src/Pure/library.ML
author wenzelm
Sat Jan 14 17:14:14 2006 +0100 (2006-01-14)
changeset 18681 3020496cff28
parent 18549 5308a6ea3b96
child 18712 836520885b8f
permissions -rw-r--r--
added exception ERROR, error, cat_error, sys_error, assert, deny, assert_all;
added transform_failure;
added prefix;
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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, association lists, generic
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tables, 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 \ \\ ins ins_string ins_int 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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  (*old options -- invalidated*)
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  datatype invalid = None of invalid
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  exception OPTION of invalid
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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 if_none: 'a option -> 'a -> 'a
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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 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 sys_error: 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 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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  (*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 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 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 splitAt: 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_update: int * 'a -> 'a list -> 'a list
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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_first: ('a -> 'b option) -> 'a list -> 'b option
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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 ~~ : '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 equal_lists: ('a * 'b -> bool) -> 'a list * 'b list -> bool
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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 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 suffixes1: '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_radixint: int * string list -> 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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  (*lists as sets -- see also Pure/General/ord_list.ML*)
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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 gen_mem: ('a * 'b -> bool) -> 'a * 'b list -> bool
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  val ins: ''a * ''a list -> ''a list
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  val ins_int: int * int list -> int list
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  val ins_string: string * string list -> string list
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  val gen_ins: ('a * 'a -> bool) -> 'a * 'a list -> 'a list
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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 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 \ : ''a list * ''a -> ''a list
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  val \\ : ''a list * ''a list -> ''a list
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  val gen_rem: ('a * 'b -> bool) -> 'a list * 'b -> 'a list
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  val gen_rems: ('a * 'b -> bool) -> 'a list * 'b list -> 'a list
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  val gen_distinct: ('a * 'a -> bool) -> 'a list -> 'a list
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  val distinct: ''a list -> ''a list
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  val findrep: ''a list -> ''a list
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  val gen_duplicates: ('a * 'a -> bool) -> 'a list -> 'a list
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  val duplicates: ''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 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_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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  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 rev_order: order -> order
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  val make_ord: ('a * 'a -> bool) -> 'a * 'a -> order
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  val eq_ord: ('a -> order) -> 'a -> bool
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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 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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  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
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  val last_elem: 'a list -> 'a
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  val flat: 'a list list -> 'a list
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  val seq: ('a -> unit) -> 'a list -> unit
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  val partition: ('a -> bool) -> 'a list -> 'a list * 'a list
skalberg@15570
   286
  val mapfilter: ('a -> 'b option) -> 'a list -> 'b list
skalberg@15570
   287
end;
skalberg@15570
   288
wenzelm@15745
   289
structure Library: LIBRARY =
clasohm@1364
   290
struct
clasohm@0
   291
wenzelm@4995
   292
wenzelm@233
   293
(** functions **)
clasohm@0
   294
wenzelm@16842
   295
fun I x = x;
wenzelm@16842
   296
fun K x = fn _ => x;
wenzelm@233
   297
fun curry f x y = f (x, y);
wenzelm@233
   298
fun uncurry f (x, y) = f x y;
clasohm@0
   299
wenzelm@16705
   300
(*reverse application and structured results*)
wenzelm@16705
   301
fun x |> f = f x;
wenzelm@16705
   302
fun (x, y) |-> f = f x y;
wenzelm@16705
   303
fun (x, y) |>> f = (f x, y);
wenzelm@16705
   304
fun (x, y) ||> f = (x, f y);
wenzelm@16705
   305
fun (x, y) |>>> f = let val (x', z) = f x in (x', (y, z)) end;
wenzelm@16705
   306
fun (x, y) ||>> f = let val (z, y') = f y in ((x, z), y') end;
wenzelm@16842
   307
wenzelm@16842
   308
(*reverse composition*)
haftmann@16780
   309
fun f #> g = g o f;
wenzelm@16842
   310
fun f #-> g = uncurry g o f;
wenzelm@16842
   311
haftmann@17141
   312
(*conditional application*)
wenzelm@17545
   313
fun b ? f = fn x => if b x then f x else x;
haftmann@17141
   314
wenzelm@16842
   315
(*view results*)
wenzelm@16842
   316
fun `f = fn x => (f x, x);
wenzelm@17545
   317
fun tap f = fn x => (f x; x);
wenzelm@380
   318
wenzelm@16721
   319
(*composition with multiple args*)
wenzelm@16721
   320
fun (f oo g) x y = f (g x y);
wenzelm@16721
   321
fun (f ooo g) x y z = f (g x y z);
wenzelm@16721
   322
fun (f oooo g) x y z w = f (g x y z w);
wenzelm@16721
   323
wenzelm@233
   324
(*function exponentiation: f(...(f x)...) with n applications of f*)
wenzelm@233
   325
fun funpow n f x =
wenzelm@233
   326
  let fun rep (0, x) = x
wenzelm@233
   327
        | rep (n, x) = rep (n - 1, f x)
wenzelm@233
   328
  in rep (n, x) end;
wenzelm@160
   329
wenzelm@160
   330
wenzelm@233
   331
(** options **)
clasohm@0
   332
wenzelm@15670
   333
(*invalidate former constructors to prevent accidental use as match-all patterns!*)
wenzelm@15670
   334
datatype invalid = None of invalid;
wenzelm@15670
   335
exception OPTION of invalid;
clasohm@0
   336
wenzelm@15970
   337
val the = Option.valOf;
wenzelm@17341
   338
haftmann@17153
   339
fun these (SOME x) = x
haftmann@17313
   340
  | these _ = [];
wenzelm@17341
   341
haftmann@17313
   342
fun the_default x (SOME y) = y
haftmann@17313
   343
  | the_default x _ = x;
wenzelm@17341
   344
haftmann@17313
   345
fun the_list (SOME x) = [x]
haftmann@17313
   346
  | the_list _ = []
wenzelm@15970
   347
wenzelm@15970
   348
(*strict!*)
wenzelm@15970
   349
fun if_none NONE y = y
wenzelm@15970
   350
  | if_none (SOME x) _ = x;
wenzelm@15970
   351
wenzelm@15970
   352
fun is_some (SOME _) = true
wenzelm@15970
   353
  | is_some NONE = false;
wenzelm@15970
   354
wenzelm@15970
   355
fun is_none (SOME _) = false
wenzelm@15970
   356
  | is_none NONE = true;
wenzelm@15970
   357
wenzelm@18376
   358
fun perhaps f x = the_default x (f x);
wenzelm@18376
   359
wenzelm@6959
   360
wenzelm@17341
   361
(* exceptions *)
wenzelm@17341
   362
wenzelm@18681
   363
val do_transform_failure = ref true;
wenzelm@18681
   364
wenzelm@18681
   365
fun transform_failure exn f x =
wenzelm@18681
   366
  if ! do_transform_failure then
wenzelm@18681
   367
    f x handle Interrupt => raise Interrupt | e => raise exn e
wenzelm@18681
   368
  else f x;
wenzelm@18681
   369
wenzelm@17341
   370
exception EXCEPTION of exn * string;
wenzelm@6959
   371
wenzelm@6959
   372
skalberg@15531
   373
fun try f x = SOME (f x)
wenzelm@18681
   374
  handle Interrupt => raise Interrupt | _ => NONE;
wenzelm@6959
   375
wenzelm@6959
   376
fun can f x = is_some (try f x);
wenzelm@4139
   377
wenzelm@4139
   378
wenzelm@14868
   379
datatype 'a result =
wenzelm@14868
   380
  Result of 'a |
wenzelm@14868
   381
  Exn of exn;
wenzelm@14868
   382
wenzelm@14868
   383
fun capture f x = Result (f x) handle e => Exn e;
wenzelm@14868
   384
wenzelm@14868
   385
fun release (Result y) = y
wenzelm@14868
   386
  | release (Exn e) = raise e;
wenzelm@14868
   387
skalberg@15531
   388
fun get_result (Result x) = SOME x
skalberg@15531
   389
  | get_result _ = NONE;
wenzelm@14868
   390
skalberg@15531
   391
fun get_exn (Exn exn) = SOME exn
skalberg@15531
   392
  | get_exn _ = NONE;
wenzelm@14868
   393
wenzelm@14868
   394
wenzelm@18681
   395
(* errors *)
wenzelm@18681
   396
wenzelm@18681
   397
exception ERROR of string;
wenzelm@18681
   398
wenzelm@18681
   399
fun error msg = raise ERROR msg;
wenzelm@18681
   400
wenzelm@18681
   401
fun cat_error "" msg = error msg
wenzelm@18681
   402
  | cat_error msg1 msg2 = error (msg1 ^ "\n" ^ msg2);
wenzelm@18681
   403
wenzelm@18681
   404
fun sys_error msg = error ("## SYSTEM ERROR ##\n" ^ msg);
wenzelm@18681
   405
wenzelm@18681
   406
fun assert p msg = if p then () else error msg;
wenzelm@18681
   407
fun deny p msg = if p then error msg else ();
wenzelm@18681
   408
wenzelm@18681
   409
fun assert_all pred list msg =
wenzelm@18681
   410
  let
wenzelm@18681
   411
    fun ass [] = ()
wenzelm@18681
   412
      | ass (x :: xs) = if pred x then ass xs else error (msg x);
wenzelm@18681
   413
  in ass list end;
wenzelm@18681
   414
wenzelm@18681
   415
wenzelm@4139
   416
wenzelm@233
   417
(** pairs **)
wenzelm@233
   418
wenzelm@233
   419
fun pair x y = (x, y);
wenzelm@233
   420
fun rpair x y = (y, x);
wenzelm@233
   421
wenzelm@233
   422
fun fst (x, y) = x;
wenzelm@233
   423
fun snd (x, y) = y;
wenzelm@233
   424
haftmann@17498
   425
fun eq_fst eq ((x1, _), (x2, _)) = eq (x1, x2);
haftmann@17498
   426
fun eq_snd eq ((_, y1), (_, y2)) = eq (y1, y2);
wenzelm@233
   427
wenzelm@233
   428
fun swap (x, y) = (y, x);
wenzelm@233
   429
wenzelm@4212
   430
(*apply function to components*)
wenzelm@233
   431
fun apfst f (x, y) = (f x, y);
wenzelm@233
   432
fun apsnd f (x, y) = (x, f y);
wenzelm@4212
   433
fun pairself f (x, y) = (f x, f y);
wenzelm@233
   434
wenzelm@233
   435
wenzelm@233
   436
wenzelm@233
   437
(** booleans **)
wenzelm@233
   438
wenzelm@233
   439
(* equality *)
wenzelm@233
   440
wenzelm@233
   441
fun equal x y = x = y;
wenzelm@233
   442
fun not_equal x y = x <> y;
wenzelm@233
   443
wenzelm@233
   444
wenzelm@233
   445
(* operators for combining predicates *)
wenzelm@233
   446
wenzelm@16721
   447
fun p orf q = fn x => p x orelse q x;
wenzelm@16721
   448
fun p andf q = fn x => p x andalso q x;
wenzelm@233
   449
wenzelm@233
   450
wenzelm@233
   451
(* predicates on lists *)
wenzelm@233
   452
wenzelm@233
   453
(*exists pred [x1, ..., xn] ===> pred x1 orelse ... orelse pred xn*)
wenzelm@233
   454
fun exists (pred: 'a -> bool) : 'a list -> bool =
wenzelm@233
   455
  let fun boolf [] = false
wenzelm@233
   456
        | boolf (x :: xs) = pred x orelse boolf xs
wenzelm@233
   457
  in boolf end;
wenzelm@233
   458
wenzelm@233
   459
(*forall pred [x1, ..., xn] ===> pred x1 andalso ... andalso pred xn*)
wenzelm@233
   460
fun forall (pred: 'a -> bool) : 'a list -> bool =
wenzelm@233
   461
  let fun boolf [] = true
wenzelm@233
   462
        | boolf (x :: xs) = pred x andalso boolf xs
wenzelm@233
   463
  in boolf end;
clasohm@0
   464
wenzelm@233
   465
wenzelm@380
   466
(* flags *)
wenzelm@380
   467
wenzelm@380
   468
fun set flag = (flag := true; true);
wenzelm@380
   469
fun reset flag = (flag := false; false);
wenzelm@380
   470
fun toggle flag = (flag := not (! flag); ! flag);
wenzelm@380
   471
wenzelm@9118
   472
fun change r f = r := f (! r);
wenzelm@9118
   473
wenzelm@14826
   474
(*temporarily set flag, handling exceptions*)
wenzelm@2978
   475
fun setmp flag value f x =
wenzelm@2958
   476
  let
wenzelm@2958
   477
    val orig_value = ! flag;
wenzelm@2958
   478
    fun return y = (flag := orig_value; y);
wenzelm@2958
   479
  in
wenzelm@2958
   480
    flag := value;
wenzelm@2958
   481
    return (f x handle exn => (return (); raise exn))
wenzelm@2958
   482
  end;
wenzelm@2958
   483
wenzelm@380
   484
wenzelm@11853
   485
(* conditional execution *)
wenzelm@11853
   486
wenzelm@11853
   487
fun conditional b f = if b then f () else ();
wenzelm@11853
   488
wenzelm@11853
   489
wenzelm@233
   490
wenzelm@233
   491
(** lists **)
wenzelm@233
   492
skalberg@15570
   493
exception UnequalLengths;
wenzelm@233
   494
wenzelm@233
   495
fun cons x xs = x :: xs;
wenzelm@5285
   496
fun single x = [x];
wenzelm@233
   497
wenzelm@4629
   498
fun append xs ys = xs @ ys;
wenzelm@4629
   499
wenzelm@5904
   500
fun apply [] x = x
wenzelm@5904
   501
  | apply (f :: fs) x = apply fs (f x);
wenzelm@5904
   502
wenzelm@233
   503
wenzelm@233
   504
(* fold *)
wenzelm@233
   505
wenzelm@16654
   506
fun fold f =
wenzelm@16654
   507
  let
wenzelm@16654
   508
    fun fold_aux [] y = y
wenzelm@16654
   509
      | fold_aux (x :: xs) y = fold_aux xs (f x y);
wenzelm@16654
   510
  in fold_aux end;
wenzelm@15760
   511
wenzelm@16654
   512
fun fold_rev f =
wenzelm@16654
   513
  let
wenzelm@16654
   514
    fun fold_aux [] y = y
wenzelm@16654
   515
      | fold_aux (x :: xs) y = f x (fold_aux xs y);
wenzelm@16654
   516
  in fold_aux end;
wenzelm@16654
   517
haftmann@16869
   518
fun fold_map f =
haftmann@16691
   519
  let
haftmann@16691
   520
    fun fold_aux [] y = ([], y)
haftmann@16691
   521
      | fold_aux (x :: xs) y =
haftmann@16691
   522
          let
wenzelm@16705
   523
            val (x', y') = f x y;
wenzelm@16705
   524
            val (xs', y'') = fold_aux xs y';
haftmann@16691
   525
          in (x' :: xs', y'') end;
haftmann@16691
   526
  in fold_aux end;
haftmann@16691
   527
wenzelm@233
   528
(*the following versions of fold are designed to fit nicely with infixes*)
clasohm@0
   529
wenzelm@233
   530
(*  (op @) (e, [x1, ..., xn])  ===>  ((e @ x1) @ x2) ... @ xn
wenzelm@233
   531
    for operators that associate to the left (TAIL RECURSIVE)*)
wenzelm@233
   532
fun foldl (f: 'a * 'b -> 'a) : 'a * 'b list -> 'a =
wenzelm@233
   533
  let fun itl (e, [])  = e
wenzelm@233
   534
        | itl (e, a::l) = itl (f(e, a), l)
wenzelm@233
   535
  in  itl end;
wenzelm@233
   536
wenzelm@233
   537
(*  (op @) ([x1, ..., xn], e)  ===>   x1 @ (x2 ... @ (xn @ e))
wenzelm@233
   538
    for operators that associate to the right (not tail recursive)*)
wenzelm@233
   539
fun foldr f (l, e) =
wenzelm@233
   540
  let fun itr [] = e
wenzelm@233
   541
        | itr (a::l) = f(a, itr l)
wenzelm@233
   542
  in  itr l  end;
wenzelm@233
   543
wenzelm@233
   544
(*  (op @) [x1, ..., xn]  ===>   x1 @ (x2 ... @ (x[n-1] @ xn))
wenzelm@233
   545
    for n > 0, operators that associate to the right (not tail recursive)*)
wenzelm@233
   546
fun foldr1 f l =
wenzelm@4181
   547
  let fun itr [x] = x
wenzelm@233
   548
        | itr (x::l) = f(x, itr l)
wenzelm@233
   549
  in  itr l  end;
wenzelm@233
   550
haftmann@18050
   551
fun fold_index f =
haftmann@18050
   552
  let
haftmann@18514
   553
    fun fold_aux _ [] y = y
haftmann@18050
   554
      | fold_aux i (x :: xs) y = fold_aux (i+1) xs (f (i, x) y);
haftmann@18050
   555
  in fold_aux 0 end;
wenzelm@14792
   556
wenzelm@16705
   557
fun foldl_map f =
wenzelm@16705
   558
  let
wenzelm@16705
   559
    fun fold_aux (x, []) = (x, [])
wenzelm@16705
   560
      | fold_aux (x, y :: ys) =
wenzelm@16705
   561
          let
wenzelm@16705
   562
            val (x', y') = f (x, y);
wenzelm@16705
   563
            val (x'', ys') = fold_aux (x', ys);
wenzelm@16705
   564
          in (x'', y' :: ys') end;
wenzelm@16705
   565
  in fold_aux end;
wenzelm@16705
   566
wenzelm@233
   567
wenzelm@233
   568
(* basic list functions *)
wenzelm@233
   569
wenzelm@233
   570
(*take the first n elements from a list*)
wenzelm@233
   571
fun take (n, []) = []
wenzelm@233
   572
  | take (n, x :: xs) =
wenzelm@233
   573
      if n > 0 then x :: take (n - 1, xs) else [];
wenzelm@233
   574
wenzelm@233
   575
(*drop the first n elements from a list*)
wenzelm@233
   576
fun drop (n, []) = []
wenzelm@233
   577
  | drop (n, x :: xs) =
wenzelm@233
   578
      if n > 0 then drop (n - 1, xs) else x :: xs;
clasohm@0
   579
nipkow@13629
   580
fun splitAt(n,[]) = ([],[])
nipkow@13629
   581
  | splitAt(n,xs as x::ys) =
nipkow@13629
   582
      if n>0 then let val (ps,qs) = splitAt(n-1,ys) in (x::ps,qs) end
nipkow@13629
   583
      else ([],xs)
nipkow@13629
   584
nipkow@4713
   585
fun dropwhile P [] = []
nipkow@4713
   586
  | dropwhile P (ys as x::xs) = if P x then dropwhile P xs else ys;
nipkow@4713
   587
wenzelm@233
   588
(*return nth element of a list, where 0 designates the first element;
wenzelm@18461
   589
  raise Subscript if list too short*)
haftmann@18011
   590
fun nth xs i = List.nth (xs, i);
wenzelm@233
   591
wenzelm@18461
   592
fun nth_list xss i = nth xss i handle Subscript => [];
wenzelm@18461
   593
haftmann@18011
   594
(*update nth element*)
haftmann@18011
   595
fun nth_update (n, x) xs =
haftmann@18011
   596
    (case splitAt (n, xs) of
haftmann@18011
   597
      (_, []) => raise Subscript
haftmann@18011
   598
    | (prfx, _ :: sffx') => prfx @ (x :: sffx'))
haftmann@18011
   599
haftmann@18011
   600
fun nth_map 0 f (x :: xs) = f x :: xs
haftmann@18011
   601
  | nth_map n f (x :: xs) = x :: nth_map (n - 1) f xs
haftmann@18011
   602
  | nth_map _ _ [] = raise Subscript;
wenzelm@11773
   603
haftmann@18514
   604
fun map_index f =
haftmann@18514
   605
  let
haftmann@18514
   606
    fun mapp _ [] = []
haftmann@18514
   607
      | mapp i (x :: xs) = f (i, x) :: mapp (i+1) xs
haftmann@18514
   608
  in mapp 0 end;
haftmann@18514
   609
skalberg@15570
   610
val last_elem = List.last;
wenzelm@233
   611
wenzelm@3762
   612
(*rear decomposition*)
skalberg@15570
   613
fun split_last [] = raise Empty
wenzelm@3762
   614
  | split_last [x] = ([], x)
wenzelm@3762
   615
  | split_last (x :: xs) = apfst (cons x) (split_last xs);
wenzelm@3762
   616
wenzelm@4212
   617
(*find the position of an element in a list*)
wenzelm@4212
   618
fun find_index pred =
wenzelm@4212
   619
  let fun find _ [] = ~1
wenzelm@4212
   620
        | find n (x :: xs) = if pred x then n else find (n + 1) xs;
wenzelm@4212
   621
  in find 0 end;
wenzelm@3762
   622
wenzelm@4224
   623
fun find_index_eq x = find_index (equal x);
wenzelm@4212
   624
wenzelm@4212
   625
(*find first element satisfying predicate*)
skalberg@15531
   626
fun find_first _ [] = NONE
wenzelm@4212
   627
  | find_first pred (x :: xs) =
skalberg@15531
   628
      if pred x then SOME x else find_first pred xs;
wenzelm@233
   629
wenzelm@4916
   630
(*get first element by lookup function*)
skalberg@15531
   631
fun get_first _ [] = NONE
wenzelm@4916
   632
  | get_first f (x :: xs) =
wenzelm@4916
   633
      (case f x of
skalberg@15531
   634
        NONE => get_first f xs
wenzelm@4916
   635
      | some => some);
wenzelm@4916
   636
wenzelm@233
   637
(*flatten a list of lists to a list*)
skalberg@15531
   638
val flat = List.concat;
wenzelm@233
   639
wenzelm@12136
   640
fun unflat (xs :: xss) ys =
nipkow@13629
   641
      let val (ps,qs) = splitAt(length xs,ys)
nipkow@13629
   642
      in ps :: unflat xss qs end
wenzelm@12136
   643
  | unflat [] [] = []
skalberg@15570
   644
  | unflat _ _ = raise UnequalLengths;
wenzelm@12136
   645
haftmann@18441
   646
fun burrow f xss =
haftmann@18359
   647
  unflat xss ((f o flat) xss);
haftmann@18359
   648
haftmann@18549
   649
fun fold_burrow f xss s =
haftmann@18549
   650
  apfst (unflat xss) (f (flat xss) s);
haftmann@18359
   651
wenzelm@233
   652
(*like Lisp's MAPC -- seq proc [x1, ..., xn] evaluates
wenzelm@233
   653
  (proc x1; ...; proc xn) for side effects*)
skalberg@15570
   654
val seq = List.app;
wenzelm@233
   655
wenzelm@233
   656
(*separate s [x1, x2, ..., xn]  ===>  [x1, s, x2, s, ..., s, xn]*)
wenzelm@233
   657
fun separate s (x :: (xs as _ :: _)) = x :: s :: separate s xs
wenzelm@233
   658
  | separate _ xs = xs;
wenzelm@233
   659
wenzelm@233
   660
(*make the list [x, x, ..., x] of length n*)
wenzelm@233
   661
fun replicate n (x: 'a) : 'a list =
wenzelm@233
   662
  let fun rep (0, xs) = xs
wenzelm@233
   663
        | rep (n, xs) = rep (n - 1, x :: xs)
wenzelm@233
   664
  in
skalberg@15570
   665
    if n < 0 then raise Subscript
wenzelm@233
   666
    else rep (n, [])
wenzelm@233
   667
  end;
wenzelm@233
   668
wenzelm@14926
   669
fun translate_string f = String.translate (f o String.str);
wenzelm@14926
   670
wenzelm@4248
   671
(*multiply [a, b, c, ...] * [xs, ys, zs, ...]*)
wenzelm@18148
   672
fun multiply [] _ = []
wenzelm@18148
   673
  | multiply (x :: xs) yss = map (cons x) yss @ multiply xs yss;
wenzelm@4248
   674
wenzelm@14792
   675
(*direct product*)
wenzelm@14792
   676
fun product _ [] = []
wenzelm@14792
   677
  | product [] _ = []
wenzelm@14792
   678
  | product (x :: xs) ys = map (pair x) ys @ product xs ys;
wenzelm@14792
   679
wenzelm@233
   680
wenzelm@233
   681
(* filter *)
wenzelm@233
   682
wenzelm@233
   683
(*copy the list preserving elements that satisfy the predicate*)
skalberg@15531
   684
val filter = List.filter;
clasohm@0
   685
fun filter_out f = filter (not o f);
skalberg@15570
   686
val mapfilter = List.mapPartial;
wenzelm@233
   687
wenzelm@233
   688
wenzelm@233
   689
(* lists of pairs *)
wenzelm@233
   690
skalberg@15570
   691
exception UnequalLengths;
skalberg@15570
   692
haftmann@18330
   693
fun map2 _ [] [] = []
haftmann@18330
   694
  | map2 f (x :: xs) (y :: ys) = f x y :: map2 f xs ys
haftmann@18330
   695
  | map2 _ _ _ = raise UnequalLengths;
wenzelm@380
   696
haftmann@18330
   697
fun fold2 f =
haftmann@18330
   698
  let
haftmann@18330
   699
    fun fold_aux [] [] z = z
haftmann@18330
   700
      | fold_aux (x :: xs) (y :: ys) z = fold_aux xs ys (f x y z)
haftmann@18330
   701
      | fold_aux _ _ _ = raise UnequalLengths;
haftmann@18330
   702
  in fold_aux end;
wenzelm@380
   703
wenzelm@4956
   704
wenzelm@233
   705
(*combine two lists forming a list of pairs:
wenzelm@233
   706
  [x1, ..., xn] ~~ [y1, ..., yn]  ===>  [(x1, y1), ..., (xn, yn)]*)
wenzelm@233
   707
fun [] ~~ [] = []
wenzelm@233
   708
  | (x :: xs) ~~ (y :: ys) = (x, y) :: (xs ~~ ys)
skalberg@15570
   709
  | _ ~~ _ = raise UnequalLengths;
wenzelm@233
   710
wenzelm@233
   711
(*inverse of ~~; the old 'split':
wenzelm@233
   712
  [(x1, y1), ..., (xn, yn)]  ===>  ([x1, ..., xn], [y1, ..., yn])*)
skalberg@15570
   713
val split_list = ListPair.unzip;
wenzelm@233
   714
haftmann@18330
   715
fun equal_lists eq (xs, ys) =
haftmann@18330
   716
  let
haftmann@18330
   717
    fun eq' [] [] = true
haftmann@18330
   718
      | eq' (x :: xs) (y :: ys) = eq (x, y) andalso eq' xs ys
haftmann@18330
   719
  in length xs = length ys andalso eq' xs ys end;
wenzelm@7468
   720
wenzelm@233
   721
wenzelm@233
   722
(* prefixes, suffixes *)
wenzelm@233
   723
haftmann@18441
   724
fun is_prefix _ [] _ = true
haftmann@18441
   725
  | is_prefix eq (x :: xs) (y :: ys) = eq (x, y) andalso is_prefix eq xs ys
haftmann@18441
   726
  | is_prefix eq _ _ = false;
wenzelm@233
   727
wenzelm@233
   728
(* [x1, ..., xi, ..., xn]  --->  ([x1, ..., x(i-1)], [xi, ..., xn])
wenzelm@233
   729
   where xi is the first element that does not satisfy the predicate*)
wenzelm@233
   730
fun take_prefix (pred : 'a -> bool)  (xs: 'a list) : 'a list * 'a list =
wenzelm@233
   731
  let fun take (rxs, []) = (rev rxs, [])
wenzelm@255
   732
        | take (rxs, x :: xs) =
wenzelm@255
   733
            if  pred x  then  take(x :: rxs, xs)  else  (rev rxs, x :: xs)
wenzelm@233
   734
  in  take([], xs)  end;
wenzelm@233
   735
wenzelm@233
   736
(* [x1, ..., xi, ..., xn]  --->  ([x1, ..., xi], [x(i+1), ..., xn])
wenzelm@233
   737
   where xi is the last element that does not satisfy the predicate*)
wenzelm@233
   738
fun take_suffix _ [] = ([], [])
wenzelm@233
   739
  | take_suffix pred (x :: xs) =
wenzelm@233
   740
      (case take_suffix pred xs of
wenzelm@233
   741
        ([], sffx) => if pred x then ([], x :: sffx) else ([x], sffx)
wenzelm@233
   742
      | (prfx, sffx) => (x :: prfx, sffx));
wenzelm@233
   743
wenzelm@12249
   744
fun prefixes1 [] = []
wenzelm@12249
   745
  | prefixes1 (x :: xs) = map (cons x) ([] :: prefixes1 xs);
wenzelm@12249
   746
wenzelm@12249
   747
fun suffixes1 xs = map rev (prefixes1 (rev xs));
wenzelm@12249
   748
wenzelm@233
   749
wenzelm@233
   750
wenzelm@233
   751
(** integers **)
wenzelm@233
   752
wenzelm@16439
   753
fun gcd (x, y) =
paulson@15965
   754
  let fun gxd x y : IntInf.int =
nipkow@10692
   755
    if y = 0 then x else gxd y (x mod y)
nipkow@10692
   756
  in if x < y then gxd y x else gxd x y end;
nipkow@10692
   757
wenzelm@16439
   758
fun lcm (x, y) = (x * y) div gcd (x, y);
nipkow@10692
   759
wenzelm@2958
   760
fun inc i = (i := ! i + 1; ! i);
wenzelm@2958
   761
fun dec i = (i := ! i - 1; ! i);
wenzelm@233
   762
wenzelm@233
   763
wenzelm@233
   764
(* lists of integers *)
wenzelm@233
   765
wenzelm@233
   766
(*make the list [from, from + 1, ..., to]*)
paulson@2175
   767
fun (from upto to) =
wenzelm@233
   768
  if from > to then [] else from :: ((from + 1) upto to);
wenzelm@233
   769
wenzelm@233
   770
(*make the list [from, from - 1, ..., to]*)
paulson@2175
   771
fun (from downto to) =
wenzelm@233
   772
  if from < to then [] else from :: ((from - 1) downto to);
wenzelm@233
   773
wenzelm@233
   774
(*predicate: downto0 (is, n) <=> is = [n, n - 1, ..., 0]*)
wenzelm@233
   775
fun downto0 (i :: is, n) = i = n andalso downto0 (is, n - 1)
wenzelm@233
   776
  | downto0 ([], n) = n = ~1;
wenzelm@233
   777
wenzelm@233
   778
wenzelm@233
   779
(* convert integers to strings *)
wenzelm@233
   780
wenzelm@233
   781
(*expand the number in the given base;
wenzelm@233
   782
  example: radixpand (2, 8) gives [1, 0, 0, 0]*)
wenzelm@233
   783
fun radixpand (base, num) : int list =
wenzelm@233
   784
  let
wenzelm@233
   785
    fun radix (n, tail) =
wenzelm@233
   786
      if n < base then n :: tail
wenzelm@233
   787
      else radix (n div base, (n mod base) :: tail)
wenzelm@233
   788
  in radix (num, []) end;
wenzelm@233
   789
wenzelm@233
   790
(*expands a number into a string of characters starting from "zerochar";
wenzelm@233
   791
  example: radixstring (2, "0", 8) gives "1000"*)
wenzelm@233
   792
fun radixstring (base, zerochar, num) =
wenzelm@233
   793
  let val offset = ord zerochar;
wenzelm@233
   794
      fun chrof n = chr (offset + n)
wenzelm@233
   795
  in implode (map chrof (radixpand (base, num))) end;
wenzelm@233
   796
wenzelm@233
   797
paulson@3407
   798
val string_of_int = Int.toString;
wenzelm@233
   799
paulson@3407
   800
fun string_of_indexname (a,0) = a
paulson@3407
   801
  | string_of_indexname (a,i) = a ^ "_" ^ Int.toString i;
wenzelm@233
   802
wenzelm@233
   803
wenzelm@14826
   804
(* read integers *)
wenzelm@14826
   805
wenzelm@14826
   806
fun read_radixint (radix: int, cs) : int * string list =
wenzelm@14826
   807
  let val zero = ord"0"
wenzelm@14826
   808
      val limit = zero+radix
wenzelm@14826
   809
      fun scan (num,[]) = (num,[])
wenzelm@14826
   810
        | scan (num, c::cs) =
wenzelm@14826
   811
              if  zero <= ord c  andalso  ord c < limit
wenzelm@14826
   812
              then scan(radix*num + ord c - zero, cs)
wenzelm@14826
   813
              else (num, c::cs)
wenzelm@14826
   814
  in  scan(0,cs)  end;
wenzelm@14826
   815
wenzelm@14826
   816
fun read_int cs = read_radixint (10, cs);
wenzelm@14826
   817
wenzelm@14826
   818
fun oct_char s = chr (#1 (read_radixint (8, explode s)));
wenzelm@14826
   819
wenzelm@14826
   820
wenzelm@14826
   821
wenzelm@233
   822
(** strings **)
wenzelm@233
   823
wenzelm@16188
   824
(* functions tuned for strings, avoiding explode *)
wenzelm@6312
   825
haftmann@18011
   826
fun nth_string str i =
wenzelm@6959
   827
  (case try String.substring (str, i, 1) of
skalberg@15531
   828
    SOME s => s
skalberg@15570
   829
  | NONE => raise Subscript);
wenzelm@6312
   830
wenzelm@16188
   831
fun fold_string f str x0 =
wenzelm@6282
   832
  let
wenzelm@6282
   833
    val n = size str;
wenzelm@16188
   834
    fun iter (x, i) =
wenzelm@16188
   835
      if i < n then iter (f (String.substring (str, i, 1)) x, i + 1) else x;
wenzelm@16188
   836
  in iter (x0, 0) end;
wenzelm@6282
   837
wenzelm@14968
   838
fun exists_string pred str =
wenzelm@14968
   839
  let
wenzelm@14968
   840
    val n = size str;
wenzelm@14968
   841
    fun ex i = i < n andalso (pred (String.substring (str, i, 1)) orelse ex (i + 1));
wenzelm@14968
   842
  in ex 0 end;
wenzelm@6312
   843
wenzelm@16188
   844
fun forall_string pred = not o exists_string (not o pred);
wenzelm@16188
   845
lcp@512
   846
(*enclose in brackets*)
lcp@512
   847
fun enclose lpar rpar str = lpar ^ str ^ rpar;
wenzelm@6642
   848
fun unenclose str = String.substring (str, 1, size str - 2);
wenzelm@255
   849
wenzelm@233
   850
(*simple quoting (does not escape special chars)*)
lcp@512
   851
val quote = enclose "\"" "\"";
wenzelm@233
   852
wenzelm@4212
   853
(*space_implode "..." (explode "hello") = "h...e...l...l...o"*)
wenzelm@233
   854
fun space_implode a bs = implode (separate a bs);
wenzelm@233
   855
wenzelm@255
   856
val commas = space_implode ", ";
wenzelm@380
   857
val commas_quote = commas o map quote;
wenzelm@255
   858
wenzelm@233
   859
(*concatenate messages, one per line, into a string*)
wenzelm@255
   860
val cat_lines = space_implode "\n";
wenzelm@233
   861
wenzelm@4212
   862
(*space_explode "." "h.e..l.lo" = ["h", "e", "", "l", "lo"]*)
wenzelm@3832
   863
fun space_explode _ "" = []
wenzelm@3832
   864
  | space_explode sep str =
wenzelm@3832
   865
      let
wenzelm@3832
   866
        fun expl chs =
wenzelm@3832
   867
          (case take_prefix (not_equal sep) chs of
wenzelm@3832
   868
            (cs, []) => [implode cs]
wenzelm@3832
   869
          | (cs, _ :: cs') => implode cs :: expl cs');
wenzelm@3832
   870
      in expl (explode str) end;
wenzelm@3832
   871
wenzelm@3832
   872
val split_lines = space_explode "\n";
wenzelm@3832
   873
wenzelm@14826
   874
fun prefix_lines "" txt = txt
wenzelm@14826
   875
  | prefix_lines prfx txt = txt |> split_lines |> map (fn s => prfx ^ s) |> cat_lines;
wenzelm@14826
   876
wenzelm@7712
   877
fun untabify chs =
wenzelm@7712
   878
  let
wenzelm@7712
   879
    val tab_width = 8;
wenzelm@7712
   880
wenzelm@7712
   881
    fun untab (_, "\n") = (0, ["\n"])
wenzelm@9118
   882
      | untab (pos, "\t") =
wenzelm@9118
   883
          let val d = tab_width - (pos mod tab_width) in (pos + d, replicate d " ") end
wenzelm@7712
   884
      | untab (pos, c) = (pos + 1, [c]);
wenzelm@7712
   885
  in
wenzelm@7712
   886
    if not (exists (equal "\t") chs) then chs
wenzelm@7712
   887
    else flat (#2 (foldl_map untab (0, chs)))
wenzelm@7712
   888
  end;
wenzelm@7712
   889
wenzelm@18681
   890
fun prefix prfx s = prfx ^ s;
wenzelm@16188
   891
fun suffix sffx s = s ^ sffx;
wenzelm@5285
   892
wenzelm@18681
   893
fun unprefix prfx s =
wenzelm@18681
   894
  if String.isPrefix prfx s then String.substring (s, size prfx, size s - size prfx)
wenzelm@18681
   895
  else raise Fail "unprefix";
wenzelm@18681
   896
wenzelm@16188
   897
fun unsuffix sffx s =
wenzelm@17061
   898
  if String.isSuffix sffx s then String.substring (s, 0, size s - size sffx)
wenzelm@17061
   899
  else raise Fail "unsuffix";
wenzelm@5285
   900
wenzelm@10951
   901
fun replicate_string 0 _ = ""
wenzelm@10951
   902
  | replicate_string 1 a = a
wenzelm@10951
   903
  | replicate_string k a =
wenzelm@10951
   904
      if k mod 2 = 0 then replicate_string (k div 2) (a ^ a)
wenzelm@10951
   905
      else replicate_string (k div 2) (a ^ a) ^ a;
wenzelm@10951
   906
wenzelm@3832
   907
wenzelm@233
   908
wenzelm@16492
   909
(** lists as sets -- see also Pure/General/ord_list.ML **)
wenzelm@233
   910
wenzelm@233
   911
(*membership in a list*)
wenzelm@233
   912
fun x mem [] = false
wenzelm@233
   913
  | x mem (y :: ys) = x = y orelse x mem ys;
clasohm@0
   914
paulson@2175
   915
(*membership in a list, optimized version for ints*)
berghofe@1576
   916
fun (x:int) mem_int [] = false
berghofe@1576
   917
  | x mem_int (y :: ys) = x = y orelse x mem_int ys;
berghofe@1576
   918
paulson@2175
   919
(*membership in a list, optimized version for strings*)
berghofe@1576
   920
fun (x:string) mem_string [] = false
berghofe@1576
   921
  | x mem_string (y :: ys) = x = y orelse x mem_string ys;
berghofe@1576
   922
clasohm@0
   923
(*generalized membership test*)
wenzelm@233
   924
fun gen_mem eq (x, []) = false
wenzelm@233
   925
  | gen_mem eq (x, y :: ys) = eq (x, y) orelse gen_mem eq (x, ys);
wenzelm@233
   926
wenzelm@16492
   927
(*member, insert, and remove -- with canonical argument order*)
wenzelm@16492
   928
fun member eq xs x = gen_mem eq (x, xs);
wenzelm@15760
   929
fun insert eq x xs = if gen_mem eq (x, xs) then xs else x :: xs;
wenzelm@15760
   930
fun remove eq x xs = if gen_mem eq (x, xs) then filter_out (fn y => eq (x, y)) xs else xs;
wenzelm@233
   931
wenzelm@233
   932
(*insertion into list if not already there*)
paulson@2175
   933
fun (x ins xs) = if x mem xs then xs else x :: xs;
clasohm@0
   934
paulson@2175
   935
(*insertion into list, optimized version for ints*)
paulson@2175
   936
fun (x ins_int xs) = if x mem_int xs then xs else x :: xs;
berghofe@1576
   937
paulson@2175
   938
(*insertion into list, optimized version for strings*)
paulson@2175
   939
fun (x ins_string xs) = if x mem_string xs then xs else x :: xs;
berghofe@1576
   940
clasohm@0
   941
(*generalized insertion*)
wenzelm@15760
   942
fun gen_ins eq (x, xs) = insert eq x xs;
wenzelm@233
   943
wenzelm@233
   944
(*union of sets represented as lists: no repetitions*)
wenzelm@233
   945
fun xs union [] = xs
wenzelm@233
   946
  | [] union ys = ys
wenzelm@233
   947
  | (x :: xs) union ys = xs union (x ins ys);
clasohm@0
   948
paulson@2175
   949
(*union of sets, optimized version for ints*)
berghofe@1576
   950
fun (xs:int list) union_int [] = xs
berghofe@1576
   951
  | [] union_int ys = ys
berghofe@1576
   952
  | (x :: xs) union_int ys = xs union_int (x ins_int ys);
berghofe@1576
   953
paulson@2175
   954
(*union of sets, optimized version for strings*)
berghofe@1576
   955
fun (xs:string list) union_string [] = xs
berghofe@1576
   956
  | [] union_string ys = ys
berghofe@1576
   957
  | (x :: xs) union_string ys = xs union_string (x ins_string ys);
berghofe@1576
   958
clasohm@0
   959
(*generalized union*)
wenzelm@233
   960
fun gen_union eq (xs, []) = xs
wenzelm@233
   961
  | gen_union eq ([], ys) = ys
wenzelm@233
   962
  | gen_union eq (x :: xs, ys) = gen_union eq (xs, gen_ins eq (x, ys));
wenzelm@233
   963
wenzelm@233
   964
wenzelm@233
   965
(*intersection*)
wenzelm@233
   966
fun [] inter ys = []
wenzelm@233
   967
  | (x :: xs) inter ys =
wenzelm@233
   968
      if x mem ys then x :: (xs inter ys) else xs inter ys;
wenzelm@233
   969
paulson@2175
   970
(*intersection, optimized version for ints*)
berghofe@1576
   971
fun ([]:int list) inter_int ys = []
berghofe@1576
   972
  | (x :: xs) inter_int ys =
berghofe@1576
   973
      if x mem_int ys then x :: (xs inter_int ys) else xs inter_int ys;
berghofe@1576
   974
paulson@2175
   975
(*intersection, optimized version for strings *)
berghofe@1576
   976
fun ([]:string list) inter_string ys = []
berghofe@1576
   977
  | (x :: xs) inter_string ys =
berghofe@1576
   978
      if x mem_string ys then x :: (xs inter_string ys) else xs inter_string ys;
berghofe@1576
   979
paulson@7090
   980
(*generalized intersection*)
paulson@7090
   981
fun gen_inter eq ([], ys) = []
wenzelm@12284
   982
  | gen_inter eq (x::xs, ys) =
paulson@7090
   983
      if gen_mem eq (x,ys) then x :: gen_inter eq (xs, ys)
wenzelm@12284
   984
                           else      gen_inter eq (xs, ys);
paulson@7090
   985
wenzelm@233
   986
wenzelm@233
   987
(*subset*)
wenzelm@233
   988
fun [] subset ys = true
wenzelm@233
   989
  | (x :: xs) subset ys = x mem ys andalso xs subset ys;
wenzelm@233
   990
paulson@2175
   991
(*subset, optimized version for ints*)
wenzelm@16439
   992
fun ([]: int list) subset_int ys = true
berghofe@1576
   993
  | (x :: xs) subset_int ys = x mem_int ys andalso xs subset_int ys;
berghofe@1576
   994
paulson@2175
   995
(*subset, optimized version for strings*)
wenzelm@16439
   996
fun ([]: string list) subset_string ys = true
berghofe@1576
   997
  | (x :: xs) subset_string ys = x mem_string ys andalso xs subset_string ys;
berghofe@1576
   998
wenzelm@4363
   999
(*set equality*)
wenzelm@4363
  1000
fun eq_set (xs, ys) =
wenzelm@4363
  1001
  xs = ys orelse (xs subset ys andalso ys subset xs);
wenzelm@4363
  1002
paulson@2182
  1003
(*set equality for strings*)
wenzelm@16439
  1004
fun eq_set_string ((xs: string list), ys) =
berghofe@1576
  1005
  xs = ys orelse (xs subset_string ys andalso ys subset_string xs);
berghofe@1576
  1006
paulson@2182
  1007
fun gen_subset eq (xs, ys) = forall (fn x => gen_mem eq (x, ys)) xs;
paulson@2182
  1008
wenzelm@265
  1009
wenzelm@233
  1010
(*removing an element from a list WITHOUT duplicates*)
wenzelm@233
  1011
fun (y :: ys) \ x = if x = y then ys else y :: (ys \ x)
wenzelm@233
  1012
  | [] \ x = [];
wenzelm@233
  1013
paulson@2243
  1014
fun ys \\ xs = foldl (op \) (ys,xs);
clasohm@0
  1015
wenzelm@233
  1016
(*removing an element from a list -- possibly WITH duplicates*)
wenzelm@233
  1017
fun gen_rem eq (xs, y) = filter_out (fn x => eq (x, y)) xs;
wenzelm@12295
  1018
fun gen_rems eq (xs, ys) = filter_out (fn x => gen_mem eq (x, ys)) xs;
wenzelm@233
  1019
wenzelm@233
  1020
(*makes a list of the distinct members of the input; preserves order, takes
wenzelm@233
  1021
  first of equal elements*)
wenzelm@233
  1022
fun gen_distinct eq lst =
wenzelm@233
  1023
  let
wenzelm@233
  1024
    val memb = gen_mem eq;
clasohm@0
  1025
wenzelm@233
  1026
    fun dist (rev_seen, []) = rev rev_seen
wenzelm@233
  1027
      | dist (rev_seen, x :: xs) =
wenzelm@233
  1028
          if memb (x, rev_seen) then dist (rev_seen, xs)
wenzelm@233
  1029
          else dist (x :: rev_seen, xs);
wenzelm@233
  1030
  in
wenzelm@233
  1031
    dist ([], lst)
wenzelm@233
  1032
  end;
wenzelm@233
  1033
paulson@2243
  1034
fun distinct l = gen_distinct (op =) l;
wenzelm@233
  1035
wenzelm@233
  1036
(*returns the tail beginning with the first repeated element, or []*)
wenzelm@233
  1037
fun findrep [] = []
wenzelm@233
  1038
  | findrep (x :: xs) = if x mem xs then x :: xs else findrep xs;
wenzelm@233
  1039
wenzelm@233
  1040
wenzelm@255
  1041
(*returns a list containing all repeated elements exactly once; preserves
wenzelm@255
  1042
  order, takes first of equal elements*)
wenzelm@255
  1043
fun gen_duplicates eq lst =
wenzelm@255
  1044
  let
wenzelm@255
  1045
    val memb = gen_mem eq;
wenzelm@255
  1046
wenzelm@255
  1047
    fun dups (rev_dups, []) = rev rev_dups
wenzelm@255
  1048
      | dups (rev_dups, x :: xs) =
wenzelm@255
  1049
          if memb (x, rev_dups) orelse not (memb (x, xs)) then
wenzelm@255
  1050
            dups (rev_dups, xs)
wenzelm@255
  1051
          else dups (x :: rev_dups, xs);
wenzelm@255
  1052
  in
wenzelm@255
  1053
    dups ([], lst)
wenzelm@255
  1054
  end;
wenzelm@255
  1055
paulson@2243
  1056
fun duplicates l = gen_duplicates (op =) l;
wenzelm@255
  1057
wenzelm@16878
  1058
fun has_duplicates eq =
wenzelm@16878
  1059
  let
wenzelm@16878
  1060
    fun dups [] = false
wenzelm@16878
  1061
      | dups (x :: xs) = member eq xs x orelse dups xs;
wenzelm@16878
  1062
  in dups end;
wenzelm@16878
  1063
wenzelm@255
  1064
wenzelm@233
  1065
wenzelm@233
  1066
(** association lists **)
clasohm@0
  1067
wenzelm@12284
  1068
(* lists as tables *)
wenzelm@233
  1069
wenzelm@12284
  1070
fun gen_merge_lists _ xs [] = xs
wenzelm@12284
  1071
  | gen_merge_lists _ [] ys = ys
wenzelm@12284
  1072
  | gen_merge_lists eq xs ys = xs @ gen_rems eq (ys, xs);
clasohm@0
  1073
wenzelm@12284
  1074
fun gen_merge_lists' _ xs [] = xs
wenzelm@12284
  1075
  | gen_merge_lists' _ [] ys = ys
wenzelm@12295
  1076
  | gen_merge_lists' eq xs ys = gen_rems eq (ys, xs) @ xs;
clasohm@0
  1077
wenzelm@12284
  1078
fun merge_lists xs ys = gen_merge_lists (op =) xs ys;
wenzelm@12284
  1079
fun merge_lists' xs ys = gen_merge_lists' (op =) xs ys;
haftmann@17498
  1080
fun merge_alists al = gen_merge_lists (eq_fst (op =)) al;
haftmann@17498
  1081
fun merge_alists' al = gen_merge_lists' (eq_fst (op =)) al;
wenzelm@380
  1082
clasohm@0
  1083
clasohm@0
  1084
wenzelm@233
  1085
(** balanced trees **)
wenzelm@233
  1086
wenzelm@233
  1087
exception Balance;      (*indicates non-positive argument to balancing fun*)
wenzelm@233
  1088
wenzelm@233
  1089
(*balanced folding; avoids deep nesting*)
wenzelm@233
  1090
fun fold_bal f [x] = x
wenzelm@233
  1091
  | fold_bal f [] = raise Balance
wenzelm@233
  1092
  | fold_bal f xs =
nipkow@13629
  1093
      let val (ps,qs) = splitAt(length xs div 2, xs)
nipkow@13629
  1094
      in  f (fold_bal f ps, fold_bal f qs)  end;
wenzelm@233
  1095
wenzelm@233
  1096
(*construct something of the form f(...g(...(x)...)) for balanced access*)
wenzelm@233
  1097
fun access_bal (f, g, x) n i =
wenzelm@233
  1098
  let fun acc n i =     (*1<=i<=n*)
wenzelm@233
  1099
          if n=1 then x else
wenzelm@233
  1100
          let val n2 = n div 2
wenzelm@233
  1101
          in  if i<=n2 then f (acc n2 i)
wenzelm@233
  1102
                       else g (acc (n-n2) (i-n2))
wenzelm@233
  1103
          end
wenzelm@233
  1104
  in  if 1<=i andalso i<=n then acc n i else raise Balance  end;
wenzelm@233
  1105
wenzelm@233
  1106
(*construct ALL such accesses; could try harder to share recursive calls!*)
wenzelm@233
  1107
fun accesses_bal (f, g, x) n =
wenzelm@233
  1108
  let fun acc n =
wenzelm@233
  1109
          if n=1 then [x] else
wenzelm@233
  1110
          let val n2 = n div 2
wenzelm@233
  1111
              val acc2 = acc n2
wenzelm@233
  1112
          in  if n-n2=n2 then map f acc2 @ map g acc2
wenzelm@233
  1113
                         else map f acc2 @ map g (acc (n-n2)) end
wenzelm@233
  1114
  in  if 1<=n then acc n else raise Balance  end;
wenzelm@233
  1115
wenzelm@233
  1116
wenzelm@233
  1117
wenzelm@2506
  1118
(** orders **)
wenzelm@2506
  1119
wenzelm@4445
  1120
fun rev_order LESS = GREATER
wenzelm@4445
  1121
  | rev_order EQUAL = EQUAL
wenzelm@4445
  1122
  | rev_order GREATER = LESS;
wenzelm@4445
  1123
wenzelm@4479
  1124
(*assume rel is a linear strict order*)
wenzelm@4445
  1125
fun make_ord rel (x, y) =
wenzelm@4445
  1126
  if rel (x, y) then LESS
wenzelm@4445
  1127
  else if rel (y, x) then GREATER
wenzelm@4445
  1128
  else EQUAL;
wenzelm@4445
  1129
haftmann@18452
  1130
fun eq_ord ord xy =
haftmann@18452
  1131
  case ord xy
haftmann@18452
  1132
   of EQUAL => true
haftmann@18452
  1133
    | _ => false;
haftmann@18452
  1134
wenzelm@15051
  1135
val int_ord = Int.compare;
wenzelm@15051
  1136
val string_ord = String.compare;
wenzelm@2506
  1137
wenzelm@16676
  1138
fun fast_string_ord (s1, s2) =
wenzelm@16676
  1139
  (case int_ord (size s1, size s2) of EQUAL => string_ord (s1, s2) | ord => ord);
wenzelm@16676
  1140
wenzelm@16492
  1141
fun option_ord ord (SOME x, SOME y) = ord (x, y)
wenzelm@16492
  1142
  | option_ord _ (NONE, NONE) = EQUAL
wenzelm@16492
  1143
  | option_ord _ (NONE, SOME _) = LESS
wenzelm@16492
  1144
  | option_ord _ (SOME _, NONE) = GREATER;
wenzelm@16492
  1145
wenzelm@4343
  1146
(*lexicographic product*)
wenzelm@4343
  1147
fun prod_ord a_ord b_ord ((x, y), (x', y')) =
wenzelm@4343
  1148
  (case a_ord (x, x') of EQUAL => b_ord (y, y') | ord => ord);
wenzelm@4343
  1149
wenzelm@4343
  1150
(*dictionary order -- in general NOT well-founded!*)
wenzelm@16984
  1151
fun dict_ord elem_ord (x :: xs, y :: ys) =
wenzelm@16984
  1152
      (case elem_ord (x, y) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord)
wenzelm@16984
  1153
  | dict_ord _ ([], []) = EQUAL
wenzelm@4343
  1154
  | dict_ord _ ([], _ :: _) = LESS
wenzelm@16984
  1155
  | dict_ord _ (_ :: _, []) = GREATER;
wenzelm@4343
  1156
wenzelm@4343
  1157
(*lexicographic product of lists*)
wenzelm@4343
  1158
fun list_ord elem_ord (xs, ys) =
wenzelm@16676
  1159
  (case int_ord (length xs, length ys) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord);
wenzelm@4343
  1160
wenzelm@2506
  1161
wenzelm@4621
  1162
(* sorting *)
wenzelm@4621
  1163
wenzelm@18427
  1164
(*quicksort -- stable, i.e. does not reorder equal elements*)
wenzelm@18427
  1165
fun quicksort unique ord =
wenzelm@4621
  1166
  let
wenzelm@16878
  1167
    fun qsort [] = []
wenzelm@16878
  1168
      | qsort (xs as [_]) = xs
wenzelm@18427
  1169
      | qsort (xs as [x, y]) =
wenzelm@18427
  1170
          (case ord (x, y) of
wenzelm@18427
  1171
            LESS => xs
wenzelm@18427
  1172
          | EQUAL => if unique then [x] else xs
wenzelm@18427
  1173
          | GREATER => [y, x])
wenzelm@16878
  1174
      | qsort xs =
haftmann@18011
  1175
          let val (lts, eqs, gts) = part (nth xs (length xs div 2)) xs
wenzelm@16878
  1176
          in qsort lts @ eqs @ qsort gts end
wenzelm@4621
  1177
    and part _ [] = ([], [], [])
wenzelm@4621
  1178
      | part pivot (x :: xs) = add (ord (x, pivot)) x (part pivot xs)
wenzelm@4621
  1179
    and add LESS x (lts, eqs, gts) = (x :: lts, eqs, gts)
wenzelm@18427
  1180
      | add EQUAL x (lts, [], gts) = (lts, [x], gts)
wenzelm@18427
  1181
      | add EQUAL x (res as (lts, eqs, gts)) = if unique then res else (lts, x :: eqs, gts)
wenzelm@4621
  1182
      | add GREATER x (lts, eqs, gts) = (lts, eqs, x :: gts);
wenzelm@4621
  1183
  in qsort end;
wenzelm@4621
  1184
wenzelm@18427
  1185
fun sort ord = quicksort false ord;
wenzelm@18427
  1186
fun sort_distinct ord = quicksort true ord;
wenzelm@18427
  1187
wenzelm@4621
  1188
val sort_strings = sort string_ord;
wenzelm@4621
  1189
fun sort_wrt sel xs = sort (string_ord o pairself sel) xs;
wenzelm@4621
  1190
wenzelm@4621
  1191
wenzelm@2506
  1192
berghofe@14106
  1193
(** random numbers **)
berghofe@14106
  1194
berghofe@14106
  1195
exception RANDOM;
berghofe@14106
  1196
berghofe@14618
  1197
fun rmod x y = x - y * Real.realFloor (x / y);
berghofe@14106
  1198
berghofe@14106
  1199
local
berghofe@14106
  1200
  val a = 16807.0;
berghofe@14106
  1201
  val m = 2147483647.0;
berghofe@14106
  1202
  val random_seed = ref 1.0;
berghofe@14106
  1203
in
berghofe@14106
  1204
berghofe@14106
  1205
fun random () =
berghofe@14106
  1206
  let val r = rmod (a * !random_seed) m
berghofe@14106
  1207
  in (random_seed := r; r) end;
berghofe@14106
  1208
berghofe@14106
  1209
end;
berghofe@14106
  1210
berghofe@14106
  1211
fun random_range l h =
berghofe@14106
  1212
  if h < l orelse l < 0 then raise RANDOM
berghofe@14106
  1213
  else l + Real.floor (rmod (random ()) (real (h - l + 1)));
berghofe@14106
  1214
haftmann@18011
  1215
fun one_of xs = nth xs (random_range 0 (length xs - 1));
berghofe@14106
  1216
berghofe@14106
  1217
fun frequency xs =
berghofe@14106
  1218
  let
berghofe@14106
  1219
    val sum = foldl op + (0, map fst xs);
wenzelm@17756
  1220
    fun pick n ((k: int, x) :: xs) =
berghofe@14106
  1221
      if n <= k then x else pick (n - k) xs
berghofe@14106
  1222
  in pick (random_range 1 sum) xs end;
berghofe@14106
  1223
berghofe@14106
  1224
wenzelm@14826
  1225
(** current directory **)
wenzelm@233
  1226
paulson@2243
  1227
val cd = OS.FileSys.chDir;
wenzelm@2317
  1228
val pwd = OS.FileSys.getDir;
paulson@2243
  1229
berghofe@3606
  1230
wenzelm@4621
  1231
(** misc **)
wenzelm@233
  1232
clasohm@0
  1233
(*Partition list into elements that satisfy predicate and those that don't.
wenzelm@233
  1234
  Preserves order of elements in both lists.*)
skalberg@15570
  1235
val partition = List.partition;
clasohm@0
  1236
clasohm@0
  1237
fun partition_eq (eq:'a * 'a -> bool) =
wenzelm@16842
  1238
  let
wenzelm@16842
  1239
    fun part [] = []
wenzelm@16842
  1240
      | part (x :: ys) =
wenzelm@16842
  1241
          let val (xs, xs') = partition (fn y => eq (x, y)) ys
wenzelm@16842
  1242
          in (x::xs)::(part xs') end
wenzelm@16842
  1243
  in part end;
clasohm@0
  1244
clasohm@0
  1245
wenzelm@233
  1246
(*Partition a list into buckets  [ bi, b(i+1), ..., bj ]
clasohm@0
  1247
   putting x in bk if p(k)(x) holds.  Preserve order of elements if possible.*)
clasohm@0
  1248
fun partition_list p i j =
wenzelm@233
  1249
  let fun part k xs =
wenzelm@233
  1250
            if k>j then
clasohm@0
  1251
              (case xs of [] => []
skalberg@15570
  1252
                         | _ => raise Fail "partition_list")
clasohm@0
  1253
            else
wenzelm@233
  1254
            let val (ns, rest) = partition (p k) xs;
wenzelm@233
  1255
            in  ns :: part(k+1)rest  end
clasohm@0
  1256
  in  part i end;
clasohm@0
  1257
clasohm@0
  1258
wenzelm@233
  1259
(* generating identifiers *)
clasohm@0
  1260
paulson@4063
  1261
(** Freshly generated identifiers; supplied prefix MUST start with a letter **)
clasohm@0
  1262
local
paulson@4063
  1263
(*Maps 0-63 to A-Z, a-z, 0-9 or _ or ' for generating random identifiers*)
paulson@4063
  1264
fun char i =      if i<26 then chr (ord "A" + i)
wenzelm@5904
  1265
             else if i<52 then chr (ord "a" + i - 26)
wenzelm@5904
  1266
             else if i<62 then chr (ord"0" + i - 52)
wenzelm@5904
  1267
             else if i=62 then "_"
wenzelm@5904
  1268
             else  (*i=63*)    "'";
paulson@4063
  1269
paulson@4063
  1270
val charVec = Vector.tabulate (64, char);
paulson@4063
  1271
wenzelm@5904
  1272
fun newid n =
wenzelm@5904
  1273
  let
wenzelm@4284
  1274
  in  implode (map (fn i => Vector.sub(charVec,i)) (radixpand (64,n)))  end;
paulson@2003
  1275
wenzelm@4284
  1276
val seedr = ref 0;
clasohm@0
  1277
paulson@4063
  1278
in
wenzelm@4284
  1279
wenzelm@12346
  1280
fun gensym pre = pre ^ (#1(newid (!seedr), inc seedr));
paulson@2003
  1281
paulson@4063
  1282
end;
paulson@4063
  1283
paulson@4063
  1284
wenzelm@233
  1285
(* lexical scanning *)
clasohm@0
  1286
wenzelm@233
  1287
(*scan a list of characters into "words" composed of "letters" (recognized by
wenzelm@233
  1288
  is_let) and separated by any number of non-"letters"*)
wenzelm@233
  1289
fun scanwords is_let cs =
clasohm@0
  1290
  let fun scan1 [] = []
wenzelm@233
  1291
        | scan1 cs =
wenzelm@233
  1292
            let val (lets, rest) = take_prefix is_let cs
wenzelm@233
  1293
            in implode lets :: scanwords is_let rest end;
wenzelm@233
  1294
  in scan1 (#2 (take_prefix (not o is_let) cs)) end;
clasohm@24
  1295
wenzelm@4212
  1296
wenzelm@16439
  1297
(* stamps and serial numbers *)
wenzelm@16439
  1298
wenzelm@16439
  1299
type stamp = unit ref;
wenzelm@16439
  1300
val stamp: unit -> stamp = ref;
wenzelm@16439
  1301
wenzelm@16439
  1302
type serial = int;
wenzelm@16439
  1303
local val count = ref 0
wenzelm@16439
  1304
in fun serial () = inc count end;
wenzelm@16439
  1305
wenzelm@16535
  1306
wenzelm@16535
  1307
(* generic objects *)
wenzelm@16535
  1308
wenzelm@16535
  1309
(*note that the builtin exception datatype may be extended by new
wenzelm@16535
  1310
  constructors at any time*)
wenzelm@16535
  1311
structure Object = struct type T = exn end;
wenzelm@16535
  1312
clasohm@1364
  1313
end;
clasohm@1364
  1314
wenzelm@15745
  1315
structure BasicLibrary: BASIC_LIBRARY = Library;
wenzelm@15745
  1316
open BasicLibrary;