(***********************************************************************)
(*                                                                     *)
(*                                OCaml                                *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the Q Public License version 1.0.               *)
(*                                                                     *)
(***********************************************************************)

(* Miscellaneous useful types and functions *)

val fatal_error: string -> 'a
val fatal_errorf: ('a, Format.formatter, unit, 'b) format4 -> 'a
exception Fatal_error

val try_finally : (unit -> 'a) -> (unit -> unit) -> 'a;;

val map_end: ('a -> 'b) -> 'a list -> 'b list -> 'b list
        (* [map_end f l t] is [map f l @ t], just more efficient. *)
val map_left_right: ('a -> 'b) -> 'a list -> 'b list
        (* Like [List.map], with guaranteed left-to-right evaluation order *)
val for_all2: ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
        (* Same as [List.for_all] but for a binary predicate.
           In addition, this [for_all2] never fails: given two lists
           with different lengths, it returns false. *)
val replicate_list: 'a -> int -> 'a list
        (* [replicate_list elem n] is the list with [n] elements
           all identical to [elem]. *)
val list_remove: 'a -> 'a list -> 'a list
        (* [list_remove x l] returns a copy of [l] with the first
           element equal to [x] removed. *)
val split_last: 'a list -> 'a list * 'a
        (* Return the last element and the other elements of the given list. *)
val may: ('a -> unit) -> 'a option -> unit
val may_map: ('a -> 'b) -> 'a option -> 'b option

module Stdlib : sig
  module List : sig
    type 'a t = 'a list

    val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
    (** The lexicographic order supported by the provided order.
        There is no constraint on the relative lengths of the lists. *)

    val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
    (** Returns [true] iff the given lists have the same length and content
        with respect to the given equality function. *)

    val filter_map : ('a -> 'b option) -> 'a t -> 'b t
    (** [filter_map f l] applies [f] to every element of [l], filters
        out the [None] elements and returns the list of the arguments of
        the [Some] elements. *)

    val some_if_all_elements_are_some : 'a option t -> 'a t option
    (** If all elements of the given list are [Some _] then [Some xs]
        is returned with the [xs] being the contents of those [Some]s, with
        order preserved.  Otherwise return [None]. *)

    val map2_prefix : ('a -> 'b -> 'c) -> 'a t -> 'b t -> ('c t * 'b t)
    (** [let r1, r2 = map2_prefix f l1 l2]
        If [l1] is of length n and [l2 = h2 @ t2] with h2 of length n,
        r1 is [List.map2 f l1 h1] and r2 is t2. *)

    val split_at : int -> 'a t -> 'a t * 'a t
    (** [split_at n l] returns the pair [before, after] where [before] is
        the [n] first elements of [l] and [after] the remaining ones.
        If [l] has less than [n] elements, raises Invalid_argument. *)
  end

  module Option : sig
    type 'a t = 'a option

    val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool

    val iter : ('a -> unit) -> 'a t -> unit
    val map : ('a -> 'b) -> 'a t -> 'b t
    val fold : ('a -> 'b -> 'b) -> 'a t -> 'b -> 'b
    val value_default : ('a -> 'b) -> default:'b -> 'a t -> 'b
  end

  module String : sig
    type t = string

    val split : t -> on:char -> t list
    (** Splits the given string at every occurrence of the given separator.
        Does not return empty substrings when the separator is repeated or
        present at the start or end of the string. *)
  end
end

val find_in_path: string list -> string -> string
        (* Search a file in a list of directories. *)
val find_in_path_rel: string list -> string -> string
        (* Search a relative file in a list of directories. *)
val find_in_path_uncap: string list -> string -> string
        (* Same, but search also for uncapitalized name, i.e.
           if name is Foo.ml, allow /path/Foo.ml and /path/foo.ml
           to match. *)
val remove_file: string -> unit
        (* Delete the given file if it exists. Never raise an error. *)
val expand_directory: string -> string -> string
        (* [expand_directory alt file] eventually expands a [+] at the
           beginning of file into [alt] (an alternate root directory) *)

val create_hashtable: int -> ('a * 'b) list -> ('a, 'b) Hashtbl.t
        (* Create a hashtable of the given size and fills it with the
           given bindings. *)

val copy_file: in_channel -> out_channel -> unit
        (* [copy_file ic oc] reads the contents of file [ic] and copies
           them to [oc]. It stops when encountering EOF on [ic]. *)
val copy_file_chunk: in_channel -> out_channel -> int -> unit
        (* [copy_file_chunk ic oc n] reads [n] bytes from [ic] and copies
           them to [oc]. It raises [End_of_file] when encountering
           EOF on [ic]. *)
val string_of_file: in_channel -> string
        (* [string_of_file ic] reads the contents of file [ic] and copies
           them to a string. It stops when encountering EOF on [ic]. *)
val log2: int -> int
        (* [log2 n] returns [s] such that [n = 1 lsl s]
           if [n] is a power of 2*)
val align: int -> int -> int
        (* [align n a] rounds [n] upwards to a multiple of [a]
           (a power of 2). *)
val no_overflow_add: int -> int -> bool
        (* [no_overflow_add n1 n2] returns [true] if the computation of
           [n1 + n2] does not overflow. *)
val no_overflow_sub: int -> int -> bool
        (* [no_overflow_add n1 n2] returns [true] if the computation of
           [n1 - n2] does not overflow. *)
val no_overflow_mul: int -> int -> bool
        (* [no_overflow_mul n1 n2] returns [true] if the computation of
           [n1 * n2] does not overflow. *)
val no_overflow_lsl: int -> int -> bool
        (* [no_overflow_lsl n k] returns [true] if the computation of
           [n lsl k] does not overflow. *)

module Int_literal_converter : sig
  val int : string -> int
  val int32 : string -> int32
  val int64 : string -> int64
  val nativeint : string -> nativeint
end

val chop_extension_if_any: string -> string
        (* Like Filename.chop_extension but returns the initial file
           name if it has no extension *)

val chop_extensions: string -> string
        (* Return the given file name without its extensions. The extensions
           is the longest suffix starting with a period and not including
           a directory separator, [.xyz.uvw] for instance.

           Return the given name if it does not contain an extension. *)

val search_substring: string -> string -> int -> int
        (* [search_substring pat str start] returns the position of the first
           occurrence of string [pat] in string [str].  Search starts
           at offset [start] in [str].  Raise [Not_found] if [pat]
           does not occur. *)

val replace_substring: before:string -> after:string -> string -> string
        (* [search_substring ~before ~after str] replaces all
           occurences of [before] with [after] in [str] and returns
           the resulting string. *)

val rev_split_words: string -> string list
        (* [rev_split_words s] splits [s] in blank-separated words, and returns
           the list of words in reverse order. *)

val get_ref: 'a list ref -> 'a list
        (* [get_ref lr] returns the content of the list reference [lr] and reset
           its content to the empty list. *)


val fst3: 'a * 'b * 'c -> 'a
val snd3: 'a * 'b * 'c -> 'b
val thd3: 'a * 'b * 'c -> 'c

val fst4: 'a * 'b * 'c * 'd -> 'a
val snd4: 'a * 'b * 'c * 'd -> 'b
val thd4: 'a * 'b * 'c * 'd -> 'c
val for4: 'a * 'b * 'c * 'd -> 'd

module LongString :
  sig
    type t = bytes array
    val create : int -> t
    val length : t -> int
    val get : t -> int -> char
    val set : t -> int -> char -> unit
    val blit : t -> int -> t -> int -> int -> unit
    val output : out_channel -> t -> int -> int -> unit
    val unsafe_blit_to_bytes : t -> int -> bytes -> int -> int -> unit
    val input_bytes : in_channel -> int -> t
  end

val edit_distance : string -> string -> int -> int option
(** [edit_distance a b cutoff] computes the edit distance between
    strings [a] and [b]. To help efficiency, it uses a cutoff: if the
    distance [d] is smaller than [cutoff], it returns [Some d], else
    [None].

    The distance algorithm currently used is Damerau-Levenshtein: it
    computes the number of insertion, deletion, substitution of
    letters, or swapping of adjacent letters to go from one word to the
    other. The particular algorithm may change in the future.
*)

val spellcheck : string list -> string -> string list
(** [spellcheck env name] takes a list of names [env] that exist in
    the current environment and an erroneous [name], and returns a
    list of suggestions taken from [env], that are close enough to
    [name] that it may be a typo for one of them. *)

val did_you_mean : Format.formatter -> (unit -> string list) -> unit
(** [did_you_mean ppf get_choices] hints that the user may have meant
    one of the option returned by calling [get_choices]. It does nothing
    if the returned list is empty.

    The [unit -> ...] thunking is meant to delay any potentially-slow
    computation (typically computing edit-distance with many things
    from the current environment) to when the hint message is to be
    printed. You should print an understandable error message before
    calling [did_you_mean], so that users get a clear notification of
    the failure even if producing the hint is slow.
*)

val split : string -> char -> string list
(** [String.split string char] splits the string [string] at every char
    [char], and returns the list of sub-strings between the chars.
    [String.concat (String.make 1 c) (String.split s c)] is the identity.
    @since 4.01
 *)

val cut_at : string -> char -> string * string
(** [String.cut_at s c] returns a pair containing the sub-string before
   the first occurrence of [c] in [s], and the sub-string after the
   first occurrence of [c] in [s].
   [let (before, after) = String.cut_at s c in
    before ^ String.make 1 c ^ after] is the identity if [s] contains [c].

   Raise [Not_found] if the character does not appear in the string
   @since 4.01
*)


module StringSet: Set.S with type elt = string
module StringMap: Map.S with type key = string
(* TODO: replace all custom instantiations of StringSet/StringMap in various
   compiler modules with this one. *)

(* Color handling *)
module Color : sig
  type color =
    | Black
    | Red
    | Green
    | Yellow
    | Blue
    | Magenta
    | Cyan
    | White
  ;;

  type style =
    | FG of color (* foreground *)
    | BG of color (* background *)
    | Bold
    | Reset

  val ansi_of_style_l : style list -> string
  (* ANSI escape sequence for the given style *)

  type styles = {
    error: style list;
    warning: style list;
    loc: style list;
  }

  val default_styles: styles
  val get_styles: unit -> styles
  val set_styles: styles -> unit

  type setting = Auto | Always | Never

  val setup : setting -> unit
  (* [setup opt] will enable or disable color handling on standard formatters
     according to the value of color setting [opt].
     Only the first call to this function has an effect. *)

  val set_color_tag_handling : Format.formatter -> unit
  (* adds functions to support color tags to the given formatter. *)
end

val normalise_eol : string -> string
(** [normalise_eol s] returns a fresh copy of [s] with any '\r' character which
   appears before a '\n' character removed. Intended for pre-processing text
   which will subsequently be printed on a channel which performs EOL
   transformations (i.e. Windows) but leaves any instances of '\r' which are
   intended for genuine carriage return. *)