542 lines
26 KiB
OCaml
542 lines
26 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Module [Pervasives]: the initially opened module *)
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(* This module provides the built-in types (numbers, booleans,
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strings, exceptions, references, lists, arrays, input-output channels, ...)
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and the basic operations over these types.
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This module is automatically opened at the beginning of each compilation.
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All components of this module can therefore be referred by their short
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name, without prefixing them by [Pervasives]. *)
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(*** Predefined types *)
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(*- type int *)
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(* The type of integer numbers. *)
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(*- type char *)
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(* The type of characters. *)
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(*- type string *)
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(* The type of character strings. *)
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(*- type float *)
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(* The type of floating-point numbers. *)
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(*- type bool *)
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(* The type of booleans (truth values). *)
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(*- type unit = () *)
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(* The type of the unit value. *)
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(*- type exn *)
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(* The type of exception values. *)
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(*- type 'a array *)
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(* The type of arrays whose elements have type ['a]. *)
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(*- type 'a list = [] | :: of 'a * 'a list *)
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(* The type of lists whose elements have type ['a]. *)
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type 'a option = None | Some of 'a
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(* The type of optional values. *)
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(*- type ('a, 'b, 'c) format *)
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(* The type of format strings. ['a] is the type of the parameters
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of the format, ['c] is the result type for the [printf]-style
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function, and ['b] is the type of the first argument given to
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[%a] and [%t] printing functions (see module [Printf]). *)
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(*** Exceptions *)
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external raise : exn -> 'a = "%raise"
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(* Raise the given exception value *)
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(*- exception Match_failure of string * int * int *)
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(* Exception raised when none of the cases of a pattern-matching
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apply. The arguments are the location of the pattern-matching
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in the source code (file name, position of first character,
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position of last character). *)
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(*- exception Invalid_argument of string *)
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(* Exception raised by library functions to signal that the given
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arguments do not make sense. *)
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(*- exception Failure of string *)
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(* Exception raised by library functions to signal that they are
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undefined on the given arguments. *)
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(*- exception Not_found *)
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(* Exception raised by search functions when the desired object
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could not be found. *)
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(*- exception Out_of_memory *)
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(* Exception raised by the garbage collector
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when there is insufficient memory to complete the computation. *)
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(*- exception Sys_error of string *)
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(* Exception raised by the input/output functions to report
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an operating system error. *)
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(*- exception End_of_file *)
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(* Exception raised by input functions to signal that the
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end of file has been reached. *)
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(*- exception Division_by_zero *)
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(* Exception raised by division and remainder operations
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when their second argument is null. *)
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exception Exit
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(* This exception is not raised by any library function. It is
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provided for use in your programs. *)
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val invalid_arg: string -> 'a
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(* Raise exception [Invalid_argument] with the given string. *)
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val failwith: string -> 'a
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(* Raise exception [Failure] with the given string. *)
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(*** Comparisons *)
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external (=) : 'a -> 'a -> bool = "%equal"
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(* [e1 = e2] tests for structural equality of [e1] and [e2].
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Mutable structures (e.g. references and arrays) are equal
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if and only if their current contents are structurally equal,
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even if the two mutable objects are not the same physical object.
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Equality between functional values raises [Invalid_argument].
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Equality between cyclic data structures may not terminate. *)
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external (<>) : 'a -> 'a -> bool = "%notequal"
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(* Negation of [(=)]. *)
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external (<) : 'a -> 'a -> bool = "%lessthan"
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external (>) : 'a -> 'a -> bool = "%greaterthan"
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external (<=) : 'a -> 'a -> bool = "%lessequal"
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external (>=) : 'a -> 'a -> bool = "%greaterequal"
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(* Structural ordering functions. These functions coincide with
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the usual orderings over integer, string and floating-point
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numbers, and extend them to a total ordering over all types.
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The ordering is compatible with [(=)]. As in the case
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of [(=)], mutable structures are compared by contents.
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Comparison between functional values raises [Invalid_argument].
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Comparison between cyclic structures may not terminate. *)
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external compare: 'a -> 'a -> int = "compare" "noalloc"
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(* [compare x y] returns [0] if [x=y], a negative integer if
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[x<y], and a positive integer if [x>y]. The same restrictions
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as for [=] apply. [compare] can be used as the comparison function
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required by the [Set] and [Map] modules. *)
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val min: 'a -> 'a -> 'a
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(* Return the smaller of the two arguments. *)
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val max: 'a -> 'a -> 'a
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(* Return the greater of the two arguments. *)
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external (==) : 'a -> 'a -> bool = "%eq"
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(* [e1 == e2] tests for physical equality of [e1] and [e2].
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On integers and characters, it is the same as structural
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equality. On mutable structures, [e1 == e2] is true if and only if
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physical modification of [e1] also affects [e2].
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On non-mutable structures, the behavior of [(==)] is
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implementation-dependent, except that [e1 == e2] implies
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[e1 = e2]. *)
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external (!=) : 'a -> 'a -> bool = "%noteq"
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(* Negation of [(==)]. *)
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(*** Boolean operations *)
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external not : bool -> bool = "%boolnot"
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(* The boolean negation. *)
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external (&) : bool -> bool -> bool = "%sequand"
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external (&&) : bool -> bool -> bool = "%sequand"
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(* The boolean ``and''. Evaluation is sequential, left-to-right:
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in [e1 & e2], [e1] is evaluated first, and if it returns [false],
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[e2] is not evaluated at all. *)
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external (or) : bool -> bool -> bool = "%sequor"
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external (||) : bool -> bool -> bool = "%sequor"
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(* The boolean ``or''. Evaluation is sequential, left-to-right:
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in [e1 or e2], [e1] is evaluated first, and if it returns [true],
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[e2] is not evaluated at all. *)
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(*** Integer arithmetic *)
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(* Integers are 31 bits wide (or 63 bits on 64-bit processors).
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All operations are taken modulo $2^{31}$ (or $2^{63}$).
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They do not fail on overflow. *)
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external (~-) : int -> int = "%negint"
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(* Unary negation. You can also write [-e] instead of [~-e]. *)
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external succ : int -> int = "%succint"
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(* [succ x] is [x+1]. *)
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external pred : int -> int = "%predint"
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(* [pred x] is [x-1]. *)
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external (+) : int -> int -> int = "%addint"
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(* Integer addition. *)
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external (-) : int -> int -> int = "%subint"
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(* Integer subtraction. *)
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external ( * ) : int -> int -> int = "%mulint"
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(* Integer multiplication. *)
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external (/) : int -> int -> int = "%divint"
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external (mod) : int -> int -> int = "%modint"
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(* Integer division and remainder.
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Raise [Division_by_zero] if the second argument is 0.
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If one of the arguments is negative, the result is
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platform-dependent. *)
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val abs : int -> int
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(* Return the absolute value of the argument. *)
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val max_int: int
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val min_int: int
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(* The greatest and smallest representable integers. *)
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(** Bitwise operations *)
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external (land) : int -> int -> int = "%andint"
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(* Bitwise logical and. *)
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external (lor) : int -> int -> int = "%orint"
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(* Bitwise logical or. *)
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external (lxor) : int -> int -> int = "%xorint"
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(* Bitwise logical exclusive or. *)
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val lnot: int -> int
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(* Bitwise logical negation. *)
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external (lsl) : int -> int -> int = "%lslint"
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(* [n lsl m] shifts [n] to the left by [m] bits. *)
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external (lsr) : int -> int -> int = "%lsrint"
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(* [n lsr m] shifts [n] to the right by [m] bits.
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This is a logical shift: zeroes are inserted regardless of
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the sign of [n].*)
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external (asr) : int -> int -> int = "%asrint"
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(* [n asr m] shifts [n] to the right by [m] bits.
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This is an arithmetic shift: the sign bit of [n] is replicated. *)
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(*** Floating-point arithmetic *)
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(* On most platforms, Caml's floating-point numbers follow the
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IEEE 754 standard, using double precision (64 bits) numbers.
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Floating-point operations do not fail on overflow or underflow,
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but return denormal numbers. *)
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external (~-.) : float -> float = "%negfloat"
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(* Unary negation. You can also write [-.e] instead of [~-.e]. *)
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external (+.) : float -> float -> float = "%addfloat"
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(* Floating-point addition *)
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external (-.) : float -> float -> float = "%subfloat"
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(* Floating-point subtraction *)
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external ( *. ) : float -> float -> float = "%mulfloat"
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(* Floating-point multiplication *)
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external (/.) : float -> float -> float = "%divfloat"
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(* Floating-point division. *)
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external ( ** ) : float -> float -> float = "power_float" "pow" "float"
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(* Exponentiation *)
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external exp : float -> float = "exp_float" "exp" "float"
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external log : float -> float = "log_float" "log" "float"
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external sqrt : float -> float = "sqrt_float" "sqrt" "float"
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external sin : float -> float = "sin_float" "sin" "float"
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external cos : float -> float = "cos_float" "cos" "float"
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external tan : float -> float = "tan_float" "tan" "float"
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external asin : float -> float = "asin_float" "asin" "float"
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external acos : float -> float = "acos_float" "acos" "float"
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external atan : float -> float = "atan_float" "atan" "float"
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external atan2 : float -> float -> float = "atan2_float" "atan2" "float"
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(* Usual transcendental functions on floating-point numbers. *)
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external abs_float : float -> float = "%absfloat"
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(* Return the absolute value of the argument. *)
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external float : int -> float = "%floatofint"
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(* Convert an integer to floating-point. *)
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external truncate : float -> int = "%intoffloat"
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(* Truncate the given floating-point number to an integer.
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The result is unspecified if it falls outside the
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range of representable integers. *)
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(*** String operations *)
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(* More string operations are provided in module [String]. *)
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val (^) : string -> string -> string
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(* String concatenation. *)
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(*** String conversion functions *)
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val string_of_bool : bool -> string
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(* Return the string representation of a boolean. *)
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val string_of_int : int -> string
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(* Return the string representation of an integer, in decimal. *)
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external int_of_string : string -> int = "int_of_string"
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(* Convert the given string to an integer.
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The string is read in decimal (by default) or in hexadecimal,
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octal or binary if the string begins with [0x], [0o] or [0b]
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respectively.
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Raise [Failure "int_of_string"] if the given string is not
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a valid representation of an integer. *)
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val string_of_float : float -> string
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(* Return the string representation of a floating-point number. *)
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external float_of_string : string -> float = "float_of_string"
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(* Convert the given string to a float.
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The result is unspecified if the given string is not
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a valid representation of a float. *)
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(*** Pair operations *)
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external fst : 'a * 'b -> 'a = "%field0"
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(* Return the first component of a pair. *)
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external snd : 'a * 'b -> 'b = "%field1"
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(* Return the second component of a pair. *)
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(*** List operations *)
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(* More list operations are provided in module [List]. *)
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val (@) : 'a list -> 'a list -> 'a list
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(* List concatenation. *)
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(*** Input/output *)
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type in_channel
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type out_channel
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(* The types of input channels and output channels. *)
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val stdin : in_channel
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val stdout : out_channel
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val stderr : out_channel
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(* The standard input, standard output, and standard error output
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for the process. *)
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(** Output functions on standard output *)
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val print_char : char -> unit
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(* Print a character on standard output. *)
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val print_string : string -> unit
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(* Print a string on standard output. *)
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val print_int : int -> unit
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(* Print an integer, in decimal, on standard output. *)
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val print_float : float -> unit
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(* Print a floating-point number, in decimal, on standard output. *)
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val print_endline : string -> unit
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(* Print a string, followed by a newline character, on
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standard output. *)
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val print_newline : unit -> unit
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(* Print a newline character on standard output, and flush
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standard output. This can be used to simulate line
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buffering of standard output. *)
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(** Output functions on standard error *)
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val prerr_char : char -> unit
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(* Print a character on standard error. *)
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val prerr_string : string -> unit
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(* Print a string on standard error. *)
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val prerr_int : int -> unit
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(* Print an integer, in decimal, on standard error. *)
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val prerr_float : float -> unit
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(* Print a floating-point number, in decimal, on standard error. *)
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val prerr_endline : string -> unit
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(* Print a string, followed by a newline character on standard error
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and flush standard error. *)
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val prerr_newline : unit -> unit
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(* Print a newline character on standard error, and flush
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standard error. *)
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(** Input functions on standard input *)
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val read_line : unit -> string
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(* Flush standard output, then read characters from standard input
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until a newline character is encountered. Return the string of
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all characters read, without the newline character at the end. *)
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val read_int : unit -> int
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(* Flush standard output, then read one line from standard input
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and convert it to an integer. Raise [Failure "int_of_string"]
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if the line read is not a valid representation of an integer. *)
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val read_float : unit -> float
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(* Flush standard output, then read one line from standard input
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and convert it to a floating-point number.
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The result is unspecified if the line read is not a valid
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representation of a floating-point number. *)
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(** General output functions *)
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type open_flag =
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Open_rdonly | Open_wronly | Open_append
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| Open_creat | Open_trunc | Open_excl
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| Open_binary | Open_text | Open_nonblock
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(* Opening modes for [open_out_gen] and [open_in_gen].
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- [Open_rdonly]: open for reading.
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- [Open_wronly]: open for writing.
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- [Open_append]: open for appending.
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- [Open_creat]: create the file if it does not exist.
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- [Open_trunc]: empty the file if it already exists.
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- [Open_excl]: fail if the file already exists.
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- [Open_binary]: open in binary mode (no conversion).
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- [Open_text]: open in text mode (may perform conversions).
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- [Open_nonblock]: open in non-blocking mode. *)
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val open_out : string -> out_channel
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(* Open the named file for writing, and return a new output channel
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on that file, positionned at the beginning of the file. The
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file is truncated to zero length if it already exists. It
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is created if it does not already exists.
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Raise [Sys_error] if the file could not be opened. *)
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val open_out_bin : string -> out_channel
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(* Same as [open_out], but the file is opened in binary mode,
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so that no translation takes place during writes. On operating
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systems that do not distinguish between text mode and binary
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mode, this function behaves like [open_out]. *)
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val open_out_gen : open_flag list -> int -> string -> out_channel
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(* [open_out_gen mode rights filename] opens the file named
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[filename] for writing, as above. The extra argument [mode]
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specify the opening mode. The extra argument [rights] specifies
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the file permissions, in case the file must be created.
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[open_out] and [open_out_bin] are special cases of this function. *)
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external flush : out_channel -> unit = "flush"
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(* Flush the buffer associated with the given output channel,
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performing all pending writes on that channel.
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Interactive programs must be careful about flushing standard
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output and standard error at the right time. *)
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external output_char : out_channel -> char -> unit = "output_char"
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(* Write the character on the given output channel. *)
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val output_string : out_channel -> string -> unit
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(* Write the string on the given output channel. *)
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val output : out_channel -> string -> int -> int -> unit
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(* [output chan buff ofs len] writes [len] characters from string
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[buff], starting at offset [ofs], to the output channel [chan].
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Raise [Invalid_argument "output"] if [ofs] and [len] do not
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designate a valid substring of [buff]. *)
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external output_byte : out_channel -> int -> unit = "output_char"
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(* Write one 8-bit integer (as the single character with that code)
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on the given output channel. The given integer is taken modulo
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256. *)
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external output_binary_int : out_channel -> int -> unit = "output_int"
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(* Write one integer in binary format on the given output channel.
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The only reliable way to read it back is through the
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[input_binary_int] function. The format is compatible across
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all machines for a given version of Caml Light. *)
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external output_value : out_channel -> 'a -> unit = "output_value"
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(* Write the representation of a structured value of any type
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to a channel. Circularities and sharing inside the value
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are detected and preserved. The object can be read back,
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by the function [input_value]. The format is compatible across
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all machines for a given version of Caml Light. *)
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external seek_out : out_channel -> int -> unit = "seek_out"
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(* [seek_out chan pos] sets the current writing position to [pos]
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for channel [chan]. This works only for regular files. On
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files of other kinds (such as terminals, pipes and sockets),
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the behavior is unspecified. *)
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external pos_out : out_channel -> int = "pos_out"
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(* Return the current writing position for the given channel. *)
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external out_channel_length : out_channel -> int = "channel_size"
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(* Return the total length (number of characters) of the
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given channel. This works only for regular files. On files of
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other kinds, the result is meaningless. *)
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val close_out : out_channel -> unit
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(* Close the given channel, flushing all buffered write operations.
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The behavior is unspecified if any of the functions above is
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called on a closed channel. *)
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(** General input functions *)
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val open_in : string -> in_channel
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(* Open the named file for reading, and return a new input channel
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on that file, positionned at the beginning of the file.
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Raise [Sys_error] if the file could not be opened. *)
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val open_in_bin : string -> in_channel
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(* Same as [open_in], but the file is opened in binary mode,
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so that no translation takes place during reads. On operating
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systems that do not distinguish between text mode and binary
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mode, this function behaves like [open_in]. *)
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val open_in_gen : open_flag list -> int -> string -> in_channel
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(* [open_in_gen mode rights filename] opens the file named
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[filename] for reading, as above. The extra arguments
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[mode] and [rights] specify the opening mode and file permissions.
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[open_in] and [open_in_bin] are special cases of this function. *)
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external input_char : in_channel -> char = "input_char"
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(* Read one character from the given input channel.
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Raise [End_of_file] if there are no more characters to read. *)
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val input_line : in_channel -> string
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(* Read characters from the given input channel, until a
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newline character is encountered. Return the string of
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all characters read, without the newline character at the end.
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Raise [End_of_file] if the end of the file is reached
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at the beginning of line. *)
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val input : in_channel -> string -> int -> int -> int
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(* [input chan buff ofs len] attempts to read [len] characters
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from channel [chan], storing them in string [buff], starting at
|
|
character number [ofs]. It returns the actual number of characters
|
|
read, between 0 and [len] (inclusive).
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|
A return value of 0 means that the end of file was reached.
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|
A return value between 0 and [len] exclusive means that
|
|
no more characters were available at that time; [input] must be
|
|
called again to read the remaining characters, if desired.
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|
Exception [Invalid_argument "input"] is raised if [ofs] and [len]
|
|
do not designate a valid substring of [buff]. *)
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|
val really_input : in_channel -> string -> int -> int -> unit
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|
(* [really_input chan buff ofs len] reads [len] characters
|
|
from channel [chan], storing them in string [buff], starting at
|
|
character number [ofs]. Raise [End_of_file] if
|
|
the end of file is reached before [len] characters have been read.
|
|
Raise [Invalid_argument "really_input"] if
|
|
[ofs] and [len] do not designate a valid substring of [buff]. *)
|
|
external input_byte : in_channel -> int = "input_char"
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|
(* Same as [input_char], but return the 8-bit integer representing
|
|
the character.
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|
Raise [End_of_file] if an end of file was reached. *)
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|
external input_binary_int : in_channel -> int = "input_int"
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|
(* Read an integer encoded in binary format from the given input
|
|
channel. See [output_binary_int].
|
|
Raise [End_of_file] if an end of file was reached while reading the
|
|
integer. *)
|
|
external input_value : in_channel -> 'a = "input_value"
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|
(* Read the representation of a structured value, as produced
|
|
by [output_value] or [output_compact_value], and return
|
|
the corresponding value.
|
|
This is not type-safe. The type of the returned object is
|
|
not ['a] properly speaking: the returned object has one
|
|
unique type, which cannot be determined at compile-time.
|
|
The programmer should explicitly give the expected type of the
|
|
returned value, using the following syntax:
|
|
[(input_value chan : type)].
|
|
The behavior is unspecified if the object in the file does not
|
|
belong to the given type. *)
|
|
external seek_in : in_channel -> int -> unit = "seek_in"
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|
(* [seek_in chan pos] sets the current reading position to [pos]
|
|
for channel [chan]. This works only for regular files. On
|
|
files of other kinds, the behavior is unspecified. *)
|
|
external pos_in : in_channel -> int = "pos_in"
|
|
(* Return the current reading position for the given channel. *)
|
|
external in_channel_length : in_channel -> int = "channel_size"
|
|
(* Return the total length (number of characters) of the
|
|
given channel. This works only for regular files. On files of
|
|
other kinds, the result is meaningless. *)
|
|
external close_in : in_channel -> unit = "close_channel"
|
|
(* Close the given channel. Anything can happen if any of the
|
|
functions above is called on a closed channel. *)
|
|
|
|
(*** References *)
|
|
|
|
type 'a ref = { mutable contents: 'a }
|
|
(* The type of references (mutable indirection cells) containing
|
|
a value of type ['a]. *)
|
|
external ref : 'a -> 'a ref = "%makemutable"
|
|
(* Return a fresh reference containing the given value. *)
|
|
external (!) : 'a ref -> 'a = "%field0"
|
|
(* [!r] returns the current contents of reference [r].
|
|
Could be defined as [fun r -> r.contents]. *)
|
|
external (:=) : 'a ref -> 'a -> unit = "%setfield0"
|
|
(* [r := a] stores the value of [a] in reference [r].
|
|
Could be defined as [fun r v -> r.contents <- v]. *)
|
|
external incr : int ref -> unit = "%incr"
|
|
(* Increment the integer contained in the given reference.
|
|
Could be defined as [fun r -> r := succ !r]. *)
|
|
external decr : int ref -> unit = "%decr"
|
|
(* Decrement the integer contained in the given reference.
|
|
Could be defined as [fun r -> r := pred !r]. *)
|
|
|
|
(*** Program termination *)
|
|
|
|
val exit : int -> 'a
|
|
(* Flush all pending writes on [stdout] and [stderr],
|
|
and terminate the process, returning the given status code
|
|
to the operating system (usually 0 to indicate no errors,
|
|
and a small positive integer to indicate failure.)
|
|
An implicit [exit 0] is performed each time a program
|
|
terminates normally (but not if it terminates because of
|
|
an uncaught exception). *)
|
|
|
|
val at_exit: (unit -> unit) -> unit
|
|
(* Register the given function to be called at program
|
|
termination time. The functions registered with [at_exit]
|
|
will be called in some unspecified order when the program
|
|
executes [exit]. They will not be called if the program
|
|
terminates because of an uncaught exception. *)
|
|
|
|
(*--*)
|
|
|
|
(*** For system use only, not for the casual user *)
|
|
|
|
val unsafe_really_input : in_channel -> string -> int -> int -> unit
|