f(x, itr l)
paulson@20443
   543
      in  itr l  end;
wenzelm@233
   544
wenzelm@16705
   545
fun foldl_map f =
wenzelm@16705
   546
  let
wenzelm@16705
   547
    fun fold_aux (x, []) = (x, [])
wenzelm@16705
   548
      | fold_aux (x, y :: ys) =
wenzelm@16705
   549
          let
wenzelm@16705
   550
            val (x', y') = f (x, y);
wenzelm@16705
   551
            val (x'', ys') = fold_aux (x', ys);
wenzelm@16705
   552
          in (x'', y' :: ys') end;
wenzelm@16705
   553
  in fold_aux end;
wenzelm@16705
   554
wenzelm@233
   555
wenzelm@233
   556
(* basic list functions *)
wenzelm@233
   557
wenzelm@20510
   558
fun eq_list eq (list1, list2) =
haftmann@20348
   559
  let
wenzelm@20510
   560
    fun eq_lst (x :: xs, y :: ys) = eq (x, y) andalso eq_lst (xs, ys)
wenzelm@20510
   561
      | eq_lst _ = true;
wenzelm@20510
   562
  in length list1 = length list2 andalso eq_lst (list1, list2) end;
haftmann@20348
   563
wenzelm@19483
   564
fun maps f [] = []
wenzelm@19483
   565
  | maps f (x :: xs) = f x @ maps f xs;
wenzelm@19483
   566
wenzelm@19011
   567
fun chop 0 xs = ([], xs)
wenzelm@19011
   568
  | chop _ [] = ([], [])
wenzelm@19011
   569
  | chop n (x :: xs) = chop (n - 1) xs |>> cons x;
wenzelm@19011
   570
wenzelm@233
   571
(*take the first n elements from a list*)
wenzelm@233
   572
fun take (n, []) = []
wenzelm@233
   573
  | take (n, x :: xs) =
wenzelm@233
   574
      if n > 0 then x :: take (n - 1, xs) else [];
wenzelm@233
   575
wenzelm@233
   576
(*drop the first n elements from a list*)
wenzelm@233
   577
fun drop (n, []) = []
wenzelm@233
   578
  | drop (n, x :: xs) =
wenzelm@233
   579
      if n > 0 then drop (n - 1, xs) else x :: xs;
clasohm@0
   580
nipkow@4713
   581
fun dropwhile P [] = []
nipkow@4713
   582
  | dropwhile P (ys as x::xs) = if P x then dropwhile P xs else ys;
nipkow@4713
   583
wenzelm@233
   584
(*return nth element of a list, where 0 designates the first element;
wenzelm@18461
   585
  raise Subscript if list too short*)
haftmann@18011
   586
fun nth xs i = List.nth (xs, i);
wenzelm@233
   587
wenzelm@18461
   588
fun nth_list xss i = nth xss i handle Subscript => [];
wenzelm@18461
   589
haftmann@18011
   590
fun nth_map 0 f (x :: xs) = f x :: xs
haftmann@18011
   591
  | nth_map n f (x :: xs) = x :: nth_map (n - 1) f xs
haftmann@18011
   592
  | nth_map _ _ [] = raise Subscript;
wenzelm@11773
   593
haftmann@18514
   594
fun map_index f =
haftmann@18514
   595
  let
haftmann@18514
   596
    fun mapp _ [] = []
haftmann@18514
   597
      | mapp i (x :: xs) = f (i, x) :: mapp (i+1) xs
haftmann@18514
   598
  in mapp 0 end;
haftmann@18514
   599
haftmann@21118
   600
fun fold_index f =
haftmann@21118
   601
  let
haftmann@21118
   602
    fun fold_aux _ [] y = y
haftmann@21118
   603
      | fold_aux i (x :: xs) y = fold_aux (i+1) xs (f (i, x) y);
haftmann@21118
   604
  in fold_aux 0 end;
haftmann@21118
   605
skalberg@15570
   606
val last_elem = List.last;
wenzelm@233
   607
wenzelm@3762
   608
(*rear decomposition*)
skalberg@15570
   609
fun split_last [] = raise Empty
wenzelm@3762
   610
  | split_last [x] = ([], x)
wenzelm@3762
   611
  | split_last (x :: xs) = apfst (cons x) (split_last xs);
wenzelm@3762
   612
wenzelm@4212
   613
(*find the position of an element in a list*)
wenzelm@4212
   614
fun find_index pred =
wenzelm@4212
   615
  let fun find _ [] = ~1
wenzelm@4212
   616
        | find n (x :: xs) = if pred x then n else find (n + 1) xs;
wenzelm@4212
   617
  in find 0 end;
wenzelm@3762
   618
wenzelm@4224
   619
fun find_index_eq x = find_index (equal x);
wenzelm@4212
   620
wenzelm@4212
   621
(*find first element satisfying predicate*)
skalberg@15531
   622
fun find_first _ [] = NONE
wenzelm@4212
   623
  | find_first pred (x :: xs) =
skalberg@15531
   624
      if pred x then SOME x else find_first pred xs;
wenzelm@233
   625
wenzelm@4916
   626
(*get first element by lookup function*)
skalberg@15531
   627
fun get_first _ [] = NONE
wenzelm@4916
   628
  | get_first f (x :: xs) =
wenzelm@4916
   629
      (case f x of
skalberg@15531
   630
        NONE => get_first f xs
wenzelm@4916
   631
      | some => some);
wenzelm@4916
   632
haftmann@19233
   633
fun get_index f =
haftmann@19233
   634
  let
haftmann@19233
   635
    fun get _ [] = NONE
wenzelm@19461
   636
      | get i (x :: xs) =
haftmann@19233
   637
          case f x
wenzelm@19461
   638
           of NONE => get (i + 1) xs
haftmann@19233
   639
            | SOME y => SOME (i, y)
haftmann@19233
   640
  in get 0 end;
haftmann@19233
   641
skalberg@15531
   642
val flat = List.concat;
wenzelm@233
   643
wenzelm@12136
   644
fun unflat (xs :: xss) ys =
wenzelm@19424
   645
      let val (ps, qs) = chop (length xs) ys
nipkow@13629
   646
      in ps :: unflat xss qs end
wenzelm@12136
   647
  | unflat [] [] = []
skalberg@15570
   648
  | unflat _ _ = raise UnequalLengths;
wenzelm@12136
   649
haftmann@18441
   650
fun burrow f xss =
haftmann@18359
   651
  unflat xss ((f o flat) xss);
haftmann@18359
   652
haftmann@18549
   653
fun fold_burrow f xss s =
haftmann@18549
   654
  apfst (unflat xss) (f (flat xss) s);
haftmann@18359
   655
wenzelm@233
   656
(*like Lisp's MAPC -- seq proc [x1, ..., xn] evaluates
wenzelm@233
   657
  (proc x1; ...; proc xn) for side effects*)
skalberg@15570
   658
val seq = List.app;
wenzelm@233
   659
wenzelm@233
   660
(*separate s [x1, x2, ..., xn]  ===>  [x1, s, x2, s, ..., s, xn]*)
wenzelm@233
   661
fun separate s (x :: (xs as _ :: _)) = x :: s :: separate s xs
wenzelm@233
   662
  | separate _ xs = xs;
wenzelm@233
   663
wenzelm@233
   664
(*make the list [x, x, ..., x] of length n*)
wenzelm@233
   665
fun replicate n (x: 'a) : 'a list =
wenzelm@233
   666
  let fun rep (0, xs) = xs
wenzelm@233
   667
        | rep (n, xs) = rep (n - 1, x :: xs)
wenzelm@233
   668
  in
skalberg@15570
   669
    if n < 0 then raise Subscript
wenzelm@233
   670
    else rep (n, [])
wenzelm@233
   671
  end;
wenzelm@233
   672
wenzelm@14926
   673
fun translate_string f = String.translate (f o String.str);
wenzelm@14926
   674
wenzelm@4248
   675
(*multiply [a, b, c, ...] * [xs, ys, zs, ...]*)
wenzelm@18148
   676
fun multiply [] _ = []
wenzelm@18148
   677
  | multiply (x :: xs) yss = map (cons x) yss @ multiply xs yss;
wenzelm@4248
   678
wenzelm@14792
   679
(*direct product*)
wenzelm@14792
   680
fun product _ [] = []
wenzelm@14792
   681
  | product [] _ = []
wenzelm@14792
   682
  | product (x :: xs) ys = map (pair x) ys @ product xs ys;
wenzelm@14792
   683
wenzelm@233
   684
wenzelm@233
   685
(* filter *)
wenzelm@233
   686
wenzelm@233
   687
(*copy the list preserving elements that satisfy the predicate*)
skalberg@15531
   688
val filter = List.filter;
clasohm@0
   689
fun filter_out f = filter (not o f);
wenzelm@19483
   690
val map_filter = List.mapPartial;
wenzelm@233
   691
wenzelm@233
   692
wenzelm@233
   693
(* lists of pairs *)
wenzelm@233
   694
skalberg@15570
   695
exception UnequalLengths;
skalberg@15570
   696
haftmann@18330
   697
fun map2 _ [] [] = []
haftmann@18330
   698
  | map2 f (x :: xs) (y :: ys) = f x y :: map2 f xs ys
haftmann@18330
   699
  | map2 _ _ _ = raise UnequalLengths;
wenzelm@380
   700
haftmann@18330
   701
fun fold2 f =
haftmann@18330
   702
  let
haftmann@18330
   703
    fun fold_aux [] [] z = z
haftmann@18330
   704
      | fold_aux (x :: xs) (y :: ys) z = fold_aux xs ys (f x y z)
haftmann@18330
   705
      | fold_aux _ _ _ = raise UnequalLengths;
haftmann@18330
   706
  in fold_aux end;
wenzelm@380
   707
wenzelm@19799
   708
fun zip_options (x :: xs) (SOME y :: ys) = (x, y) :: zip_options xs ys
wenzelm@19799
   709
  | zip_options (_ :: xs) (NONE :: ys) = zip_options xs ys
wenzelm@19799
   710
  | zip_options _ [] = []
wenzelm@19799
   711
  | zip_options [] _ = raise UnequalLengths;
wenzelm@4956
   712
wenzelm@233
   713
(*combine two lists forming a list of pairs:
wenzelm@233
   714
  [x1, ..., xn] ~~ [y1, ..., yn]  ===>  [(x1, y1), ..., (xn, yn)]*)
wenzelm@233
   715
fun [] ~~ [] = []
wenzelm@233
   716
  | (x :: xs) ~~ (y :: ys) = (x, y) :: (xs ~~ ys)
skalberg@15570
   717
  | _ ~~ _ = raise UnequalLengths;
wenzelm@233
   718
wenzelm@233
   719
(*inverse of ~~; the old 'split':
wenzelm@233
   720
  [(x1, y1), ..., (xn, yn)]  ===>  ([x1, ..., xn], [y1, ..., yn])*)
skalberg@15570
   721
val split_list = ListPair.unzip;
wenzelm@233
   722
wenzelm@233
   723
wenzelm@233
   724
(* prefixes, suffixes *)
wenzelm@233
   725
haftmann@18441
   726
fun is_prefix _ [] _ = true
haftmann@18441
   727
  | is_prefix eq (x :: xs) (y :: ys) = eq (x, y) andalso is_prefix eq xs ys
haftmann@18441
   728
  | is_prefix eq _ _ = false;
wenzelm@233
   729
wenzelm@233
   730
(* [x1, ..., xi, ..., xn]  --->  ([x1, ..., x(i-1)], [xi, ..., xn])
wenzelm@233
   731
   where xi is the first element that does not satisfy the predicate*)
wenzelm@233
   732
fun take_prefix (pred : 'a -> bool)  (xs: 'a list) : 'a list * 'a list =
wenzelm@233
   733
  let fun take (rxs, []) = (rev rxs, [])
wenzelm@255
   734
        | take (rxs, x :: xs) =
wenzelm@255
   735
            if  pred x  then  take(x :: rxs, xs)  else  (rev rxs, x :: xs)
wenzelm@233
   736
  in  take([], xs)  end;
wenzelm@233
   737
haftmann@20108
   738
fun chop_prefix eq ([], ys) = ([], ([], ys))
haftmann@20108
   739
  | chop_prefix eq (xs, []) = ([], (xs, []))
haftmann@20108
   740
  | chop_prefix eq (xs as x::xs', ys as y::ys') =
haftmann@20108
   741
      if eq (x, y) then
haftmann@20108
   742
        let val (ps', xys'') = chop_prefix eq (xs', ys')
haftmann@20108
   743
        in (x::ps', xys'') end
haftmann@20108
   744
      else ([], (xs, ys));
haftmann@20108
   745
wenzelm@233
   746
(* [x1, ..., xi, ..., xn]  --->  ([x1, ..., xi], [x(i+1), ..., xn])
wenzelm@233
   747
   where xi is the last element that does not satisfy the predicate*)
wenzelm@233
   748
fun take_suffix _ [] = ([], [])
wenzelm@233
   749
  | take_suffix pred (x :: xs) =
wenzelm@233
   750
      (case take_suffix pred xs of
wenzelm@233
   751
        ([], sffx) => if pred x then ([], x :: sffx) else ([x], sffx)
wenzelm@233
   752
      | (prfx, sffx) => (x :: prfx, sffx));
wenzelm@233
   753
wenzelm@12249
   754
fun prefixes1 [] = []
wenzelm@12249
   755
  | prefixes1 (x :: xs) = map (cons x) ([] :: prefixes1 xs);
wenzelm@12249
   756
wenzelm@19011
   757
fun prefixes xs = [] :: prefixes1 xs;
wenzelm@19011
   758
wenzelm@12249
   759
fun suffixes1 xs = map rev (prefixes1 (rev xs));
wenzelm@19011
   760
fun suffixes xs = [] :: suffixes1 xs;
wenzelm@233
   761
wenzelm@233
   762
wenzelm@233
   763
(** integers **)
wenzelm@233
   764
wenzelm@16439
   765
fun gcd (x, y) =
paulson@15965
   766
  let fun gxd x y : IntInf.int =
nipkow@10692
   767
    if y = 0 then x else gxd y (x mod y)
nipkow@10692
   768
  in if x < y then gxd y x else gxd x y end;
nipkow@10692
   769
wenzelm@16439
   770
fun lcm (x, y) = (x * y) div gcd (x, y);
nipkow@10692
   771
wenzelm@2958
   772
fun inc i = (i := ! i + 1; ! i);
wenzelm@2958
   773
fun dec i = (i := ! i - 1; ! i);
wenzelm@233
   774
wenzelm@233
   775
wenzelm@233
   776
(* lists of integers *)
wenzelm@233
   777
wenzelm@233
   778
(*make the list [from, from + 1, ..., to]*)
paulson@2175
   779
fun (from upto to) =
wenzelm@233
   780
  if from > to then [] else from :: ((from + 1) upto to);
wenzelm@233
   781
wenzelm@233
   782
(*make the list [from, from - 1, ..., to]*)
paulson@2175
   783
fun (from downto to) =
wenzelm@233
   784
  if from < to then [] else from :: ((from - 1) downto to);
wenzelm@233
   785
wenzelm@233
   786
(*predicate: downto0 (is, n) <=> is = [n, n - 1, ..., 0]*)
wenzelm@233
   787
fun downto0 (i :: is, n) = i = n andalso downto0 (is, n - 1)
wenzelm@233
   788
  | downto0 ([], n) = n = ~1;
wenzelm@233
   789
wenzelm@233
   790
wenzelm@233
   791
(* convert integers to strings *)
wenzelm@233
   792
wenzelm@233
   793
(*expand the number in the given base;
wenzelm@233
   794
  example: radixpand (2, 8) gives [1, 0, 0, 0]*)
wenzelm@233
   795
fun radixpand (base, num) : int list =
wenzelm@233
   796
  let
wenzelm@233
   797
    fun radix (n, tail) =
wenzelm@233
   798
      if n < base then n :: tail
wenzelm@233
   799
      else radix (n div base, (n mod base) :: tail)
wenzelm@233
   800
  in radix (num, []) end;
wenzelm@233
   801
wenzelm@233
   802
(*expands a number into a string of characters starting from "zerochar";
wenzelm@233
   803
  example: radixstring (2, "0", 8) gives "1000"*)
wenzelm@233
   804
fun radixstring (base, zerochar, num) =
wenzelm@233
   805
  let val offset = ord zerochar;
wenzelm@233
   806
      fun chrof n = chr (offset + n)
wenzelm@233
   807
  in implode (map chrof (radixpand (base, num))) end;
wenzelm@233
   808
wenzelm@233
   809
paulson@3407
   810
val string_of_int = Int.toString;
wenzelm@233
   811
paulson@3407
   812
fun string_of_indexname (a,0) = a
paulson@3407
   813
  | string_of_indexname (a,i) = a ^ "_" ^ Int.toString i;
wenzelm@233
   814
wenzelm@233
   815
wenzelm@14826
   816
(* read integers *)
wenzelm@14826
   817
wenzelm@20095
   818
fun read_intinf radix cs =
wenzelm@20095
   819
  let
wenzelm@20095
   820
    val zero = ord "0";
wenzelm@20095
   821
    val limit = zero + radix;
wenzelm@20095
   822
    fun scan (num, []) = (num, [])
wenzelm@20095
   823
      | scan (num, c :: cs) =
wenzelm@20095
   824
        if zero <= ord c andalso ord c < limit then
wenzelm@20095
   825
          scan (IntInf.fromInt radix * num + IntInf.fromInt (ord c - zero), cs)
wenzelm@20095
   826
        else (num, c :: cs);
wenzelm@20095
   827
  in scan (0, cs) end;
wenzelm@14826
   828
wenzelm@20095
   829
fun read_int cs = apfst IntInf.toInt (read_intinf 10 cs);
wenzelm@14826
   830
wenzelm@20095
   831
fun oct_char s = chr (IntInf.toInt (#1 (read_intinf 8 (explode s))));
wenzelm@14826
   832
wenzelm@14826
   833
wenzelm@14826
   834
wenzelm@233
   835
(** strings **)
wenzelm@233
   836
wenzelm@16188
   837
(* functions tuned for strings, avoiding explode *)
wenzelm@6312
   838
haftmann@18011
   839
fun nth_string str i =
wenzelm@6959
   840
  (case try String.substring (str, i, 1) of
skalberg@15531
   841
    SOME s => s
skalberg@15570
   842
  | NONE => raise Subscript);
wenzelm@6312
   843
wenzelm@16188
   844
fun fold_string f str x0 =
wenzelm@6282
   845
  let
wenzelm@6282
   846
    val n = size str;
wenzelm@16188
   847
    fun iter (x, i) =
wenzelm@16188
   848
      if i < n then iter (f (String.substring (str, i, 1)) x, i + 1) else x;
wenzelm@16188
   849
  in iter (x0, 0) end;
wenzelm@6282
   850
wenzelm@14968
   851
fun exists_string pred str =
wenzelm@14968
   852
  let
wenzelm@14968
   853
    val n = size str;
wenzelm@14968
   854
    fun ex i = i < n andalso (pred (String.substring (str, i, 1)) orelse ex (i + 1));
wenzelm@14968
   855
  in ex 0 end;
wenzelm@6312
   856
wenzelm@16188
   857
fun forall_string pred = not o exists_string (not o pred);
wenzelm@16188
   858
lcp@512
   859
(*enclose in brackets*)
lcp@512
   860
fun enclose lpar rpar str = lpar ^ str ^ rpar;
wenzelm@6642
   861
fun unenclose str = String.substring (str, 1, size str - 2);
wenzelm@255
   862
wenzelm@233
   863
(*simple quoting (does not escape special chars)*)
lcp@512
   864
val quote = enclose "\"" "\"";
wenzelm@233
   865
wenzelm@4212
   866
(*space_implode "..." (explode "hello") = "h...e...l...l...o"*)
wenzelm@233
   867
fun space_implode a bs = implode (separate a bs);
wenzelm@233
   868
wenzelm@255
   869
val commas = space_implode ", ";
wenzelm@380
   870
val commas_quote = commas o map quote;
wenzelm@255
   871
wenzelm@233
   872
(*concatenate messages, one per line, into a string*)
wenzelm@255
   873
val cat_lines = space_implode "\n";
wenzelm@233
   874
wenzelm@4212
   875
(*space_explode "." "h.e..l.lo" = ["h", "e", "", "l", "lo"]*)
wenzelm@3832
   876
fun space_explode _ "" = []
wenzelm@3832
   877
  | space_explode sep str =
wenzelm@3832
   878
      let
wenzelm@3832
   879
        fun expl chs =
wenzelm@19301
   880
          (case take_prefix (fn s => s <> sep) chs of
wenzelm@3832
   881
            (cs, []) => [implode cs]
wenzelm@3832
   882
          | (cs, _ :: cs') => implode cs :: expl cs');
wenzelm@3832
   883
      in expl (explode str) end;
wenzelm@3832
   884
wenzelm@3832
   885
val split_lines = space_explode "\n";
wenzelm@3832
   886
wenzelm@14826
   887
fun prefix_lines "" txt = txt
wenzelm@14826
   888
  | prefix_lines prfx txt = txt |> split_lines |> map (fn s => prfx ^ s) |> cat_lines;
wenzelm@14826
   889
wenzelm@7712
   890
fun untabify chs =
wenzelm@7712
   891
  let
wenzelm@7712
   892
    val tab_width = 8;
wenzelm@7712
   893
wenzelm@7712
   894
    fun untab (_, "\n") = (0, ["\n"])
wenzelm@9118
   895
      | untab (pos, "\t") =
wenzelm@9118
   896
          let val d = tab_width - (pos mod tab_width) in (pos + d, replicate d " ") end
wenzelm@7712
   897
      | untab (pos, c) = (pos + 1, [c]);
wenzelm@7712
   898
  in
wenzelm@19301
   899
    if not (exists (fn c => c = "\t") chs) then chs
wenzelm@7712
   900
    else flat (#2 (foldl_map untab (0, chs)))
wenzelm@7712
   901
  end;
wenzelm@7712
   902
wenzelm@18681
   903
fun prefix prfx s = prfx ^ s;
wenzelm@16188
   904
fun suffix sffx s = s ^ sffx;
wenzelm@5285
   905
wenzelm@18681
   906
fun unprefix prfx s =
wenzelm@18681
   907
  if String.isPrefix prfx s then String.substring (s, size prfx, size s - size prfx)
wenzelm@18681
   908
  else raise Fail "unprefix";
wenzelm@18681
   909
wenzelm@16188
   910
fun unsuffix sffx s =
wenzelm@17061
   911
  if String.isSuffix sffx s then String.substring (s, 0, size s - size sffx)
wenzelm@17061
   912
  else raise Fail "unsuffix";
wenzelm@5285
   913
wenzelm@10951
   914
fun replicate_string 0 _ = ""
wenzelm@10951
   915
  | replicate_string 1 a = a
wenzelm@10951
   916
  | replicate_string k a =
wenzelm@10951
   917
      if k mod 2 = 0 then replicate_string (k div 2) (a ^ a)
wenzelm@10951
   918
      else replicate_string (k div 2) (a ^ a) ^ a;
wenzelm@10951
   919
wenzelm@19644
   920
fun string_of_list f = enclose "[" "]" o commas o map f;
wenzelm@19644
   921
wenzelm@19644
   922
fun string_of_option f NONE = "NONE"
wenzelm@19644
   923
  | string_of_option f (SOME x) = "SOME (" ^ f x ^ ")";
wenzelm@19644
   924
wenzelm@3832
   925
wenzelm@233
   926
wenzelm@16492
   927
(** lists as sets -- see also Pure/General/ord_list.ML **)
wenzelm@233
   928
wenzelm@18923
   929
(*canonical member, insert, remove*)
wenzelm@18923
   930
fun member eq list x =
wenzelm@18923
   931
  let
wenzelm@18923
   932
    fun memb [] = false
wenzelm@18923
   933
      | memb (y :: ys) = eq (x, y) orelse memb ys;
wenzelm@18923
   934
  in memb list end;
berghofe@1576
   935
wenzelm@18923
   936
fun insert eq x xs = if member eq xs x then xs else x :: xs;
wenzelm@18923
   937
fun remove eq x xs = if member eq xs x then filter_out (fn y => eq (x, y)) xs else xs;
wenzelm@233
   938
wenzelm@19301
   939
fun subtract eq = fold (remove eq);
wenzelm@19301
   940
wenzelm@18923
   941
fun merge _ ([], ys) = ys
wenzelm@18923
   942
  | merge eq (xs, ys) = fold_rev (insert eq) ys xs;
clasohm@0
   943
wenzelm@18923
   944
(*old-style infixes*)
wenzelm@18923
   945
fun x mem xs = member (op =) xs x;
wenzelm@18923
   946
fun (x: int) mem_int xs = member (op =) xs x;
wenzelm@18923
   947
fun (x: string) mem_string xs = member (op =) xs x;
berghofe@1576
   948
wenzelm@233
   949
wenzelm@233
   950
(*union of sets represented as lists: no repetitions*)
wenzelm@233
   951
fun xs union [] = xs
wenzelm@233
   952
  | [] union ys = ys
haftmann@20854
   953
  | (x :: xs) union ys = xs union (insert (op =) x ys);
clasohm@0
   954
paulson@2175
   955
(*union of sets, optimized version for ints*)
berghofe@1576
   956
fun (xs:int list) union_int [] = xs
berghofe@1576
   957
  | [] union_int ys = ys
haftmann@20854
   958
  | (x :: xs) union_int ys = xs union_int (insert (op =) x ys);
berghofe@1576
   959
paulson@2175
   960
(*union of sets, optimized version for strings*)
berghofe@1576
   961
fun (xs:string list) union_string [] = xs
berghofe@1576
   962
  | [] union_string ys = ys
haftmann@20854
   963
  | (x :: xs) union_string ys = xs union_string (insert (op =) x ys);
berghofe@1576
   964
clasohm@0
   965
(*generalized union*)
wenzelm@233
   966
fun gen_union eq (xs, []) = xs
wenzelm@233
   967
  | gen_union eq ([], ys) = ys
wenzelm@18923
   968
  | gen_union eq (x :: xs, ys) = gen_union eq (xs, insert eq x ys);
wenzelm@233
   969
wenzelm@233
   970
wenzelm@233
   971
(*intersection*)
wenzelm@233
   972
fun [] inter ys = []
wenzelm@233
   973
  | (x :: xs) inter ys =
wenzelm@233
   974
      if x mem ys then x :: (xs inter ys) else xs inter ys;
wenzelm@233
   975
paulson@2175
   976
(*intersection, optimized version for ints*)
berghofe@1576
   977
fun ([]:int list) inter_int ys = []
berghofe@1576
   978
  | (x :: xs) inter_int ys =
berghofe@1576
   979
      if x mem_int ys then x :: (xs inter_int ys) else xs inter_int ys;
berghofe@1576
   980
paulson@2175
   981
(*intersection, optimized version for strings *)
berghofe@1576
   982
fun ([]:string list) inter_string ys = []
berghofe@1576
   983
  | (x :: xs) inter_string ys =
berghofe@1576
   984
      if x mem_string ys then x :: (xs inter_string ys) else xs inter_string ys;
berghofe@1576
   985
paulson@7090
   986
(*generalized intersection*)
paulson@7090
   987
fun gen_inter eq ([], ys) = []
wenzelm@12284
   988
  | gen_inter eq (x::xs, ys) =
wenzelm@18923
   989
      if member eq ys x then x :: gen_inter eq (xs, ys)
wenzelm@18923
   990
      else gen_inter eq (xs, ys);
paulson@7090
   991
wenzelm@233
   992
wenzelm@233
   993
(*subset*)
wenzelm@233
   994
fun [] subset ys = true
wenzelm@233
   995
  | (x :: xs) subset ys = x mem ys andalso xs subset ys;
wenzelm@233
   996
paulson@2175
   997
(*subset, optimized version for ints*)
wenzelm@16439
   998
fun ([]: int list) subset_int ys = true
berghofe@1576
   999
  | (x :: xs) subset_int ys = x mem_int ys andalso xs subset_int ys;
berghofe@1576
  1000
paulson@2175
  1001
(*subset, optimized version for strings*)
wenzelm@16439
  1002
fun ([]: string list) subset_string ys = true
berghofe@1576
  1003
  | (x :: xs) subset_string ys = x mem_string ys andalso xs subset_string ys;
berghofe@1576
  1004
wenzelm@4363
  1005
(*set equality*)
wenzelm@4363
  1006
fun eq_set (xs, ys) =
wenzelm@4363
  1007
  xs = ys orelse (xs subset ys andalso ys subset xs);
wenzelm@4363
  1008
paulson@2182
  1009
(*set equality for strings*)
wenzelm@16439
  1010
fun eq_set_string ((xs: string list), ys) =
berghofe@1576
  1011
  xs = ys orelse (xs subset_string ys andalso ys subset_string xs);
berghofe@1576
  1012
wenzelm@18923
  1013
fun gen_subset eq (xs, ys) = forall (member eq ys) xs;
paulson@2182
  1014
wenzelm@19301
  1015
fun gen_eq_set eq (xs, ys) =
haftmann@20348
  1016
  eq_list eq (xs, ys) orelse
wenzelm@19301
  1017
    (gen_subset eq (xs, ys) andalso gen_subset (eq o swap) (ys, xs));
wenzelm@19301
  1018
wenzelm@265
  1019
wenzelm@233
  1020
(*removing an element from a list WITHOUT duplicates*)
wenzelm@233
  1021
fun (y :: ys) \ x = if x = y then ys else y :: (ys \ x)
wenzelm@233
  1022
  | [] \ x = [];
paulson@2243
  1023
fun ys \\ xs = foldl (op \) (ys,xs);
clasohm@0
  1024
wenzelm@233
  1025
wenzelm@233
  1026
(*makes a list of the distinct members of the input; preserves order, takes
wenzelm@233
  1027
  first of equal elements*)
wenzelm@19046
  1028
fun distinct eq lst =
wenzelm@233
  1029
  let
wenzelm@233
  1030
    fun dist (rev_seen, []) = rev rev_seen
wenzelm@233
  1031
      | dist (rev_seen, x :: xs) =
wenzelm@18923
  1032
          if member eq rev_seen x then dist (rev_seen, xs)
wenzelm@233
  1033
          else dist (x :: rev_seen, xs);
wenzelm@19046
  1034
  in dist ([], lst) end;
wenzelm@233
  1035
wenzelm@255
  1036
(*returns a list containing all repeated elements exactly once; preserves
wenzelm@255
  1037
  order, takes first of equal elements*)
wenzelm@18966
  1038
fun duplicates eq lst =
wenzelm@255
  1039
  let
wenzelm@255
  1040
    fun dups (rev_dups, []) = rev rev_dups
wenzelm@255
  1041
      | dups (rev_dups, x :: xs) =
wenzelm@18923
  1042
          if member eq rev_dups x orelse not (member eq xs x) then
wenzelm@255
  1043
            dups (rev_dups, xs)
wenzelm@255
  1044
          else dups (x :: rev_dups, xs);
wenzelm@18966
  1045
  in dups ([], lst) end;
wenzelm@255
  1046
wenzelm@16878
  1047
fun has_duplicates eq =
wenzelm@16878
  1048
  let
wenzelm@16878
  1049
    fun dups [] = false
wenzelm@16878
  1050
      | dups (x :: xs) = member eq xs x orelse dups xs;
wenzelm@16878
  1051
  in dups end;
wenzelm@16878
  1052
wenzelm@255
  1053
haftmann@19119
  1054
(** association lists -- legacy operations **)
wenzelm@233
  1055
wenzelm@12284
  1056
fun gen_merge_lists _ xs [] = xs
wenzelm@12284
  1057
  | gen_merge_lists _ [] ys = ys
haftmann@20951
  1058
  | gen_merge_lists eq xs ys = xs @ filter_out (member eq xs) ys;
clasohm@0
  1059
wenzelm@12284
  1060
fun merge_lists xs ys = gen_merge_lists (op =) xs ys;
haftmann@20951
  1061
fun merge_alists xs = gen_merge_lists (eq_fst (op =)) xs;
clasohm@0
  1062
clasohm@0
  1063
wenzelm@233
  1064
(** balanced trees **)
wenzelm@233
  1065
wenzelm@233
  1066
exception Balance;      (*indicates non-positive argument to balancing fun*)
wenzelm@233
  1067
wenzelm@233
  1068
(*balanced folding; avoids deep nesting*)
wenzelm@233
  1069
fun fold_bal f [x] = x
wenzelm@233
  1070
  | fold_bal f [] = raise Balance
wenzelm@233
  1071
  | fold_bal f xs =
wenzelm@19474
  1072
      let val (ps, qs) = chop (length xs div 2) xs
nipkow@13629
  1073
      in  f (fold_bal f ps, fold_bal f qs)  end;
wenzelm@233
  1074
wenzelm@233
  1075
(*construct something of the form f(...g(...(x)...)) for balanced access*)
wenzelm@233
  1076
fun access_bal (f, g, x) n i =
wenzelm@233
  1077
  let fun acc n i =     (*1<=i<=n*)
wenzelm@233
  1078
          if n=1 then x else
wenzelm@233
  1079
          let val n2 = n div 2
wenzelm@233
  1080
          in  if i<=n2 then f (acc n2 i)
wenzelm@233
  1081
                       else g (acc (n-n2) (i-n2))
wenzelm@233
  1082
          end
wenzelm@233
  1083
  in  if 1<=i andalso i<=n then acc n i else raise Balance  end;
wenzelm@233
  1084
wenzelm@233
  1085
(*construct ALL such accesses; could try harder to share recursive calls!*)
wenzelm@233
  1086
fun accesses_bal (f, g, x) n =
wenzelm@233
  1087
  let fun acc n =
wenzelm@233
  1088
          if n=1 then [x] else
wenzelm@233
  1089
          let val n2 = n div 2
wenzelm@233
  1090
              val acc2 = acc n2
wenzelm@233
  1091
          in  if n-n2=n2 then map f acc2 @ map g acc2
wenzelm@233
  1092
                         else map f acc2 @ map g (acc (n-n2)) end
wenzelm@233
  1093
  in  if 1<=n then acc n else raise Balance  end;
wenzelm@233
  1094
wenzelm@233
  1095
wenzelm@233
  1096
wenzelm@2506
  1097
(** orders **)
wenzelm@2506
  1098
wenzelm@18966
  1099
fun is_equal EQUAL = true
wenzelm@18966
  1100
  | is_equal _ = false;
wenzelm@18966
  1101
wenzelm@4445
  1102
fun rev_order LESS = GREATER
wenzelm@4445
  1103
  | rev_order EQUAL = EQUAL
wenzelm@4445
  1104
  | rev_order GREATER = LESS;
wenzelm@4445
  1105
wenzelm@4479
  1106
(*assume rel is a linear strict order*)
wenzelm@4445
  1107
fun make_ord rel (x, y) =
wenzelm@4445
  1108
  if rel (x, y) then LESS
wenzelm@4445
  1109
  else if rel (y, x) then GREATER
wenzelm@4445
  1110
  else EQUAL;
wenzelm@4445
  1111
wenzelm@15051
  1112
val int_ord = Int.compare;
wenzelm@15051
  1113
val string_ord = String.compare;
wenzelm@2506
  1114
wenzelm@16676
  1115
fun fast_string_ord (s1, s2) =
wenzelm@16676
  1116
  (case int_ord (size s1, size s2) of EQUAL => string_ord (s1, s2) | ord => ord);
wenzelm@16676
  1117
wenzelm@16492
  1118
fun option_ord ord (SOME x, SOME y) = ord (x, y)
wenzelm@16492
  1119
  | option_ord _ (NONE, NONE) = EQUAL
wenzelm@16492
  1120
  | option_ord _ (NONE, SOME _) = LESS
wenzelm@16492
  1121
  | option_ord _ (SOME _, NONE) = GREATER;
wenzelm@16492
  1122
wenzelm@4343
  1123
(*lexicographic product*)
wenzelm@4343
  1124
fun prod_ord a_ord b_ord ((x, y), (x', y')) =
wenzelm@4343
  1125
  (case a_ord (x, x') of EQUAL => b_ord (y, y') | ord => ord);
wenzelm@4343
  1126
wenzelm@4343
  1127
(*dictionary order -- in general NOT well-founded!*)
wenzelm@16984
  1128
fun dict_ord elem_ord (x :: xs, y :: ys) =
wenzelm@16984
  1129
      (case elem_ord (x, y) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord)
wenzelm@16984
  1130
  | dict_ord _ ([], []) = EQUAL
wenzelm@4343
  1131
  | dict_ord _ ([], _ :: _) = LESS
wenzelm@16984
  1132
  | dict_ord _ (_ :: _, []) = GREATER;
wenzelm@4343
  1133
wenzelm@4343
  1134
(*lexicographic product of lists*)
wenzelm@4343
  1135
fun list_ord elem_ord (xs, ys) =
wenzelm@16676
  1136
  (case int_ord (length xs, length ys) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord);
wenzelm@4343
  1137
wenzelm@2506
  1138
wenzelm@4621
  1139
(* sorting *)
wenzelm@4621
  1140
wenzelm@18427
  1141
(*quicksort -- stable, i.e. does not reorder equal elements*)
wenzelm@18427
  1142
fun quicksort unique ord =
wenzelm@4621
  1143
  let
wenzelm@16878
  1144
    fun qsort [] = []
wenzelm@16878
  1145
      | qsort (xs as [_]) = xs
wenzelm@18427
  1146
      | qsort (xs as [x, y]) =
wenzelm@18427
  1147
          (case ord (x, y) of
wenzelm@18427
  1148
            LESS => xs
wenzelm@18427
  1149
          | EQUAL => if unique then [x] else xs
wenzelm@18427
  1150
          | GREATER => [y, x])
wenzelm@16878
  1151
      | qsort xs =
haftmann@18011
  1152
          let val (lts, eqs, gts) = part (nth xs (length xs div 2)) xs
wenzelm@16878
  1153
          in qsort lts @ eqs @ qsort gts end
wenzelm@4621
  1154
    and part _ [] = ([], [], [])
wenzelm@4621
  1155
      | part pivot (x :: xs) = add (ord (x, pivot)) x (part pivot xs)
wenzelm@4621
  1156
    and add LESS x (lts, eqs, gts) = (x :: lts, eqs, gts)
wenzelm@18427
  1157
      | add EQUAL x (lts, [], gts) = (lts, [x], gts)
wenzelm@18427
  1158
      | add EQUAL x (res as (lts, eqs, gts)) = if unique then res else (lts, x :: eqs, gts)
wenzelm@4621
  1159
      | add GREATER x (lts, eqs, gts) = (lts, eqs, x :: gts);
wenzelm@4621
  1160
  in qsort end;
wenzelm@4621
  1161
wenzelm@18427
  1162
fun sort ord = quicksort false ord;
wenzelm@18427
  1163
fun sort_distinct ord = quicksort true ord;
wenzelm@18427
  1164
wenzelm@4621
  1165
val sort_strings = sort string_ord;
wenzelm@4621
  1166
fun sort_wrt sel xs = sort (string_ord o pairself sel) xs;
wenzelm@4621
  1167
wenzelm@4621
  1168
wenzelm@2506
  1169
berghofe@14106
  1170
(** random numbers **)
berghofe@14106
  1171
berghofe@14106
  1172
exception RANDOM;
berghofe@14106
  1173
berghofe@14618
  1174
fun rmod x y = x - y * Real.realFloor (x / y);
berghofe@14106
  1175
berghofe@14106
  1176
local
berghofe@14106
  1177
  val a = 16807.0;
berghofe@14106
  1178
  val m = 2147483647.0;
berghofe@14106
  1179
  val random_seed = ref 1.0;
berghofe@14106
  1180
in
berghofe@14106
  1181
berghofe@14106
  1182
fun random () =
berghofe@14106
  1183
  let val r = rmod (a * !random_seed) m
berghofe@14106
  1184
  in (random_seed := r; r) end;
berghofe@14106
  1185
berghofe@14106
  1186
end;
berghofe@14106
  1187
berghofe@14106
  1188
fun random_range l h =
berghofe@14106
  1189
  if h < l orelse l < 0 then raise RANDOM
berghofe@14106
  1190
  else l + Real.floor (rmod (random ()) (real (h - l + 1)));
berghofe@14106
  1191
haftmann@18011
  1192
fun one_of xs = nth xs (random_range 0 (length xs - 1));
berghofe@14106
  1193
berghofe@14106
  1194
fun frequency xs =
berghofe@14106
  1195
  let
berghofe@14106
  1196
    val sum = foldl op + (0, map fst xs);
wenzelm@17756
  1197
    fun pick n ((k: int, x) :: xs) =
berghofe@14106
  1198
      if n <= k then x else pick (n - k) xs
berghofe@14106
  1199
  in pick (random_range 1 sum) xs end;
berghofe@14106
  1200
berghofe@14106
  1201
wenzelm@14826
  1202
(** current directory **)
wenzelm@233
  1203
paulson@2243
  1204
val cd = OS.FileSys.chDir;
wenzelm@2317
  1205
val pwd = OS.FileSys.getDir;
paulson@2243
  1206
berghofe@3606
  1207
wenzelm@19644
  1208
wenzelm@4621
  1209
(** misc **)
wenzelm@233
  1210
wenzelm@19644
  1211
fun divide_and_conquer decomp x =
wenzelm@19644
  1212
  let val (ys, recomb) = decomp x
wenzelm@19644
  1213
  in recomb (map (divide_and_conquer decomp) ys) end;
wenzelm@19644
  1214
clasohm@0
  1215
wenzelm@233
  1216
(*Partition a list into buckets  [ bi, b(i+1), ..., bj ]
clasohm@0
  1217
   putting x in bk if p(k)(x) holds.  Preserve order of elements if possible.*)
clasohm@0
  1218
fun partition_list p i j =
wenzelm@233
  1219
  let fun part k xs =
wenzelm@233
  1220
            if k>j then
clasohm@0
  1221
              (case xs of [] => []
skalberg@15570
  1222
                         | _ => raise Fail "partition_list")
clasohm@0
  1223
            else
wenzelm@19691
  1224
            let val (ns, rest) = List.partition (p k) xs;
wenzelm@233
  1225
            in  ns :: part(k+1)rest  end
clasohm@0
  1226
  in  part i end;
clasohm@0
  1227
wenzelm@19691
  1228
fun partition_eq (eq:'a * 'a -> bool) =
wenzelm@19691
  1229
  let
wenzelm@19691
  1230
    fun part [] = []
wenzelm@19691
  1231
      | part (x :: ys) =
wenzelm@19691
  1232
          let val (xs, xs') = List.partition (fn y => eq (x, y)) ys
wenzelm@19691
  1233
          in (x::xs)::(part xs') end
wenzelm@19691
  1234
  in part end;
wenzelm@19691
  1235
wenzelm@19691
  1236
clasohm@0
  1237
wenzelm@233
  1238
(* generating identifiers *)
clasohm@0
  1239
paulson@4063
  1240
(** Freshly generated identifiers; supplied prefix MUST start with a letter **)
clasohm@0
  1241
local
paulson@4063
  1242
(*Maps 0-63 to A-Z, a-z, 0-9 or _ or ' for generating random identifiers*)
paulson@4063
  1243
fun char i =      if i<26 then chr (ord "A" + i)
wenzelm@5904
  1244
             else if i<52 then chr (ord "a" + i - 26)
wenzelm@5904
  1245
             else if i<62 then chr (ord"0" + i - 52)
wenzelm@5904
  1246
             else if i=62 then "_"
wenzelm@5904
  1247
             else  (*i=63*)    "'";
paulson@4063
  1248
paulson@4063
  1249
val charVec = Vector.tabulate (64, char);
paulson@4063
  1250
wenzelm@5904
  1251
fun newid n =
wenzelm@5904
  1252
  let
wenzelm@4284
  1253
  in  implode (map (fn i => Vector.sub(charVec,i)) (radixpand (64,n)))  end;
paulson@2003
  1254
wenzelm@4284
  1255
val seedr = ref 0;
clasohm@0
  1256
paulson@4063
  1257
in
wenzelm@4284
  1258
wenzelm@12346
  1259
fun gensym pre = pre ^ (#1(newid (!seedr), inc seedr));
paulson@2003
  1260
paulson@4063
  1261
end;
paulson@4063
  1262
paulson@4063
  1263
wenzelm@233
  1264
(* lexical scanning *)
clasohm@0
  1265
wenzelm@233
  1266
(*scan a list of characters into "words" composed of "letters" (recognized by
wenzelm@233
  1267
  is_let) and separated by any number of non-"letters"*)
wenzelm@233
  1268
fun scanwords is_let cs =
clasohm@0
  1269
  let fun scan1 [] = []
wenzelm@233
  1270
        | scan1 cs =
wenzelm@233
  1271
            let val (lets, rest) = take_prefix is_let cs
wenzelm@233
  1272
            in implode lets :: scanwords is_let rest end;
wenzelm@233
  1273
  in scan1 (#2 (take_prefix (not o is_let) cs)) end;
clasohm@24
  1274
wenzelm@4212
  1275
wenzelm@16439
  1276
(* stamps and serial numbers *)
wenzelm@16439
  1277
wenzelm@16439
  1278
type stamp = unit ref;
wenzelm@16439
  1279
val stamp: unit -> stamp = ref;
wenzelm@16439
  1280
wenzelm@16439
  1281
type serial = int;
wenzelm@16439
  1282
local val count = ref 0
wenzelm@16439
  1283
in fun serial () = inc count end;
wenzelm@16439
  1284
wenzelm@19512
  1285
val serial_string = string_of_int o serial;
wenzelm@19512
  1286
wenzelm@16535
  1287
wenzelm@16535
  1288
(* generic objects *)
wenzelm@16535
  1289
wenzelm@16535
  1290
(*note that the builtin exception datatype may be extended by new
wenzelm@16535
  1291
  constructors at any time*)
wenzelm@16535
  1292
structure Object = struct type T = exn end;
wenzelm@16535
  1293
clasohm@1364
  1294
end;
clasohm@1364
  1295
wenzelm@15745
  1296
structure BasicLibrary: BASIC_LIBRARY = Library;
wenzelm@15745
  1297
open BasicLibrary;