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(*
* ExtPervasives - Additional functions
* Copyright (C) 1996 Xavier Leroy
* 2003 Nicolas Cannasse
* 2007 Zheng Li
* 2008 David Teller
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version,
* with the special exception on linking described in file LICENSE.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*)

(** {6 Additional functions.}

@author Xavier Leroy (Base module)
@author Nicolas Cannasse
@author David Teller
@author Zheng Li
*)

open BatIO

(** The initially opened module.

This module provides the basic operations over the built-in types
(numbers, booleans, strings, exceptions, references, lists, arrays,
input-output channels, ...)

This module is automatically opened at the beginning of each compilation.
All components of this module can therefore be referred by their short
name, without prefixing them by [BatPervasives].

@author Xavier Leroy (Base module)
@author Nicolas Cannasse
@author David Teller
@author Zheng Li
*)

(**/**)
val input_lines : Pervasives.in_channel -> string BatEnum.t
(** Returns an enumeration over lines of an input channel, as read by the
[input_line] function. *)

val input_chars : Pervasives.in_channel -> char BatEnum.t
(** Returns an enumeration over characters of an input channel. *)

val input_list : Pervasives.in_channel -> string list
(** Returns the list of lines read from an input channel. *)

val input_all : Pervasives.in_channel -> string
(** Return the whole contents of an input channel as a single
string. *)
(**/**)


(** {6 String operations}

More string operations are provided in module {!BatString}.
*)

val uppercase : string -> string
(** Return a copy of the argument, with all lowercase letters
translated to uppercase, including accented letters of the ISO
Latin-1 (8859-1) character set. *)

val lowercase : string -> string
(** Return a copy of the argument, with all uppercase letters
translated to lowercase, including accented letters of the ISO
Latin-1 (8859-1) character set. *)


(** {6 String conversion functions}

These are the most common string conversion functions. For
additional string conversion functions, see in the corresponding
module (e.g. for conversion between [int32] and [string],
see module {!Int32}).
*)

val string_of_char : char -> string
(** creates a string from a char. *)

val dump : 'a -> string
(** Attempt to convert a value to a string.

Since types are lost at compile time, the representation might not
match your type. For example, None will be printed 0 since they
share the same runtime representation.

[dump] may fail for ill-formed values, such as obtained from
a faulty C binding or crazy uses of [Obj.set_tag].
*)

val print_any : 'b BatIO.output -> 'a -> unit
(** Attempt to print a value to an output.

Uses [dump] to convert the value to a string and prints that
string to the output.
*)

(** {6 List operations}

More list operations are provided in module {!List}.
*)

val ( @ ) : 'a list -> 'a list -> 'a list
(** List concatenation. *)


(** {6 Input/output}

This section only contains the most common input/output operations.
More operations may be found in modules {!BatIO} and {!File}.
*)

val stdin : input
(** Standard input, as per Unix/Windows conventions (by default, keyboard).

Use this input to read what the user is writing on the keyboard.*)

val stdout: unit output
(** Standard output, as per Unix/Windows conventions (by default, console).

Use this output to display regular messages.*)

val stderr: unit output
(** Standard error output, as per Unix/Windows conventions.

Use this output to display warnings and error messages.*)

val stdnull: unit output
(** An output which discards everything written to it.

Use this output to ignore messages.*)

val flush_all : unit -> unit
(** Write all pending data to output channels, ignore all errors.

It is normally not necessary to call this function, as all pending
data is written when an output channel is closed or when the
program itself terminates, either normally or because of an
uncaught exception. However, this function is useful for
debugging, as it forces pending data to be written immediately.
*)

(** {7 Output functions on standard output} *)


val print_bool : bool -> unit
(** Print a boolean on standard output. *)

val print_guess : 'a BatIO.output -> 'b -> unit
  (** Attempt to print the representation of a runtime value on the
standard output. See remarks for {!dump}. This function is
useful mostly for debugging. As a general rule, it should not be
used in production code.*)

val print_all : input -> unit
  (** Print the contents of an input to the standard output.*)

(** {7 Output functions on standard error} *)

val prerr_bool : bool -> unit
(** Print a boolean to stderr. *)

val prerr_guess : 'a -> unit
  (** Attempt to print the representation of a runtime value on the
error output. See remarks for {!dump}. This function is
useful mostly for debugging.*)

val prerr_all : input -> unit
  (** Print the contents of an input to the error output.*)

(** {7 General output functions} *)

val output_file : filename:string -> text:string -> unit
(** creates a filename, write text into it and close it. *)

val open_out : ?mode:(BatFile.open_out_flag list) ->
               ?perm:BatFile.permission ->
  string -> unit BatIO.output
  (** Open the named file for writing, and return a new output channel
on that file. You will need to close the file once you have
finished using it.

You may use optional argument [mode] to decide whether the
output will overwrite the contents of the file (by default) or
to add things at the end of the file, whether the file should be
created if it does not exist yet (the default) or not, whether
this operation should proceed if the file exists already (the
default) or not, whether the file should be opened as text
(the default) or as binary, and whether the file should be
opened for non-blocking operations.

You may use optional argument [perm] to specify the permissions
of the file, as per Unix conventions. By default, files are created
with default permissions (which depend on your setup).

@raise Sys_error if the file could not be opened. *)

val open_out_bin : string -> unit BatIO.output
  (** Same as {!open_out}, but the file is opened in binary mode, so
that no translation takes place during writes. On operating
systems that do not distinguish between text mode and binary
mode, this function behaves like {!open_out} without any
[mode] or [perm]. *)

val open_out_gen : open_flag list -> int -> string -> unit BatIO.output
  (**
[open_out_gen mode perm filename] opens the named file for writing,
as described above. The extra argument [mode]
specifies the opening mode. The extra argument [perm] specifies
the file permissions, in case the file must be created.

@deprecated Use {!open_out instead}*)

val flush : unit BatIO.output -> unit
  (** Flush the buffer associated with the given output, performing
all pending writes on that channel. Interactive programs must be
careful about flushing standard output and standard error at the
right time. *)



val output_char : unit BatIO.output -> char -> unit
(** Write the character on the given output channel. *)

val output_string : unit BatIO.output -> string -> unit
(** Write the string on the given output channel. *)

val output : unit BatIO.output -> string -> int -> int -> unit
(** [output oc buf pos len] writes [len] characters from string [buf],
starting at offset [pos], to the given output channel [oc].
@raise Invalid_argument if [pos] and [len] do not
designate a valid substring of [buf]. *)

val output_byte : unit BatIO.output -> int -> unit
(** Write one 8-bit integer (as the single character with that code)
on the given output channel. The given integer is taken modulo
256. *)

val output_binary_int : unit BatIO.output -> int -> unit
  (** Write one integer in binary format (4 bytes, big-endian)
on the given output channel.
The given integer is taken modulo 2{^32}.
The only reliable way to read it back is through the
{!Pervasives.input_binary_int} function. The format is compatible across
all machines for a given version of Objective Caml. *)

val output_binary_float : unit BatIO.output -> float -> unit
  (** Write one float in binary format (8 bytes, IEEE 754 double format)
on the given output channel.
The only reliable way to read it back is through the
{!Pervasives.input_binary_float} function. The format is compatible across
all machines for a given version of Objective Caml. *)

val output_value : unit BatIO.output -> 'a -> unit
  (** Write the representation of a structured value of any type
to a channel. Circularities and sharing inside the value
are detected and preserved. The object can be read back,
by the function {!input_value}. See the description of module
{!Marshal} for more information. {!output_value} is equivalent
to {!Marshal.output} with an empty list of flags. *)


val close_out : unit BatIO.output -> unit
  (** Close the given channel, flushing all buffered write operations.
Output functions raise a [Sys_error] exception when they are
applied to a closed output channel, except [close_out] and [flush],
which do nothing when applied to an already closed channel.
@raise Sys_error if the operating
system signals an error when flushing or closing. *)

val close_out_noerr : unit BatIO.output -> unit
  (** Same as [close_out], but ignore all errors. *)

(** {7 General input functions} *)

val input_file : ?bin:bool -> string -> string
(** returns the data of a given filename. *)

val open_in : ?mode:(BatFile.open_in_flag list) ->
  ?perm:BatFile.permission ->
  string -> BatIO.input
(** Open the named file for reading. You will need to close the file once you have
finished using it.

You may use optional argument [mode] to decide whether the opening
should fail if the file doesn't exist yet (by default) or whether
the file should be created if it doesn't exist yet, whether the
opening should fail if the file already exists or not (by
default), whether the file should be read as binary (by default)
or as text, and whether reading should be non-blocking.

You may use optional argument [perm] to specify the permissions of
the file, should it be created, as per Unix conventions. By
default, files are created with default permissions (which depend
on your setup).

@raise Sys_error if the file could not be opened. *)


val open_in_bin : string -> BatIO.input
(** Same as {!Pervasives.open_in}, but the file is opened in binary mode,
so that no translation takes place during reads. On operating
systems that do not distinguish between text mode and binary
mode, this function behaves like {!Pervasives.open_in}. *)

val open_in_gen : open_flag list -> int -> string -> BatIO.input
(** [open_in mode perm filename] opens the named file for reading,
as described above. The extra arguments [mode] and [perm]
specify the opening mode and file permissions.
{!Pervasives.open_in} and {!Pervasives.open_in_bin} are special
cases of this function.

@deprecated Use {!open_in instead}*)

val input_char : BatIO.input -> char
(** Read one character from the given input channel.
@raise End_of_file if there are no more characters to read. *)

val input_line : BatIO.input -> string
(** Read characters from the given input channel, until a
newline character is encountered. Return the string of
all characters read, without the newline character at the end.
@raise End_of_file if the end of the file is reached
at the beginning of line. *)

val input : BatIO.input -> string -> int -> int -> int
(** [input ic buf pos len] reads up to [len] characters from
the given channel [ic], storing them in string [buf], starting at
character number [pos].
It returns the actual number of characters read, between 0 and
[len] (inclusive).
A return value of 0 means that the end of file was reached.
A return value between 0 and [len] exclusive means that
not all requested [len] characters were read, either because
no more characters were available at that time, or because
the implementation found it convenient to do a partial read;
[input] must be called again to read the remaining characters,
if desired. (See also {!Pervasives.really_input} for reading
exactly [len] characters.)
@raise Invalid_argument if [pos] and [len]
do not designate a valid substring of [buf]. *)

val really_input : BatIO.input -> string -> int -> int -> unit
(** [really_input ic buf pos len] reads [len] characters from channel [ic],
storing them in string [buf], starting at character number [pos].
@raise End_of_file if the end of file is reached before [len]
characters have been read.
@raise Invalid_argument if
[pos] and [len] do not designate a valid substring of [buf]. *)

val input_byte : BatIO.input -> int
(** Same as {!Pervasives.input_char}, but return the 8-bit integer representing
the character.
@raise End_of_file if an end of file was reached. *)

val input_binary_int : BatIO.input -> int
(** Read an integer encoded in binary format (4 bytes, big-endian)
from the given input channel. See {!Pervasives.output_binary_int}.
@raise End_of_file if an end of file was reached while reading the
integer. *)

val input_binary_float : BatIO.input -> float
(** Read a float encoded in binary format (8 bytes, IEEE 754 double format)
from the given input channel. See {!Pervasives.output_binary_float}.
@raise End_of_file if an end of file was reached while reading the
float. *)

val input_value : BatIO.input -> 'a
(** Read the representation of a structured value, as produced
by {!output_value}, and return the corresponding value.
This function is identical to {!Marshal.input};
see the description of module {!Marshal} for more information,
in particular concerning the lack of type safety. *)

val close_in : BatIO.input -> unit
  (** Close the given channel. Input functions raise a [Sys_error]
exception when they are applied to a closed input channel,
except [close_in], which does nothing when applied to an already
closed channel.
@raise Sys_error if
the operating system signals an error. *)

val close_in_noerr : BatIO.input -> unit
(** Same as [close_in], but ignore all errors. *)


(**
{6 Fundamental functions and operators}
*)

external identity : 'a -> 'a = "%identity"
(** The identity function. *)

val undefined : ?message:string -> 'a -> 'b
(** The undefined function.

Evaluating [undefined x] always fails and raises an exception
"Undefined". Optional argument [message] permits the
customization of the error message.*)


val ( |> ) : 'a -> ('a -> 'b) -> 'b
(** Function application. [x |> f] is equivalent to [f x].

This operator is commonly used to write a function composition by
order of evaluation (the order used in object-oriented
programming) rather than by inverse order (the order typically
used in functional programming).

For instance, [g (f x)] means "apply [f] to [x], then apply [g] to
the result." The corresponding notation in most object-oriented
programming languages would be somewhere along the lines of [x.f.g
()], or "starting from [x], apply [f], then apply [g]." In OCaml,
operator ( |> ) this latest notation maps to [x |> f |> g], or

This operator may also be useful for composing sequences of
function calls without too many parenthesis. *)


val ( **> ) : ('a -> 'b) -> 'a -> 'b
  (** Function application. [f **> x] is equivalent to [f x].

This operators may be useful for composing sequences of
function calls without too many parenthesis.

{b Note} The name of this operator is not written in stone.
It is bound to change soon.*)

val ( <| ) : ('a -> 'b) -> 'a -> 'b
(** same as [ ( **> ) ] *)

val ( |- ) : ('a -> 'b) -> ('b -> 'c) -> 'a -> 'c
(** Function composition. [f |- g] is [fun x -> g (f x)].
This is also equivalent to applying [<**] twice.*)

val ( -| ) : ('a -> 'b) -> ('c -> 'a) -> 'c -> 'b
(** Function composition. [f -| g] is [fun x -> f (g x)]. Mathematically, this is
operator o.*)

val ( |? ) : 'a option -> 'a -> 'a
(** Like {!BatOption.default}, with the arguments reversed.
[None |? 10] returns [10], while [Some "foo" |? "bar"] returns ["foo"].

{b Note} This operator does not short circuit like [( || )] and [( && )].
Both arguments will be evaluated.

@since 2.0 *)

val flip : ( 'a -> 'b -> 'c ) -> 'b -> 'a -> 'c
  (** Argument flipping.

[flip f x y] is [f y x]. Don't abuse this function, it may shorten considerably
your code but it also has the nasty habit of making it harder to read.*)


val ( *** ) : ('a -> 'b) -> ('c -> 'd) -> 'a * 'c -> 'b * 'd
(** Function pairing.

[f *** g] is [fun (x,y) -> (f x, g y)]. Equivalent to {!Tuple.Tuple2.map}. *)

val ( &&& ) : ('a -> 'b) -> ('a -> 'c) -> 'a -> ('b * 'c)
  (** Applying two functions to the same argument.

[ f &&& g] is [fun x -> (f x, g x)]. *)

val curry : ('a * 'b -> 'c) -> 'a -> 'b -> 'c
(** Convert a function which accepts a pair of arguments into
a function which accepts two arguments.

[curry f] is [fun x y -> f (x,y)]*)

val uncurry : ('a -> 'b -> 'c) -> 'a * 'b -> 'c
  (** Convert a function which accepts a two arguments into a function
which accepts a pair of arguments.

[uncurry f] is [fun (x, y) -> f x y]*)

val const : 'a -> (_ -> 'a)
(** Ignore its second argument.

[const x] is the function which always returns [x].*)

val unique : unit -> int
(** Returns an unique identifier every time it is called.

{b Note} This is thread-safe.*)

val tap : ('a -> unit) -> 'a -> 'a
  (** Allows application of a function in the middle of a pipe
sequence without disturbing the sequence. [x |> tap f]
evaluates to [x], but has the side effect of [f x]. Useful for
debugging. *)

val finally : (unit -> unit) -> ('a -> 'b) -> 'a -> 'b
  (** [finally fend f x] calls [f x] and then [fend()] even if [f x] raised
an exception. *)

val with_dispose : dispose:('a -> unit) -> ('a -> 'b) -> 'a -> 'b
(** [with_dispose dispose f x] invokes [f] on [x], calling [dispose x]
when [f] terminates (either with a return value or an
exception). *)

val forever : ('a -> 'b) -> 'a -> unit
(** [forever f x] invokes [f] on [x] repeatedly (until an exception occurs). *)

val ignore_exceptions : ('a -> 'b) -> 'a -> unit
(** [ignore_exceptions f x] invokes [f] on [x], ignoring both the returned value
and the exceptions that may be raised. *)

val verify_arg : bool -> string -> unit
(** [verify_arg condition message] will raise [Invalid_argument message] if
[condition] is false, otherwise it does nothing.

@since 2.0 *)

val args : unit -> string BatEnum.t
  (** An enumeration of the arguments passed to this program through the command line.

[args ()] is given by the elements of [Sys.argv], minus the first element.*)

(**/**)
val invisible_args : int ref
(** The number of arguments which must never be returned by [args]

Typically, [invisible_args] is [1], to drop the name of the executable. However,
in some circumstances, it may be useful to pretend that some arguments need not
be parsed.
*)
(**/**)


val exe : string
  (** The name of the current executable.

[exe] is given by the first argument of [Sys.argv]*)


(**
{6 Enumerations}

In OCaml Batteries Included, all data structures are enumerable,
which means that they support a number of standard operations,
transformations, etc. The general manner of {i enumerating} the
contents of a data structure is to invoke the [enum] function of
your data structure.

For instance, you may use the {!foreach} loop to apply a function
[f] to all the consecutive elements of a string [s]. For this
purpose, you may write either [foreach (String.enum s) f] or [open
String in foreach (enum s) f]. Either possibility states that you
are enumerating through a character string [s]. Should you prefer
your enumeration to proceed from the end of the string to the
beginning, you may replace {! String.enum} with {!
String.backwards}. Therefore, either [foreach (String.backwards s)
f] or [open String in foreach (backwards s) f] will apply [f]
to all the consecutive elements of string [s], from the last to
the first.

Similarly, you may use {!List.enum} instead of {!String.enum} to
visit the elements of a list in the usual order, or
{!List.backwards} instead of {!String.backwards} to visit them
in the opposite order, or {!Hashtbl.enum} for hash tables, etc.

More operations on enumerations are defined in module {!BatEnum},
including the necessary constructors to make your own structures
enumerable.

The various kinds of loops are detailed further in this documentation.
*)

val foreach: 'a BatEnum.t -> ('a -> unit) -> unit
  (** Imperative loop on an enumeration.

[foreach e f] applies function [f] to each successive element of [e].
For instance, [foreach (1 -- 10) print_int] invokes function [print_int]
on [1], [2], ..., [10], printing [12345678910].

{b Note} This function is one of the many loops available on
enumerations. Other commonly used loops are {!iter} (same usage
scenario as [foreach], but with different notations), {!map}
(convert an enumeration to another enumeration) or {!fold}
(flatten an enumeration by applying an operation to each
element).

*)

(**
{7 General-purpose loops}

{topic loops}

The following functions are the three main general-purpose loops
available in OCaml. By opposition to the loops available in
imperative languages, OCaml loops are regular functions, which
may be passed, composed, currified, etc. In particular, each
of these loops may be considered either as a manner of applying
a function to a data structure or as transforming a function
into another function which will act on a whole data structure.

For instance, if [f] is a function operating on one value, you may
lift this function to operate on all values of an enumeration (and
consequently on all values of any data structure of OCaml Batteries
Included) by applying {!iter}, {!map} or {!fold} to this function.
*)


val iter : ('a -> unit) -> 'a BatEnum.t -> unit
  (** Imperative loop on an enumeration. This loop is typically used
to lift a function with an effect but no meaningful result and
get it to work on enumerations.

If [f] is a function [iter f] is a function which behaves as [f]
but acts upon enumerations rather than individual elements. As
indicated in the type of [iter], [f] must produce values of type
[unit] (i.e. [f] has no meaningful result) the resulting function
produces no meaningful result either.

In other words, [iter f] is a function which, when applied upon
an enumeration [e], calls [f] with each element of [e] in turn.

For instance, [iter f (1 -- 10)] invokes function [f] on [1],
[2], ..., [10] and produces value [()].
*)

val map : ('a -> 'b) -> 'a BatEnum.t -> 'b BatEnum.t
  (** Transformation loop on an enumeration, used to build an enumeration
from another enumeration. This loop is typically used to transform
an enumeration into another enumeration with the same number of
elements, in the same order.

If [f] is a function, [map f e] is a function which behaves as
[f] but acts upon enumerations rather than individual elements --
and builds a new enumeration from the results of each application.

In other words, [map f] is a function which, when applied
upon an enumeration containing elements [e0], [e1], ...,
produces enumeration [f e0], [f e1], ...

For instance, if [odd] is the function which returns [true]
when applied to an odd number or [false] when applied to
an even number, [map odd (1 -- 10)] produces enumeration
[true], [false], [true], ..., [false].

Similarly, if [square] is the function [fun x -> x * x],
[map square (1 -- 10)] produces the enumeration of the
square numbers of all numbers between [1] and [10].
*)


val filter_map : ('a -> 'b option) -> 'a BatEnum.t -> 'b BatEnum.t
  (** Similar to a map, except that you can skip over some items of the
incoming enumeration by returning None instead of Some value.
Think of it as a {!filter} combined with a {!map}.
*)


val reduce : ('a -> 'a -> 'a) -> 'a BatEnum.t -> 'a
  (** Transformation loop on an enumeration, used to build a single value
from an enumeration.

If [f] is a function and [e] is an enumeration, [reduce f e] applies
function [f] to the first two elements of [e], then to the result of this
expression and to the third element of [e], then to the result of this
new expression and to the fourth element of [e]...

In other words, [reduce f e] returns [a0] if [e] contains only
one element [a0], otherwise [f (... (f (f a0) a1) ...) aN] where
[a0,a1..aN] are the elements of [e].

@raise Not_found if [e] is empty.

For instance, if [add] is the function [fun x y -> x + y],
[reduce add] is the function which computes the sum of the
elements of an enumeration -- and doesn't work on empty
enumerations. Therefore, [reduce add (1 -- 10)]
produces result [55].
*)

val fold : ('b -> 'a -> 'b) -> 'b -> 'a BatEnum.t -> 'b
  (** Transformation loop on an enumeration, used to build a single value
from an enumeration. This is the most powerful general-purpose
loop and also the most complex.

If [f] is a function, [fold f v e] applies [f v] to the first
element of [e], then, calling [acc_1] the result of this
operation, applies [f acc_1] to the second element of [e], then,
calling [acc_2] the result of this operation, applies [f acc_2]
to the third element of [e]...

In other words, [fold f v e] returns [v] if [e] is empty,
otherwise [f (... (f (f v a0) a1) ...) aN] where a0,a1..aN are
the elements of [e].

For instance, if [add] is the function [fun x y -> x + y],
[fold add 0] is the function which computes the sum of the
elements of an enumeration. Therefore, [fold add 0 (1 -- 10)]
produces result [55].
*)

val scanl : ('b -> 'a -> 'b) -> 'b -> 'a BatEnum.t -> 'b BatEnum.t
  (** Functional loop on an enumeration, used to build an enumeration
from both an enumeration and an initial value. This function may
be seen as a variant of {!fold} which returns not only the final
result of {!fold} but the enumeration of all the intermediate
results of {!fold}.

If [f] is a function, [scanl f v e] is applies [f v] to the first
element of [e], then, calling [acc_1] the result of this
operation, applies [f acc_1] to the second element of [e], then,
calling [acc_2] the result of this operation, applies [f acc_2]
to the third element of [e]...

For instance, if [add] is the function [fun x y -> x + y],
[scanl add 0] is the function which computes the sum of the
elements of an enumeration. Therefore, [scanl add 0 (1 -- 10)]
produces result the enumeration with elements [0, 1, 3, 6, 10,
15, 21, 28, 36, 45, 55]. *)

val ( /@ ) : 'a BatEnum.t -> ('a -> 'b) -> 'b BatEnum.t

val ( @/ ) : ('a -> 'b) -> 'a BatEnum.t -> 'b BatEnum.t
  (**
Mapping operators.

These operators have the same meaning as function {!map} but are
sometimes more readable than this function, when chaining
several transformations in a row.
*)

val ( //@ ) : 'a BatEnum.t -> ('a -> 'b option) -> 'b BatEnum.t

val ( @// ) : ('a -> 'b option) -> 'a BatEnum.t -> 'b BatEnum.t
  (**
Map combined with filter. Same as {!filter_map}.
*)

(**
{7 Other operations on enumerations}
*)

val exists: ('a -> bool) -> 'a BatEnum.t -> bool
(** [exists f e] returns [true] if there is some [x] in [e] such
that [f x]*)

val for_all: ('a -> bool) -> 'a BatEnum.t -> bool
(** [exists f e] returns [true] if for every [x] in [e], [f x] is true*)



val find : ('a -> bool) -> 'a BatEnum.t -> 'a
  (** [find f e] returns the first element [x] of [e] such that [f x] returns
[true], consuming the enumeration up to and including the
found element, or, raises [Not_found] if no such element exists
in the enumeration, consuming the whole enumeration in the search.

Since [find] consumes a prefix of the enumeration, it can be used several
times on the same enumeration to find the next element.

@raise Not_found if no element in the whole enumeration satisfies the predicate *)

val peek : 'a BatEnum.t -> 'a option
  (** [peek e] returns [None] if [e] is empty or [Some x] where [x] is
the next element of [e]. The element is not removed from the
enumeration. *)

val get : 'a BatEnum.t -> 'a option
  (** [get e] returns [None] if [e] is empty or [Some x] where [x] is
the next element of [e], in which case the element is removed
from the enumeration. *)

val push : 'a BatEnum.t -> 'a -> unit
  (** [push e x] will add [x] at the beginning of [e]. *)

val junk : 'a BatEnum.t -> unit
  (** [junk e] removes the first element from the enumeration, if any. *)

val filter : ('a -> bool) -> 'a BatEnum.t -> 'a BatEnum.t
  (** [filter f e] returns an enumeration over all elements [x] of [e] such
as [f x] returns [true]. *)

val ( // ) : 'a BatEnum.t -> ('a -> bool) -> 'a BatEnum.t
(** Filtering (pronounce this operator name "such that").

For instance, [(1 -- 37) // odd] is the enumeration of all odd
numbers between 1 and 37.*)

val concat : 'a BatEnum.t BatEnum.t -> 'a BatEnum.t
  (** [concat e] returns an enumeration over all elements of all enumerations
of [e]. *)


val ( -- ) : int -> int -> int BatEnum.t
(** Enumerate numbers.

[5 -- 10] is the enumeration 5,6,7,8,9,10.
[10 -- 5] is the empty enumeration*)

val ( --^ ) : int -> int -> int BatEnum.t
(** Enumerate numbers, without the right endpoint

[5 -- 10] is the enumeration 5,6,7,8,9.
*)

val ( --. ) : (float * float) -> float -> float BatEnum.t
(** [(a, step) --. b)] creates a float enumeration from [a] to [b] with an
increment of [step] between elements.

[(5.0, 1.0) --. 10.0] is the enumeration 5.0,6.0,7.0,8.0,9.0,10.0.
[(10.0, -1.0) --. 5.0] is the enumeration 10.0,9.0,8.0,7.0,6.0,5.0.
[(10.0, 1.0) --. 1.0] is the empty enumeration. *)

val ( --- ) : int -> int -> int BatEnum.t
(** As [--], but accepts enumerations in reverse order.

[5 --- 10] is the enumeration 5,6,7,8,9,10.
[10 --- 5] is the enumeration 10,9,8,7,6,5.*)

val ( --~ ) : char -> char -> char BatEnum.t
(** As ( -- ), but for characters.*)

val print : ?first:string -> ?last:string -> ?sep:string -> ('a BatInnerIO.output -> 'b -> unit) -> 'a BatInnerIO.output -> 'b BatEnum.t -> unit
(** Print and consume the contents of an enumeration.*)

(**/**)

(**
{6 Printing directives}
*)

(** Flags used to modify the printing behaviour *)
type printer_flags = {
  pf_width : int option;
  (** If with of printed material is less than this one, padding is
added *)
  pf_frac_digits : int option;
  (** When printing a float, print this many digits after the decimal point *)
  pf_padding_char : char;
  (** Character used for padding *)
  pf_justify : [ `right | `left ];
  (** Where to add the padding. Defaults to [`right] *)
  pf_positive_prefix : char option;
  (** Prefix positive numbers with this character *)
}

val default_printer_flags : printer_flags
  (** Default printer flags *)

(** {7 Equivalent of classical directives} *)

val printer_a : ((unit BatIO.output -> 'a -> unit) -> 'a -> 'b, 'b) BatPrint.directive
val printer_t : ((unit BatIO.output -> unit) -> 'a, 'a) BatPrint.directive
val printer_B : (bool -> 'a, 'a) BatPrint.directive
val printer_c : (char -> 'a, 'a) BatPrint.directive
val printer_C : (char -> 'a, 'a) BatPrint.directive
val printer_s : ?flags : printer_flags -> (string -> 'a, 'a) BatPrint.directive
val printer_S : ?flags : printer_flags -> (string -> 'a, 'a) BatPrint.directive

val printer_d : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_i : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_int : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_u : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_uint : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_x : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_X : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_hex : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_HEX : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_o : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_oct : ?flags : printer_flags -> (int -> 'a, 'a) BatPrint.directive
val printer_ld : ?flags : printer_flags -> (int32 -> 'a, 'a) BatPrint.directive
val printer_li : ?flags : printer_flags -> (int32 -> 'a, 'a) BatPrint.directive
val printer_lu : ?flags : printer_flags -> (int32 -> 'a, 'a) BatPrint.directive
val printer_lx : ?flags : printer_flags -> (int32 -> 'a, 'a) BatPrint.directive
val printer_lX : ?flags : printer_flags -> (int32 -> 'a, 'a) BatPrint.directive
val printer_lo : ?flags : printer_flags -> (int32 -> 'a, 'a) BatPrint.directive
val printer_Ld : ?flags : printer_flags -> (int64 -> 'a, 'a) BatPrint.directive
val printer_Li : ?flags : printer_flags -> (int64 -> 'a, 'a) BatPrint.directive
val printer_Lu : ?flags : printer_flags -> (int64 -> 'a, 'a) BatPrint.directive
val printer_Lx : ?flags : printer_flags -> (int64 -> 'a, 'a) BatPrint.directive
val printer_LX : ?flags : printer_flags -> (int64 -> 'a, 'a) BatPrint.directive
val printer_Lo : ?flags : printer_flags -> (int64 -> 'a, 'a) BatPrint.directive
val printer_nd : ?flags : printer_flags -> (nativeint -> 'a, 'a) BatPrint.directive
val printer_ni : ?flags : printer_flags -> (nativeint -> 'a, 'a) BatPrint.directive
val printer_nu : ?flags : printer_flags -> (nativeint -> 'a, 'a) BatPrint.directive
val printer_nx : ?flags : printer_flags -> (nativeint -> 'a, 'a) BatPrint.directive
val printer_nX : ?flags : printer_flags -> (nativeint -> 'a, 'a) BatPrint.directive
val printer_no : ?flags : printer_flags -> (nativeint -> 'a, 'a) BatPrint.directive

val printer_f : ?flags : printer_flags -> (float -> 'a, 'a) BatPrint.directive
val printer_F : ?flags : printer_flags -> (float -> 'a, 'a) BatPrint.directive

(** {7 Batteries-specific directives} *)

val printer_format : (('a, 'b) BatPrint.format -> 'a, 'b) BatPrint.directive
  (** [printer_format] takes a format, then the arguments of the format and
print according to it. For instance,

{[sprintf p"x = %format * %d" p"%d + %d" 1 3 5]} produces ["x = 1 + 3 * 5"]
*)

val printer_sc : ?flags : printer_flags -> ([> `Read] BatString.Cap.t -> 'a, 'a) BatPrint.directive
val printer_Sc : ?flags : printer_flags -> ([> `Read] BatString.Cap.t -> 'a, 'a) BatPrint.directive
(* val printer_text : (Ulib.Text.t -> 'a, 'a) BatPrint.directive *)
val printer_obj : (< print : unit BatIO.output -> unit; .. > -> 'a, 'a) BatPrint.directive
val printer_exn : (exn -> 'a, 'a) BatPrint.directive

(** {7 Value printers} *)

val bool_printer : bool BatValuePrinter.t
val int_printer : int BatValuePrinter.t
val char_printer : char BatValuePrinter.t
val int32_printer : int32 BatValuePrinter.t
val int64_printer : int64 BatValuePrinter.t
val nativeint_printer : nativeint BatValuePrinter.t
val float_printer : float BatValuePrinter.t
val string_printer : string BatValuePrinter.t
val list_printer : 'a BatValuePrinter.t -> 'a list BatValuePrinter.t
val array_printer : 'a BatValuePrinter.t -> 'a array BatValuePrinter.t
val option_printer : 'a BatValuePrinter.t -> 'a option BatValuePrinter.t
val maybe_printer : 'a BatValuePrinter.t -> 'a option BatValuePrinter.t
val exn_printer : exn BatValuePrinter.t

(**/**)

(**
{6 Results}
*)

(** This type represents the outcome of a function which has the
possibility of failure. Normal results of type ['a] are marked
with [Ok], while failure values of type ['b] are marked with
[Bad].

This is intended to be a safer alternative to functions raising
exceptions to signal failure. It is safer in that the possibility
of failure has to be handled before the result of that computation
can be used.

For more functions related to this type, see the {!BatResult} module.
*)
type ('a, 'b) result =
  | Ok of 'a
  | Bad of 'b
(** The result of a computation - either an [Ok] with the normal
result or a [Bad] with some value (often an exception) containing
failure information*)

val ignore_ok : ('a, exn) result -> unit
(** [ignore_ok (f x)] ignores the result of [f x] if it's ok, but
throws the exception contained if [Bad] is returned. *)

val ok : ('a, exn) result -> 'a
(** [f x |> ok] unwraps the [Ok] result of [f x] and returns it, or
throws the exception contained if [Bad] is returned. *)

val wrap : ('a -> 'b) -> 'a -> ('b, exn) result
(** [wrap f x] wraps a function that would normally throw an exception
on failure such that it now returns a result with either the [Ok]
return value or the [Bad] exception. *)


(**
{6 Thread-safety internals}

Unless you are attempting to adapt Batteries Included to a new model of
concurrency, you probably won't need this.
*)

val lock: BatConcurrent.lock ref
(**
A lock used to synchronize internal operations.

By default, this is {!BatConcurrent.nolock}. However, if you're
using a version of Batteries compiled in threaded mode, this uses
{!BatMutex}. If you're attempting to use Batteries with another
concurrency model, set the lock appropriately.
*)
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