src/Pure/library.ML
author haftmann
Sun May 24 15:02:23 2009 +0200 (2009-05-24)
changeset 31250 4b99b1214034
parent 30572 8fbc355100f2
child 31986 a68f88d264f7
permissions -rw-r--r--
funpow_yield; tuned
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(*  Title:      Pure/library.ML
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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, pairs, booleans, lists, integers,
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strings, lists as sets, orders, current directory, misc.
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See also General/basics.ML for the most fundamental concepts.
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*)
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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 undefined: 'a -> 'b
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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 ? : bool * ('a -> 'a) -> 'a -> 'a
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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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  val funpow_yield: int -> ('a -> 'b * 'a) -> 'a -> 'b list * 'a
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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_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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  (*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 change_result: 'a ref -> ('a -> 'b * 'a) -> 'b
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  val setmp_noncritical: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
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  val setmp: 'a ref -> 'a -> ('b -> 'c) -> 'b -> 'c
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  val setmp_thread_data: 'a Universal.tag -> 'a -> 'a -> ('b -> 'c) -> 'b -> 'c
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  (*lists*)
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  exception UnequalLengths
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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 yield_singleton: ('a list -> 'c -> 'b list * 'c) -> 'a -> 'c -> 'b * 'c
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  val apply: ('a -> 'a) list -> 'a -> 'a
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  val perhaps_apply: ('a -> 'a option) list -> 'a -> 'a option
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  val perhaps_loop: ('a -> 'a option) -> 'a -> 'a option
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  val foldl1: ('a * 'a -> 'a) -> 'a list -> 'a
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  val foldr1: ('a * 'a -> 'a) -> 'a list -> 'a
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  val flat: 'a list list -> 'a 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 burrow_options: ('a list -> 'b list) -> 'a option list -> 'b option list
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  val burrow_fst: ('a list -> 'b list) -> ('a * 'c) list -> ('b * 'c) 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 maps: ('a -> 'b list) -> 'a list -> '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 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_drop: int -> '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 map_split: ('a -> 'b * 'c) -> 'a list -> 'b list * 'c list
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  val split_list: ('a * 'b) list -> 'a list * 'b list
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  val map_product: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
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  val fold_product: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
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  val multiply: 'a list -> 'a list list -> 'a list list
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  val separate: 'a -> 'a list -> 'a list
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  val surround: 'a -> 'a list -> 'a list
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  val replicate: int -> 'a -> 'a 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 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 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 signed_string_of_int: int -> string
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  val string_of_indexname: string * int -> string
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  val read_radix_int: 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 first_field: string -> string -> (string * string) option
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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 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 match_string: string -> string -> bool
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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 update: ('a * 'a -> bool) -> 'a -> '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 multisets*)
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  val remove1: ('b * 'a -> bool) -> 'b -> 'a list -> 'a list
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  val submultiset: ('a * 'b -> bool) -> 'a list * 'b list -> bool
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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 bool_ord: bool * bool -> 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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  val tag_list: int -> 'a list -> (int * 'a) list
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  val untag_list: (int * 'a) list -> 'a list
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  val order_list: (int * '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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  (*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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  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 foldl_map: ('a * 'b -> 'a * 'c) -> 'a * 'b list -> 'a * 'c list
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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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end;
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structure Library: LIBRARY =
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struct
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(* functions *)
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fun undefined _ = raise Match;
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fun I x = x;
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fun K x = fn _ => x;
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fun curry f x y = f (x, y);
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fun uncurry f (x, y) = f x y;
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(*conditional application*)
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fun b ? f = fn x => if b then f x else x;
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(*composition with multiple args*)
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fun (f oo g) x y = f (g x y);
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fun (f ooo g) x y z = f (g x y z);
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fun (f oooo g) x y z w = f (g x y z w);
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(*function exponentiation: f (... (f x) ...) with n applications of f*)
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fun funpow (0 : int) _ = I
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  | funpow n f = f #> funpow (n - 1) f;
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fun funpow_yield (0 : int) _ x = ([], x)
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  | funpow_yield n f x = x |> f ||>> funpow_yield (n - 1) f |>> op ::;
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(* errors *)
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exception SYS_ERROR of string;
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fun sys_error msg = raise SYS_ERROR msg;
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exception ERROR of string;
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fun error msg = raise ERROR msg;
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fun cat_error "" msg = error msg
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  | cat_error msg1 msg2 = error (msg1 ^ "\n" ^ msg2);
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fun assert_all pred list msg =
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  let
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    fun ass [] = ()
wenzelm@18681
   291
      | ass (x :: xs) = if pred x then ass xs else error (msg x);
wenzelm@18681
   292
  in ass list end;
wenzelm@18681
   293
wenzelm@18681
   294
wenzelm@21395
   295
(* pairs *)
wenzelm@233
   296
wenzelm@233
   297
fun pair x y = (x, y);
wenzelm@233
   298
fun rpair x y = (y, x);
wenzelm@233
   299
wenzelm@233
   300
fun fst (x, y) = x;
wenzelm@233
   301
fun snd (x, y) = y;
wenzelm@233
   302
haftmann@17498
   303
fun eq_fst eq ((x1, _), (x2, _)) = eq (x1, x2);
haftmann@17498
   304
fun eq_snd eq ((_, y1), (_, y2)) = eq (y1, y2);
haftmann@19454
   305
fun eq_pair eqx eqy ((x1, y1), (x2, y2)) = eqx (x1, x2) andalso eqy (y1, y2);
wenzelm@233
   306
wenzelm@233
   307
fun swap (x, y) = (y, x);
wenzelm@233
   308
wenzelm@233
   309
fun apfst f (x, y) = (f x, y);
wenzelm@233
   310
fun apsnd f (x, y) = (x, f y);
wenzelm@4212
   311
fun pairself f (x, y) = (f x, f y);
wenzelm@233
   312
wenzelm@233
   313
wenzelm@21395
   314
(* booleans *)
wenzelm@233
   315
wenzelm@21395
   316
(*polymorphic equality*)
wenzelm@233
   317
fun equal x y = x = y;
wenzelm@233
   318
fun not_equal x y = x <> y;
wenzelm@233
   319
wenzelm@21395
   320
(*combining predicates*)
wenzelm@16721
   321
fun p orf q = fn x => p x orelse q x;
wenzelm@16721
   322
fun p andf q = fn x => p x andalso q x;
wenzelm@233
   323
wenzelm@25752
   324
val exists = List.exists;
wenzelm@25752
   325
val forall = List.all;
clasohm@0
   326
wenzelm@19644
   327
wenzelm@380
   328
(* flags *)
wenzelm@380
   329
wenzelm@380
   330
fun set flag = (flag := true; true);
wenzelm@380
   331
fun reset flag = (flag := false; false);
wenzelm@380
   332
fun toggle flag = (flag := not (! flag); ! flag);
wenzelm@380
   333
wenzelm@9118
   334
fun change r f = r := f (! r);
wenzelm@28157
   335
fun change_result r f = let val (x, y) = f (! r) in r := y; x end;
wenzelm@9118
   336
wenzelm@18712
   337
(*temporarily set flag during execution*)
wenzelm@23932
   338
fun setmp_noncritical flag value f x =
wenzelm@26079
   339
  uninterruptible (fn restore_attributes => fn () =>
wenzelm@26079
   340
    let
wenzelm@26079
   341
      val orig_value = ! flag;
wenzelm@26079
   342
      val _ = flag := value;
wenzelm@26079
   343
      val result = Exn.capture (restore_attributes f) x;
wenzelm@26079
   344
      val _ = flag := orig_value;
wenzelm@26079
   345
    in Exn.release result end) ();
wenzelm@2958
   346
wenzelm@26079
   347
fun setmp flag value f x =
wenzelm@26079
   348
  NAMED_CRITICAL "setmp" (fn () => setmp_noncritical flag value f x);
wenzelm@23932
   349
wenzelm@25797
   350
fun setmp_thread_data tag orig_data data f x =
wenzelm@26079
   351
  uninterruptible (fn restore_attributes => fn () =>
wenzelm@26079
   352
    let
wenzelm@28122
   353
      val _ = Thread.setLocal (tag, data);
wenzelm@26079
   354
      val result = Exn.capture (restore_attributes f) x;
wenzelm@28122
   355
      val _ = Thread.setLocal (tag, orig_data);
wenzelm@26079
   356
    in Exn.release result end) ();
wenzelm@25797
   357
wenzelm@19644
   358
wenzelm@21395
   359
wenzelm@233
   360
(** lists **)
wenzelm@233
   361
skalberg@15570
   362
exception UnequalLengths;
wenzelm@233
   363
wenzelm@5285
   364
fun single x = [x];
wenzelm@233
   365
wenzelm@20882
   366
fun the_single [x] = x
wenzelm@20882
   367
  | the_single _ = raise Empty;
wenzelm@20882
   368
wenzelm@20882
   369
fun singleton f x = the_single (f [x]);
wenzelm@19273
   370
haftmann@25061
   371
fun yield_singleton f x = f [x] #>> the_single;
haftmann@25061
   372
wenzelm@5904
   373
fun apply [] x = x
wenzelm@5904
   374
  | apply (f :: fs) x = apply fs (f x);
wenzelm@5904
   375
wenzelm@25058
   376
fun perhaps_apply funs arg =
wenzelm@25058
   377
  let
wenzelm@25058
   378
    fun app [] res = res
wenzelm@25058
   379
      | app (f :: fs) (changed, x) =
wenzelm@25058
   380
          (case f x of
wenzelm@25058
   381
            NONE => app fs (changed, x)
wenzelm@25058
   382
          | SOME x' => app fs (true, x'));
wenzelm@25058
   383
  in (case app funs (false, arg) of (false, _) => NONE | (true, arg') => SOME arg') end;
wenzelm@25058
   384
wenzelm@25058
   385
fun perhaps_loop f arg =
wenzelm@25058
   386
  let
wenzelm@25058
   387
    fun loop (changed, x) =
wenzelm@25058
   388
      (case f x of
wenzelm@25058
   389
        NONE => (changed, x)
wenzelm@25058
   390
      | SOME x' => loop (true, x'));
wenzelm@25058
   391
  in (case loop (false, arg) of (false, _) => NONE | (true, arg') => SOME arg') end;
wenzelm@25058
   392
wenzelm@233
   393
wenzelm@21395
   394
(* fold -- old versions *)
haftmann@16691
   395
wenzelm@233
   396
(*the following versions of fold are designed to fit nicely with infixes*)
clasohm@0
   397
wenzelm@233
   398
(*  (op @) (e, [x1, ..., xn])  ===>  ((e @ x1) @ x2) ... @ xn
wenzelm@233
   399
    for operators that associate to the left (TAIL RECURSIVE)*)
wenzelm@233
   400
fun foldl (f: 'a * 'b -> 'a) : 'a * 'b list -> 'a =
wenzelm@233
   401
  let fun itl (e, [])  = e
wenzelm@233
   402
        | itl (e, a::l) = itl (f(e, a), l)
wenzelm@233
   403
  in  itl end;
wenzelm@233
   404
wenzelm@233
   405
(*  (op @) ([x1, ..., xn], e)  ===>   x1 @ (x2 ... @ (xn @ e))
wenzelm@233
   406
    for operators that associate to the right (not tail recursive)*)
wenzelm@233
   407
fun foldr f (l, e) =
wenzelm@233
   408
  let fun itr [] = e
wenzelm@233
   409
        | itr (a::l) = f(a, itr l)
wenzelm@233
   410
  in  itr l  end;
wenzelm@233
   411
berghofe@25681
   412
(*  (op @) [x1, ..., xn]  ===>  ((x1 @ x2) @ x3) ... @ xn
berghofe@25681
   413
    for operators that associate to the left (TAIL RECURSIVE)*)
berghofe@25681
   414
fun foldl1 f [] = raise Empty
berghofe@25681
   415
  | foldl1 f (x :: xs) = foldl f (x, xs);
berghofe@25681
   416
wenzelm@233
   417
(*  (op @) [x1, ..., xn]  ===>   x1 @ (x2 ... @ (x[n-1] @ xn))
wenzelm@233
   418
    for n > 0, operators that associate to the right (not tail recursive)*)
paulson@20443
   419
fun foldr1 f [] = raise Empty
wenzelm@20510
   420
  | foldr1 f l =
paulson@20443
   421
      let fun itr [x] = x
wenzelm@20510
   422
            | itr (x::l) = f(x, itr l)
paulson@20443
   423
      in  itr l  end;
wenzelm@233
   424
wenzelm@16705
   425
fun foldl_map f =
wenzelm@16705
   426
  let
wenzelm@16705
   427
    fun fold_aux (x, []) = (x, [])
wenzelm@16705
   428
      | fold_aux (x, y :: ys) =
wenzelm@16705
   429
          let
wenzelm@16705
   430
            val (x', y') = f (x, y);
wenzelm@16705
   431
            val (x'', ys') = fold_aux (x', ys);
wenzelm@16705
   432
          in (x'', y' :: ys') end;
wenzelm@16705
   433
  in fold_aux end;
wenzelm@16705
   434
wenzelm@233
   435
wenzelm@233
   436
(* basic list functions *)
wenzelm@233
   437
wenzelm@20510
   438
fun eq_list eq (list1, list2) =
haftmann@20348
   439
  let
wenzelm@20510
   440
    fun eq_lst (x :: xs, y :: ys) = eq (x, y) andalso eq_lst (xs, ys)
wenzelm@20510
   441
      | eq_lst _ = true;
wenzelm@20510
   442
  in length list1 = length list2 andalso eq_lst (list1, list2) end;
haftmann@20348
   443
wenzelm@19483
   444
fun maps f [] = []
wenzelm@19483
   445
  | maps f (x :: xs) = f x @ maps f xs;
wenzelm@19483
   446
haftmann@25538
   447
val filter = List.filter;
haftmann@25538
   448
fun filter_out f = filter (not o f);
haftmann@25538
   449
val map_filter = List.mapPartial;
haftmann@25538
   450
wenzelm@24593
   451
fun chop (0: int) xs = ([], xs)
wenzelm@23220
   452
  | chop _ [] = ([], [])
wenzelm@23220
   453
  | chop n (x :: xs) = chop (n - 1) xs |>> cons x;
wenzelm@19011
   454
wenzelm@233
   455
(*take the first n elements from a list*)
wenzelm@24593
   456
fun take (n: int, []) = []
wenzelm@233
   457
  | take (n, x :: xs) =
wenzelm@233
   458
      if n > 0 then x :: take (n - 1, xs) else [];
wenzelm@233
   459
wenzelm@233
   460
(*drop the first n elements from a list*)
wenzelm@24593
   461
fun drop (n: int, []) = []
wenzelm@233
   462
  | drop (n, x :: xs) =
wenzelm@233
   463
      if n > 0 then drop (n - 1, xs) else x :: xs;
clasohm@0
   464
nipkow@4713
   465
fun dropwhile P [] = []
nipkow@4713
   466
  | dropwhile P (ys as x::xs) = if P x then dropwhile P xs else ys;
nipkow@4713
   467
wenzelm@233
   468
(*return nth element of a list, where 0 designates the first element;
wenzelm@18461
   469
  raise Subscript if list too short*)
haftmann@18011
   470
fun nth xs i = List.nth (xs, i);
wenzelm@233
   471
wenzelm@18461
   472
fun nth_list xss i = nth xss i handle Subscript => [];
wenzelm@18461
   473
haftmann@18011
   474
fun nth_map 0 f (x :: xs) = f x :: xs
haftmann@18011
   475
  | nth_map n f (x :: xs) = x :: nth_map (n - 1) f xs
wenzelm@24593
   476
  | nth_map (_: int) _ [] = raise Subscript;
wenzelm@11773
   477
haftmann@24846
   478
fun nth_drop n xs =
haftmann@24846
   479
  List.take (xs, n) @ List.drop (xs, n + 1);
haftmann@24846
   480
haftmann@18514
   481
fun map_index f =
haftmann@18514
   482
  let
wenzelm@24593
   483
    fun mapp (_: int) [] = []
wenzelm@24593
   484
      | mapp i (x :: xs) = f (i, x) :: mapp (i + 1) xs
haftmann@18514
   485
  in mapp 0 end;
haftmann@18514
   486
haftmann@21118
   487
fun fold_index f =
haftmann@21118
   488
  let
wenzelm@24593
   489
    fun fold_aux (_: int) [] y = y
wenzelm@24593
   490
      | fold_aux i (x :: xs) y = fold_aux (i + 1) xs (f (i, x) y);
haftmann@21118
   491
  in fold_aux 0 end;
haftmann@21118
   492
skalberg@15570
   493
val last_elem = List.last;
wenzelm@233
   494
wenzelm@3762
   495
(*rear decomposition*)
skalberg@15570
   496
fun split_last [] = raise Empty
wenzelm@3762
   497
  | split_last [x] = ([], x)
wenzelm@3762
   498
  | split_last (x :: xs) = apfst (cons x) (split_last xs);
wenzelm@3762
   499
ballarin@29209
   500
(*find position of first element satisfying a predicate*)
wenzelm@4212
   501
fun find_index pred =
wenzelm@24593
   502
  let fun find (_: int) [] = ~1
wenzelm@4212
   503
        | find n (x :: xs) = if pred x then n else find (n + 1) xs;
wenzelm@4212
   504
  in find 0 end;
wenzelm@3762
   505
wenzelm@4224
   506
fun find_index_eq x = find_index (equal x);
wenzelm@4212
   507
wenzelm@4212
   508
(*find first element satisfying predicate*)
paulson@22593
   509
val find_first = List.find;
wenzelm@233
   510
wenzelm@4916
   511
(*get first element by lookup function*)
skalberg@15531
   512
fun get_first _ [] = NONE
wenzelm@4916
   513
  | get_first f (x :: xs) =
wenzelm@4916
   514
      (case f x of
skalberg@15531
   515
        NONE => get_first f xs
wenzelm@4916
   516
      | some => some);
wenzelm@4916
   517
haftmann@19233
   518
fun get_index f =
haftmann@19233
   519
  let
wenzelm@24593
   520
    fun get (_: int) [] = NONE
wenzelm@19461
   521
      | get i (x :: xs) =
haftmann@19233
   522
          case f x
wenzelm@19461
   523
           of NONE => get (i + 1) xs
haftmann@19233
   524
            | SOME y => SOME (i, y)
haftmann@19233
   525
  in get 0 end;
haftmann@19233
   526
skalberg@15531
   527
val flat = List.concat;
wenzelm@233
   528
wenzelm@12136
   529
fun unflat (xs :: xss) ys =
wenzelm@19424
   530
      let val (ps, qs) = chop (length xs) ys
nipkow@13629
   531
      in ps :: unflat xss qs end
wenzelm@12136
   532
  | unflat [] [] = []
skalberg@15570
   533
  | unflat _ _ = raise UnequalLengths;
wenzelm@12136
   534
wenzelm@21479
   535
fun burrow f xss = unflat xss (f (flat xss));
haftmann@18359
   536
wenzelm@24864
   537
fun burrow_options f os = map (try hd) (burrow f (map the_list os));
wenzelm@24864
   538
haftmann@18549
   539
fun fold_burrow f xss s =
haftmann@18549
   540
  apfst (unflat xss) (f (flat xss) s);
haftmann@18359
   541
wenzelm@233
   542
(*separate s [x1, x2, ..., xn]  ===>  [x1, s, x2, s, ..., s, xn]*)
wenzelm@233
   543
fun separate s (x :: (xs as _ :: _)) = x :: s :: separate s xs
wenzelm@233
   544
  | separate _ xs = xs;
wenzelm@233
   545
wenzelm@25980
   546
fun surround s (x :: xs) = s :: x :: surround s xs
wenzelm@25980
   547
  | surround s [] = [s];
wenzelm@25980
   548
wenzelm@233
   549
(*make the list [x, x, ..., x] of length n*)
wenzelm@24593
   550
fun replicate (n: int) x =
wenzelm@233
   551
  let fun rep (0, xs) = xs
wenzelm@233
   552
        | rep (n, xs) = rep (n - 1, x :: xs)
wenzelm@233
   553
  in
skalberg@15570
   554
    if n < 0 then raise Subscript
wenzelm@233
   555
    else rep (n, [])
wenzelm@233
   556
  end;
wenzelm@233
   557
wenzelm@4248
   558
(*multiply [a, b, c, ...] * [xs, ys, zs, ...]*)
wenzelm@18148
   559
fun multiply [] _ = []
wenzelm@18148
   560
  | multiply (x :: xs) yss = map (cons x) yss @ multiply xs yss;
wenzelm@4248
   561
wenzelm@25549
   562
(* direct product *)
wenzelm@25549
   563
haftmann@25538
   564
fun map_product f _ [] = []
haftmann@25538
   565
  | map_product f [] _ = []
haftmann@25538
   566
  | map_product f (x :: xs) ys = map (f x) ys @ map_product f xs ys;
wenzelm@233
   567
haftmann@25538
   568
fun fold_product f _ [] z = z
haftmann@25538
   569
  | fold_product f [] _ z = z
haftmann@25538
   570
  | fold_product f (x :: xs) ys z = z |> fold (f x) ys |> fold_product f xs ys;
wenzelm@233
   571
wenzelm@25549
   572
wenzelm@25549
   573
(* lists of pairs *)
wenzelm@233
   574
skalberg@15570
   575
exception UnequalLengths;
skalberg@15570
   576
haftmann@18330
   577
fun map2 _ [] [] = []
haftmann@18330
   578
  | map2 f (x :: xs) (y :: ys) = f x y :: map2 f xs ys
haftmann@18330
   579
  | map2 _ _ _ = raise UnequalLengths;
wenzelm@380
   580
wenzelm@23220
   581
fun fold2 f [] [] z = z
wenzelm@23220
   582
  | fold2 f (x :: xs) (y :: ys) z = fold2 f xs ys (f x y z)
wenzelm@23220
   583
  | fold2 f _ _ _ = raise UnequalLengths;
wenzelm@380
   584
haftmann@25943
   585
fun map_split f [] = ([], [])
haftmann@25943
   586
  | map_split f (x :: xs) =
haftmann@25943
   587
      let
haftmann@25943
   588
        val (y, w) = f x;
haftmann@25943
   589
        val (ys, ws) = map_split f xs;
haftmann@25943
   590
      in (y :: ys, w :: ws) end;
haftmann@25943
   591
wenzelm@19799
   592
fun zip_options (x :: xs) (SOME y :: ys) = (x, y) :: zip_options xs ys
wenzelm@19799
   593
  | zip_options (_ :: xs) (NONE :: ys) = zip_options xs ys
wenzelm@19799
   594
  | zip_options _ [] = []
wenzelm@19799
   595
  | zip_options [] _ = raise UnequalLengths;
wenzelm@4956
   596
wenzelm@233
   597
(*combine two lists forming a list of pairs:
wenzelm@233
   598
  [x1, ..., xn] ~~ [y1, ..., yn]  ===>  [(x1, y1), ..., (xn, yn)]*)
wenzelm@233
   599
fun [] ~~ [] = []
wenzelm@233
   600
  | (x :: xs) ~~ (y :: ys) = (x, y) :: (xs ~~ ys)
skalberg@15570
   601
  | _ ~~ _ = raise UnequalLengths;
wenzelm@233
   602
wenzelm@233
   603
(*inverse of ~~; the old 'split':
wenzelm@233
   604
  [(x1, y1), ..., (xn, yn)]  ===>  ([x1, ..., xn], [y1, ..., yn])*)
skalberg@15570
   605
val split_list = ListPair.unzip;
wenzelm@233
   606
haftmann@28347
   607
fun burrow_fst f xs = split_list xs |>> f |> op ~~;
haftmann@28347
   608
wenzelm@233
   609
wenzelm@233
   610
(* prefixes, suffixes *)
wenzelm@233
   611
haftmann@18441
   612
fun is_prefix _ [] _ = true
haftmann@18441
   613
  | is_prefix eq (x :: xs) (y :: ys) = eq (x, y) andalso is_prefix eq xs ys
haftmann@18441
   614
  | is_prefix eq _ _ = false;
wenzelm@233
   615
wenzelm@233
   616
(* [x1, ..., xi, ..., xn]  --->  ([x1, ..., x(i-1)], [xi, ..., xn])
wenzelm@233
   617
   where xi is the first element that does not satisfy the predicate*)
wenzelm@233
   618
fun take_prefix (pred : 'a -> bool)  (xs: 'a list) : 'a list * 'a list =
wenzelm@233
   619
  let fun take (rxs, []) = (rev rxs, [])
wenzelm@255
   620
        | take (rxs, x :: xs) =
wenzelm@255
   621
            if  pred x  then  take(x :: rxs, xs)  else  (rev rxs, x :: xs)
wenzelm@233
   622
  in  take([], xs)  end;
wenzelm@233
   623
haftmann@20108
   624
fun chop_prefix eq ([], ys) = ([], ([], ys))
haftmann@20108
   625
  | chop_prefix eq (xs, []) = ([], (xs, []))
wenzelm@23220
   626
  | chop_prefix eq (xs as x :: xs', ys as y :: ys') =
haftmann@20108
   627
      if eq (x, y) then
haftmann@20108
   628
        let val (ps', xys'') = chop_prefix eq (xs', ys')
wenzelm@23220
   629
        in (x :: ps', xys'') end
haftmann@20108
   630
      else ([], (xs, ys));
haftmann@20108
   631
wenzelm@233
   632
(* [x1, ..., xi, ..., xn]  --->  ([x1, ..., xi], [x(i+1), ..., xn])
wenzelm@233
   633
   where xi is the last element that does not satisfy the predicate*)
wenzelm@233
   634
fun take_suffix _ [] = ([], [])
wenzelm@233
   635
  | take_suffix pred (x :: xs) =
wenzelm@233
   636
      (case take_suffix pred xs of
wenzelm@233
   637
        ([], sffx) => if pred x then ([], x :: sffx) else ([x], sffx)
wenzelm@233
   638
      | (prfx, sffx) => (x :: prfx, sffx));
wenzelm@233
   639
wenzelm@12249
   640
fun prefixes1 [] = []
wenzelm@12249
   641
  | prefixes1 (x :: xs) = map (cons x) ([] :: prefixes1 xs);
wenzelm@12249
   642
wenzelm@19011
   643
fun prefixes xs = [] :: prefixes1 xs;
wenzelm@19011
   644
wenzelm@12249
   645
fun suffixes1 xs = map rev (prefixes1 (rev xs));
wenzelm@19011
   646
fun suffixes xs = [] :: suffixes1 xs;
wenzelm@233
   647
wenzelm@23220
   648
wenzelm@23220
   649
wenzelm@233
   650
(** integers **)
wenzelm@233
   651
wenzelm@24593
   652
fun inc i = (i := ! i + (1: int); ! i);
wenzelm@24593
   653
fun dec i = (i := ! i - (1: int); ! i);
wenzelm@233
   654
wenzelm@233
   655
wenzelm@233
   656
(* lists of integers *)
wenzelm@233
   657
wenzelm@233
   658
(*make the list [from, from + 1, ..., to]*)
wenzelm@24593
   659
fun ((i: int) upto j) =
wenzelm@21859
   660
  if i > j then [] else i :: (i + 1 upto j);
wenzelm@233
   661
wenzelm@233
   662
(*make the list [from, from - 1, ..., to]*)
wenzelm@24593
   663
fun ((i: int) downto j) =
wenzelm@21859
   664
  if i < j then [] else i :: (i - 1 downto j);
wenzelm@233
   665
wenzelm@233
   666
wenzelm@233
   667
(* convert integers to strings *)
wenzelm@233
   668
wenzelm@233
   669
(*expand the number in the given base;
wenzelm@233
   670
  example: radixpand (2, 8) gives [1, 0, 0, 0]*)
wenzelm@233
   671
fun radixpand (base, num) : int list =
wenzelm@233
   672
  let
wenzelm@233
   673
    fun radix (n, tail) =
wenzelm@233
   674
      if n < base then n :: tail
wenzelm@233
   675
      else radix (n div base, (n mod base) :: tail)
wenzelm@233
   676
  in radix (num, []) end;
wenzelm@233
   677
wenzelm@233
   678
(*expands a number into a string of characters starting from "zerochar";
wenzelm@233
   679
  example: radixstring (2, "0", 8) gives "1000"*)
wenzelm@233
   680
fun radixstring (base, zerochar, num) =
wenzelm@233
   681
  let val offset = ord zerochar;
wenzelm@233
   682
      fun chrof n = chr (offset + n)
wenzelm@233
   683
  in implode (map chrof (radixpand (base, num))) end;
wenzelm@233
   684
wenzelm@233
   685
paulson@3407
   686
val string_of_int = Int.toString;
wenzelm@233
   687
wenzelm@21942
   688
fun signed_string_of_int i =
wenzelm@21942
   689
  if i < 0 then "-" ^ string_of_int (~ i) else string_of_int i;
wenzelm@21942
   690
wenzelm@23220
   691
fun string_of_indexname (a, 0) = a
wenzelm@23220
   692
  | string_of_indexname (a, i) = a ^ "_" ^ string_of_int i;
wenzelm@233
   693
wenzelm@233
   694
wenzelm@14826
   695
(* read integers *)
wenzelm@14826
   696
wenzelm@24630
   697
fun read_radix_int radix cs =
wenzelm@20095
   698
  let
wenzelm@20095
   699
    val zero = ord "0";
wenzelm@20095
   700
    val limit = zero + radix;
wenzelm@20095
   701
    fun scan (num, []) = (num, [])
wenzelm@20095
   702
      | scan (num, c :: cs) =
wenzelm@20095
   703
        if zero <= ord c andalso ord c < limit then
wenzelm@24630
   704
          scan (radix * num + (ord c - zero), cs)
wenzelm@20095
   705
        else (num, c :: cs);
wenzelm@24630
   706
  in scan (0, cs) end;
wenzelm@14826
   707
wenzelm@24630
   708
val read_int = read_radix_int 10;
wenzelm@14826
   709
wenzelm@24630
   710
fun oct_char s = chr (#1 (read_radix_int 8 (explode s)));
wenzelm@14826
   711
wenzelm@14826
   712
wenzelm@14826
   713
wenzelm@233
   714
(** strings **)
wenzelm@233
   715
wenzelm@16188
   716
(* functions tuned for strings, avoiding explode *)
wenzelm@6312
   717
haftmann@18011
   718
fun nth_string str i =
wenzelm@6959
   719
  (case try String.substring (str, i, 1) of
skalberg@15531
   720
    SOME s => s
skalberg@15570
   721
  | NONE => raise Subscript);
wenzelm@6312
   722
wenzelm@16188
   723
fun fold_string f str x0 =
wenzelm@6282
   724
  let
wenzelm@6282
   725
    val n = size str;
wenzelm@16188
   726
    fun iter (x, i) =
wenzelm@16188
   727
      if i < n then iter (f (String.substring (str, i, 1)) x, i + 1) else x;
wenzelm@16188
   728
  in iter (x0, 0) end;
wenzelm@6282
   729
wenzelm@14968
   730
fun exists_string pred str =
wenzelm@14968
   731
  let
wenzelm@14968
   732
    val n = size str;
wenzelm@14968
   733
    fun ex i = i < n andalso (pred (String.substring (str, i, 1)) orelse ex (i + 1));
wenzelm@14968
   734
  in ex 0 end;
wenzelm@6312
   735
wenzelm@16188
   736
fun forall_string pred = not o exists_string (not o pred);
wenzelm@16188
   737
wenzelm@28025
   738
fun first_field sep str =
wenzelm@28022
   739
  let
wenzelm@28025
   740
    val n = size sep;
wenzelm@28022
   741
    val len = size str;
wenzelm@28022
   742
    fun find i =
wenzelm@28022
   743
      if i + n > len then NONE
wenzelm@28025
   744
      else if String.substring (str, i, n) = sep then SOME i
wenzelm@28022
   745
      else find (i + 1);
wenzelm@28025
   746
  in
wenzelm@28025
   747
    (case find 0 of
wenzelm@28025
   748
      NONE => NONE
wenzelm@28025
   749
    | SOME i => SOME (String.substring (str, 0, i), String.extract (str, i + n, NONE)))
wenzelm@28025
   750
  end;
wenzelm@28022
   751
lcp@512
   752
(*enclose in brackets*)
lcp@512
   753
fun enclose lpar rpar str = lpar ^ str ^ rpar;
wenzelm@6642
   754
fun unenclose str = String.substring (str, 1, size str - 2);
wenzelm@255
   755
wenzelm@233
   756
(*simple quoting (does not escape special chars)*)
lcp@512
   757
val quote = enclose "\"" "\"";
wenzelm@233
   758
wenzelm@4212
   759
(*space_implode "..." (explode "hello") = "h...e...l...l...o"*)
wenzelm@233
   760
fun space_implode a bs = implode (separate a bs);
wenzelm@233
   761
wenzelm@255
   762
val commas = space_implode ", ";
wenzelm@380
   763
val commas_quote = commas o map quote;
wenzelm@255
   764
wenzelm@233
   765
(*concatenate messages, one per line, into a string*)
wenzelm@255
   766
val cat_lines = space_implode "\n";
wenzelm@233
   767
wenzelm@4212
   768
(*space_explode "." "h.e..l.lo" = ["h", "e", "", "l", "lo"]*)
wenzelm@3832
   769
fun space_explode _ "" = []
paulson@21899
   770
  | space_explode sep s = String.fields (fn c => str c = sep) s;
wenzelm@3832
   771
wenzelm@3832
   772
val split_lines = space_explode "\n";
wenzelm@3832
   773
wenzelm@14826
   774
fun prefix_lines "" txt = txt
wenzelm@14826
   775
  | prefix_lines prfx txt = txt |> split_lines |> map (fn s => prfx ^ s) |> cat_lines;
wenzelm@14826
   776
wenzelm@18681
   777
fun prefix prfx s = prfx ^ s;
wenzelm@16188
   778
fun suffix sffx s = s ^ sffx;
wenzelm@5285
   779
wenzelm@18681
   780
fun unprefix prfx s =
wenzelm@18681
   781
  if String.isPrefix prfx s then String.substring (s, size prfx, size s - size prfx)
wenzelm@18681
   782
  else raise Fail "unprefix";
wenzelm@18681
   783
wenzelm@16188
   784
fun unsuffix sffx s =
wenzelm@17061
   785
  if String.isSuffix sffx s then String.substring (s, 0, size s - size sffx)
wenzelm@17061
   786
  else raise Fail "unsuffix";
wenzelm@5285
   787
wenzelm@24593
   788
fun replicate_string (0: int) _ = ""
wenzelm@10951
   789
  | replicate_string 1 a = a
wenzelm@10951
   790
  | replicate_string k a =
wenzelm@10951
   791
      if k mod 2 = 0 then replicate_string (k div 2) (a ^ a)
wenzelm@10951
   792
      else replicate_string (k div 2) (a ^ a) ^ a;
wenzelm@10951
   793
haftmann@31250
   794
fun translate_string f = String.translate (f o String.str);
haftmann@31250
   795
kleing@29882
   796
(*crude matching of str against simple glob pat*)
kleing@29882
   797
fun match_string pat str =
kleing@29882
   798
  let
kleing@29882
   799
    fun match [] _ = true
kleing@29882
   800
      | match (p :: ps) s =
kleing@29882
   801
          size p <= size s andalso
kleing@29882
   802
            (case try (unprefix p) s of
kleing@29882
   803
              SOME s' => match ps s'
kleing@29882
   804
            | NONE => match (p :: ps) (String.substring (s, 1, size s - 1)));
kleing@29882
   805
  in match (space_explode "*" pat) str end;
wenzelm@23220
   806
wenzelm@16492
   807
(** lists as sets -- see also Pure/General/ord_list.ML **)
wenzelm@233
   808
wenzelm@26439
   809
(* canonical operations *)
wenzelm@26439
   810
wenzelm@18923
   811
fun member eq list x =
wenzelm@18923
   812
  let
wenzelm@18923
   813
    fun memb [] = false
wenzelm@18923
   814
      | memb (y :: ys) = eq (x, y) orelse memb ys;
wenzelm@18923
   815
  in memb list end;
berghofe@1576
   816
wenzelm@18923
   817
fun insert eq x xs = if member eq xs x then xs else x :: xs;
wenzelm@18923
   818
fun remove eq x xs = if member eq xs x then filter_out (fn y => eq (x, y)) xs else xs;
wenzelm@24049
   819
fun update eq x xs = cons x (remove eq x xs);
wenzelm@233
   820
wenzelm@19301
   821
fun subtract eq = fold (remove eq);
wenzelm@19301
   822
wenzelm@30572
   823
fun merge eq (xs, ys) =
wenzelm@30572
   824
  if pointer_eq (xs, ys) then xs
wenzelm@30572
   825
  else if null xs then ys
wenzelm@30572
   826
  else fold_rev (insert eq) ys xs;
clasohm@0
   827
wenzelm@26439
   828
wenzelm@26439
   829
(* old-style infixes *)
wenzelm@26439
   830
wenzelm@18923
   831
fun x mem xs = member (op =) xs x;
wenzelm@18923
   832
fun (x: int) mem_int xs = member (op =) xs x;
wenzelm@18923
   833
fun (x: string) mem_string xs = member (op =) xs x;
berghofe@1576
   834
wenzelm@233
   835
(*union of sets represented as lists: no repetitions*)
wenzelm@233
   836
fun xs union [] = xs
wenzelm@233
   837
  | [] union ys = ys
haftmann@20854
   838
  | (x :: xs) union ys = xs union (insert (op =) x ys);
clasohm@0
   839
paulson@2175
   840
(*union of sets, optimized version for ints*)
berghofe@1576
   841
fun (xs:int list) union_int [] = xs
berghofe@1576
   842
  | [] union_int ys = ys
haftmann@20854
   843
  | (x :: xs) union_int ys = xs union_int (insert (op =) x ys);
berghofe@1576
   844
paulson@2175
   845
(*union of sets, optimized version for strings*)
berghofe@1576
   846
fun (xs:string list) union_string [] = xs
berghofe@1576
   847
  | [] union_string ys = ys
haftmann@20854
   848
  | (x :: xs) union_string ys = xs union_string (insert (op =) x ys);
berghofe@1576
   849
clasohm@0
   850
(*generalized union*)
wenzelm@233
   851
fun gen_union eq (xs, []) = xs
wenzelm@233
   852
  | gen_union eq ([], ys) = ys
wenzelm@18923
   853
  | gen_union eq (x :: xs, ys) = gen_union eq (xs, insert eq x ys);
wenzelm@233
   854
wenzelm@233
   855
wenzelm@233
   856
(*intersection*)
wenzelm@233
   857
fun [] inter ys = []
wenzelm@233
   858
  | (x :: xs) inter ys =
wenzelm@233
   859
      if x mem ys then x :: (xs inter ys) else xs inter ys;
wenzelm@233
   860
paulson@2175
   861
(*intersection, optimized version for ints*)
berghofe@1576
   862
fun ([]:int list) inter_int ys = []
berghofe@1576
   863
  | (x :: xs) inter_int ys =
berghofe@1576
   864
      if x mem_int ys then x :: (xs inter_int ys) else xs inter_int ys;
berghofe@1576
   865
paulson@2175
   866
(*intersection, optimized version for strings *)
berghofe@1576
   867
fun ([]:string list) inter_string ys = []
berghofe@1576
   868
  | (x :: xs) inter_string ys =
berghofe@1576
   869
      if x mem_string ys then x :: (xs inter_string ys) else xs inter_string ys;
berghofe@1576
   870
paulson@7090
   871
(*generalized intersection*)
paulson@7090
   872
fun gen_inter eq ([], ys) = []
wenzelm@12284
   873
  | gen_inter eq (x::xs, ys) =
wenzelm@18923
   874
      if member eq ys x then x :: gen_inter eq (xs, ys)
wenzelm@18923
   875
      else gen_inter eq (xs, ys);
paulson@7090
   876
wenzelm@233
   877
wenzelm@233
   878
(*subset*)
wenzelm@233
   879
fun [] subset ys = true
wenzelm@233
   880
  | (x :: xs) subset ys = x mem ys andalso xs subset ys;
wenzelm@233
   881
paulson@2175
   882
(*subset, optimized version for ints*)
wenzelm@16439
   883
fun ([]: int list) subset_int ys = true
berghofe@1576
   884
  | (x :: xs) subset_int ys = x mem_int ys andalso xs subset_int ys;
berghofe@1576
   885
paulson@2175
   886
(*subset, optimized version for strings*)
wenzelm@16439
   887
fun ([]: string list) subset_string ys = true
berghofe@1576
   888
  | (x :: xs) subset_string ys = x mem_string ys andalso xs subset_string ys;
berghofe@1576
   889
wenzelm@4363
   890
(*set equality*)
wenzelm@4363
   891
fun eq_set (xs, ys) =
wenzelm@4363
   892
  xs = ys orelse (xs subset ys andalso ys subset xs);
wenzelm@4363
   893
paulson@2182
   894
(*set equality for strings*)
wenzelm@16439
   895
fun eq_set_string ((xs: string list), ys) =
berghofe@1576
   896
  xs = ys orelse (xs subset_string ys andalso ys subset_string xs);
berghofe@1576
   897
wenzelm@18923
   898
fun gen_subset eq (xs, ys) = forall (member eq ys) xs;
paulson@2182
   899
wenzelm@19301
   900
fun gen_eq_set eq (xs, ys) =
haftmann@20348
   901
  eq_list eq (xs, ys) orelse
wenzelm@19301
   902
    (gen_subset eq (xs, ys) andalso gen_subset (eq o swap) (ys, xs));
wenzelm@19301
   903
wenzelm@265
   904
wenzelm@233
   905
(*removing an element from a list WITHOUT duplicates*)
wenzelm@233
   906
fun (y :: ys) \ x = if x = y then ys else y :: (ys \ x)
wenzelm@233
   907
  | [] \ x = [];
paulson@2243
   908
fun ys \\ xs = foldl (op \) (ys,xs);
clasohm@0
   909
wenzelm@233
   910
wenzelm@233
   911
(*makes a list of the distinct members of the input; preserves order, takes
wenzelm@233
   912
  first of equal elements*)
wenzelm@19046
   913
fun distinct eq lst =
wenzelm@233
   914
  let
wenzelm@233
   915
    fun dist (rev_seen, []) = rev rev_seen
wenzelm@233
   916
      | dist (rev_seen, x :: xs) =
wenzelm@18923
   917
          if member eq rev_seen x then dist (rev_seen, xs)
wenzelm@233
   918
          else dist (x :: rev_seen, xs);
wenzelm@19046
   919
  in dist ([], lst) end;
wenzelm@233
   920
wenzelm@255
   921
(*returns a list containing all repeated elements exactly once; preserves
wenzelm@255
   922
  order, takes first of equal elements*)
wenzelm@18966
   923
fun duplicates eq lst =
wenzelm@255
   924
  let
wenzelm@255
   925
    fun dups (rev_dups, []) = rev rev_dups
wenzelm@255
   926
      | dups (rev_dups, x :: xs) =
wenzelm@18923
   927
          if member eq rev_dups x orelse not (member eq xs x) then
wenzelm@255
   928
            dups (rev_dups, xs)
wenzelm@255
   929
          else dups (x :: rev_dups, xs);
wenzelm@18966
   930
  in dups ([], lst) end;
wenzelm@255
   931
wenzelm@16878
   932
fun has_duplicates eq =
wenzelm@16878
   933
  let
wenzelm@16878
   934
    fun dups [] = false
wenzelm@16878
   935
      | dups (x :: xs) = member eq xs x orelse dups xs;
wenzelm@16878
   936
  in dups end;
wenzelm@16878
   937
wenzelm@255
   938
wenzelm@23220
   939
nipkow@22142
   940
(** lists as multisets **)
nipkow@22142
   941
nipkow@22142
   942
fun remove1 _ _ [] = raise Empty
wenzelm@23220
   943
  | remove1 eq y (x::xs) = if eq (y, x) then xs else x :: remove1 eq y xs;
nipkow@22142
   944
wenzelm@23220
   945
fun submultiset _ ([], _)  = true
wenzelm@23220
   946
  | submultiset eq (x :: xs, ys) = member eq ys x andalso submultiset eq (xs, remove1 eq x ys);
wenzelm@233
   947
clasohm@0
   948
clasohm@0
   949
wenzelm@2506
   950
(** orders **)
wenzelm@2506
   951
wenzelm@18966
   952
fun is_equal EQUAL = true
wenzelm@18966
   953
  | is_equal _ = false;
wenzelm@18966
   954
wenzelm@4445
   955
fun rev_order LESS = GREATER
wenzelm@4445
   956
  | rev_order EQUAL = EQUAL
wenzelm@4445
   957
  | rev_order GREATER = LESS;
wenzelm@4445
   958
wenzelm@4479
   959
(*assume rel is a linear strict order*)
wenzelm@4445
   960
fun make_ord rel (x, y) =
wenzelm@4445
   961
  if rel (x, y) then LESS
wenzelm@4445
   962
  else if rel (y, x) then GREATER
wenzelm@4445
   963
  else EQUAL;
wenzelm@4445
   964
wenzelm@25224
   965
fun bool_ord (false, true) = LESS
wenzelm@25224
   966
  | bool_ord (true, false) = GREATER
wenzelm@25224
   967
  | bool_ord _ = EQUAL;
wenzelm@25224
   968
wenzelm@15051
   969
val int_ord = Int.compare;
wenzelm@15051
   970
val string_ord = String.compare;
wenzelm@2506
   971
wenzelm@16676
   972
fun fast_string_ord (s1, s2) =
wenzelm@16676
   973
  (case int_ord (size s1, size s2) of EQUAL => string_ord (s1, s2) | ord => ord);
wenzelm@16676
   974
wenzelm@16492
   975
fun option_ord ord (SOME x, SOME y) = ord (x, y)
wenzelm@16492
   976
  | option_ord _ (NONE, NONE) = EQUAL
wenzelm@16492
   977
  | option_ord _ (NONE, SOME _) = LESS
wenzelm@16492
   978
  | option_ord _ (SOME _, NONE) = GREATER;
wenzelm@16492
   979
wenzelm@4343
   980
(*lexicographic product*)
wenzelm@4343
   981
fun prod_ord a_ord b_ord ((x, y), (x', y')) =
wenzelm@4343
   982
  (case a_ord (x, x') of EQUAL => b_ord (y, y') | ord => ord);
wenzelm@4343
   983
wenzelm@4343
   984
(*dictionary order -- in general NOT well-founded!*)
wenzelm@16984
   985
fun dict_ord elem_ord (x :: xs, y :: ys) =
wenzelm@16984
   986
      (case elem_ord (x, y) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord)
wenzelm@16984
   987
  | dict_ord _ ([], []) = EQUAL
wenzelm@4343
   988
  | dict_ord _ ([], _ :: _) = LESS
wenzelm@16984
   989
  | dict_ord _ (_ :: _, []) = GREATER;
wenzelm@4343
   990
wenzelm@4343
   991
(*lexicographic product of lists*)
wenzelm@4343
   992
fun list_ord elem_ord (xs, ys) =
wenzelm@16676
   993
  (case int_ord (length xs, length ys) of EQUAL => dict_ord elem_ord (xs, ys) | ord => ord);
wenzelm@4343
   994
wenzelm@2506
   995
wenzelm@4621
   996
(* sorting *)
wenzelm@4621
   997
wenzelm@18427
   998
(*quicksort -- stable, i.e. does not reorder equal elements*)
wenzelm@18427
   999
fun quicksort unique ord =
wenzelm@4621
  1000
  let
wenzelm@16878
  1001
    fun qsort [] = []
wenzelm@16878
  1002
      | qsort (xs as [_]) = xs
wenzelm@18427
  1003
      | qsort (xs as [x, y]) =
wenzelm@18427
  1004
          (case ord (x, y) of
wenzelm@18427
  1005
            LESS => xs
wenzelm@18427
  1006
          | EQUAL => if unique then [x] else xs
wenzelm@18427
  1007
          | GREATER => [y, x])
wenzelm@16878
  1008
      | qsort xs =
haftmann@18011
  1009
          let val (lts, eqs, gts) = part (nth xs (length xs div 2)) xs
wenzelm@16878
  1010
          in qsort lts @ eqs @ qsort gts end
wenzelm@4621
  1011
    and part _ [] = ([], [], [])
wenzelm@4621
  1012
      | part pivot (x :: xs) = add (ord (x, pivot)) x (part pivot xs)
wenzelm@4621
  1013
    and add LESS x (lts, eqs, gts) = (x :: lts, eqs, gts)
wenzelm@18427
  1014
      | add EQUAL x (lts, [], gts) = (lts, [x], gts)
wenzelm@18427
  1015
      | add EQUAL x (res as (lts, eqs, gts)) = if unique then res else (lts, x :: eqs, gts)
wenzelm@4621
  1016
      | add GREATER x (lts, eqs, gts) = (lts, eqs, x :: gts);
wenzelm@4621
  1017
  in qsort end;
wenzelm@4621
  1018
wenzelm@18427
  1019
fun sort ord = quicksort false ord;
wenzelm@18427
  1020
fun sort_distinct ord = quicksort true ord;
wenzelm@18427
  1021
wenzelm@4621
  1022
val sort_strings = sort string_ord;
wenzelm@4621
  1023
fun sort_wrt sel xs = sort (string_ord o pairself sel) xs;
wenzelm@4621
  1024
wenzelm@4621
  1025
wenzelm@30558
  1026
(* items tagged by integer index *)
wenzelm@30558
  1027
wenzelm@30558
  1028
(*insert tags*)
wenzelm@30558
  1029
fun tag_list k [] = []
haftmann@30570
  1030
  | tag_list k (x :: xs) = (k:int, x) :: tag_list (k + 1) xs;
wenzelm@30558
  1031
wenzelm@30558
  1032
(*remove tags and suppress duplicates -- list is assumed sorted!*)
wenzelm@30558
  1033
fun untag_list [] = []
wenzelm@30558
  1034
  | untag_list [(k: int, x)] = [x]
wenzelm@30558
  1035
  | untag_list ((k, x) :: (rest as (k', x') :: _)) =
wenzelm@30558
  1036
      if k = k' then untag_list rest
wenzelm@30558
  1037
      else x :: untag_list rest;
wenzelm@30558
  1038
wenzelm@30558
  1039
(*return list elements in original order*)
wenzelm@30558
  1040
fun order_list list = untag_list (sort (int_ord o pairself fst) list);
wenzelm@30558
  1041
wenzelm@30558
  1042
wenzelm@2506
  1043
berghofe@14106
  1044
(** random numbers **)
berghofe@14106
  1045
berghofe@14106
  1046
exception RANDOM;
berghofe@14106
  1047
berghofe@14618
  1048
fun rmod x y = x - y * Real.realFloor (x / y);
berghofe@14106
  1049
berghofe@14106
  1050
local
berghofe@14106
  1051
  val a = 16807.0;
berghofe@14106
  1052
  val m = 2147483647.0;
berghofe@14106
  1053
  val random_seed = ref 1.0;
berghofe@14106
  1054
in
berghofe@14106
  1055
wenzelm@23922
  1056
fun random () = CRITICAL (fn () =>
wenzelm@23922
  1057
  let val r = rmod (a * ! random_seed) m
wenzelm@23922
  1058
  in (random_seed := r; r) end);
berghofe@14106
  1059
berghofe@14106
  1060
end;
berghofe@14106
  1061
berghofe@14106
  1062
fun random_range l h =
berghofe@14106
  1063
  if h < l orelse l < 0 then raise RANDOM
berghofe@14106
  1064
  else l + Real.floor (rmod (random ()) (real (h - l + 1)));
berghofe@14106
  1065
haftmann@18011
  1066
fun one_of xs = nth xs (random_range 0 (length xs - 1));
berghofe@14106
  1067
berghofe@14106
  1068
fun frequency xs =
berghofe@14106
  1069
  let
berghofe@14106
  1070
    val sum = foldl op + (0, map fst xs);
wenzelm@17756
  1071
    fun pick n ((k: int, x) :: xs) =
berghofe@14106
  1072
      if n <= k then x else pick (n - k) xs
berghofe@14106
  1073
  in pick (random_range 1 sum) xs end;
berghofe@14106
  1074
berghofe@14106
  1075
wenzelm@23220
  1076
wenzelm@4621
  1077
(** misc **)
wenzelm@233
  1078
wenzelm@19644
  1079
fun divide_and_conquer decomp x =
wenzelm@19644
  1080
  let val (ys, recomb) = decomp x
wenzelm@19644
  1081
  in recomb (map (divide_and_conquer decomp) ys) end;
wenzelm@19644
  1082
clasohm@0
  1083
wenzelm@233
  1084
(*Partition a list into buckets  [ bi, b(i+1), ..., bj ]
clasohm@0
  1085
   putting x in bk if p(k)(x) holds.  Preserve order of elements if possible.*)
clasohm@0
  1086
fun partition_list p i j =
wenzelm@233
  1087
  let fun part k xs =
wenzelm@233
  1088
            if k>j then
clasohm@0
  1089
              (case xs of [] => []
skalberg@15570
  1090
                         | _ => raise Fail "partition_list")
clasohm@0
  1091
            else
wenzelm@19691
  1092
            let val (ns, rest) = List.partition (p k) xs;
wenzelm@233
  1093
            in  ns :: part(k+1)rest  end
wenzelm@24593
  1094
  in  part (i: int) end;
clasohm@0
  1095
wenzelm@19691
  1096
fun partition_eq (eq:'a * 'a -> bool) =
wenzelm@19691
  1097
  let
wenzelm@19691
  1098
    fun part [] = []
wenzelm@19691
  1099
      | part (x :: ys) =
wenzelm@19691
  1100
          let val (xs, xs') = List.partition (fn y => eq (x, y)) ys
wenzelm@19691
  1101
          in (x::xs)::(part xs') end
wenzelm@19691
  1102
  in part end;
wenzelm@19691
  1103
wenzelm@19691
  1104
clasohm@0
  1105
wenzelm@233
  1106
(* generating identifiers *)
clasohm@0
  1107
paulson@4063
  1108
(** Freshly generated identifiers; supplied prefix MUST start with a letter **)
wenzelm@22369
  1109
local
wenzelm@22369
  1110
(*Maps 0-61 to A-Z, a-z, 0-9; exclude _ or ' to avoid clash with internal/unusual indentifiers*)
wenzelm@22582
  1111
fun gensym_char i =
paulson@22368
  1112
  if i<26 then chr (ord "A" + i)
paulson@22368
  1113
  else if i<52 then chr (ord "a" + i - 26)
wenzelm@22369
  1114
  else chr (ord "0" + i - 52);
paulson@4063
  1115
wenzelm@22369
  1116
val char_vec = Vector.tabulate (62, gensym_char);
wenzelm@22369
  1117
fun newid n = implode (map (fn i => Vector.sub (char_vec, i)) (radixpand (62, n)));
wenzelm@4284
  1118
wenzelm@24593
  1119
val gensym_seed = ref (0: int);
paulson@2003
  1120
wenzelm@22369
  1121
in
wenzelm@24148
  1122
  fun gensym pre = pre ^ newid (NAMED_CRITICAL "gensym" (fn () => inc gensym_seed));
wenzelm@22369
  1123
end;
paulson@4063
  1124
paulson@4063
  1125
wenzelm@16439
  1126
(* stamps and serial numbers *)
wenzelm@16439
  1127
wenzelm@16439
  1128
type stamp = unit ref;
wenzelm@16439
  1129
val stamp: unit -> stamp = ref;
wenzelm@16439
  1130
wenzelm@16439
  1131
type serial = int;
wenzelm@25702
  1132
val serial = Multithreading.serial;
wenzelm@19512
  1133
val serial_string = string_of_int o serial;
wenzelm@19512
  1134
wenzelm@16535
  1135
wenzelm@16535
  1136
(* generic objects *)
wenzelm@16535
  1137
wenzelm@16535
  1138
(*note that the builtin exception datatype may be extended by new
wenzelm@16535
  1139
  constructors at any time*)
wenzelm@16535
  1140
structure Object = struct type T = exn end;
wenzelm@16535
  1141
clasohm@1364
  1142
end;
clasohm@1364
  1143
wenzelm@15745
  1144
structure BasicLibrary: BASIC_LIBRARY = Library;
wenzelm@15745
  1145
open BasicLibrary;