module Pervasives: sig endThis 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 Pervasives.
Exceptions
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val raise : exn -> 'aval invalid_arg : string -> 'aInvalid_argument with the given string.val failwith : string -> 'aFailure with the given string.exception Exit
Exit exception is not raised by any library function. It is
provided for use in your programs.
Comparisons
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val (=) : 'a -> 'a -> boole1 = e2 tests for structural equality of e1 and e2.
Mutable structures (e.g. references and arrays) are equal
if and only if their current contents are structurally equal,
even if the two mutable objects are not the same physical object.
Equality between functional values may raise Invalid_argument.
Equality between cyclic data structures may not terminate.val (<>) : 'a -> 'a -> boolPervasives.(=).val (<) : 'a -> 'a -> boolPervasives.(>=).val (>) : 'a -> 'a -> boolPervasives.(>=).val (<=) : 'a -> 'a -> boolPervasives.(>=).val (>=) : 'a -> 'a -> bool(=). As in the case
of (=), mutable structures are compared by contents.
Comparison between functional values may raise Invalid_argument.
Comparison between cyclic structures may not terminate.val compare : 'a -> 'a -> intcompare x y returns 0 if x=y, a negative integer if
x<y, and a positive integer if x>y. The same restrictions
as for = apply. compare can be used as the comparison function
required by the Set.Make and Map.Make functors.val min : 'a -> 'a -> 'aval max : 'a -> 'a -> 'aval (==) : 'a -> 'a -> boole1 == e2 tests for physical equality of e1 and e2.
On integers and characters, physical equality is identical to structural
equality. On mutable structures, e1 == e2 is true if and only if
physical modification of e1 also affects e2.
On non-mutable structures, the behavior of (==) is
implementation-dependent; however, it is guaranteed that
e1 == e2 implies e1 = e2.val (!=) : 'a -> 'a -> boolPervasives.(==).
Boolean operations
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val not : bool -> boolval (&&) : bool -> bool -> boole1 && e2, e1 is evaluated first, and if it returns false,
e2 is not evaluated at all.val (&) : bool -> bool -> bool
val (||) : bool -> bool -> boole1 || e2, e1 is evaluated first, and if it returns true,
e2 is not evaluated at all.val or : bool -> bool -> bool
Integer arithmetic
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val (~-) : int -> int-e instead of ~-e.val succ : int -> intsucc x is x+1.val pred : int -> intpred x is x-1.val (+) : int -> int -> intval (-) : int -> int -> intval (*) : int -> int -> intval (/) : int -> int -> intDivision_by_zero if the second argument is 0.
Integer division rounds the real quotient of its arguments towards zero.
More precisely, if x >= 0 and y > 0, x / y is the greatest integer
less than or equal to the real quotient of x by y. Moreover,
(-x) / y = x / (-y) = -(x / y).val mod : int -> int -> inty is not zero, the result
of x mod y satisfies the following properties:
x = (x / y) * y + x mod y and
abs(x mod y) < abs(y).
If y = 0, x mod y raises Division_by_zero.
Notice that x mod y is negative if and only if x < 0.val abs : int -> intval max_int : intval min_int : int
Bitwise operations
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val land : int -> int -> intval lor : int -> int -> intval lxor : int -> int -> intval lnot : int -> intval lsl : int -> int -> intn lsl m shifts n to the left by m bits.
The result is unspecified if m < 0 or m >= bitsize,
where bitsize is 32 on a 32-bit platform and
64 on a 64-bit platform.val lsr : int -> int -> intn lsr m shifts n to the right by m bits.
This is a logical shift: zeroes are inserted regardless of
the sign of n.
The result is unspecified if m < 0 or m >= bitsize.val asr : int -> int -> intn asr m shifts n to the right by m bits.
This is an arithmetic shift: the sign bit of n is replicated.
The result is unspecified if m < 0 or m >= bitsize.
Floating-point arithmetic
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Caml's floating-point numbers follow the
IEEE 754 standard, using double precision (64 bits) numbers.
Floating-point operations never raise an exception on overflow,
underflow, division by zero, etc. Instead, special IEEE numbers
are returned as appropriate, such as infinity for 1.0 /. 0.0,
neg_infinity for -1.0 /. 0.0, and nan (``not a number'')
for 0.0 /. 0.0. These special numbers then propagate through
floating-point computations as expected: for instance,
1.0 /. infinity is 0.0, and any operation with nan as
argument returns nan as result.
val (~-.) : float -> float-.e instead of ~-.e.val (+.) : float -> float -> floatval (-.) : float -> float -> floatval (*.) : float -> float -> floatval (/.) : float -> float -> floatval (**) : float -> float -> floatval sqrt : float -> floatval exp : float -> floatval log : float -> floatval log10 : float -> floatval cos : float -> floatPervasives.atan2.val sin : float -> floatPervasives.atan2.val tan : float -> floatPervasives.atan2.val acos : float -> floatPervasives.atan2.val asin : float -> floatPervasives.atan2.val atan : float -> floatPervasives.atan2.val atan2 : float -> float -> floatval cosh : float -> floatPervasives.tanh.val sinh : float -> floatPervasives.tanh.val tanh : float -> floatval ceil : float -> floatPervasives.floor.val floor : float -> floatfloor f returns the greatest integer value less than or
equal to f.
ceil f returns the least integer value greater than or
equal to f.val abs_float : float -> floatval mod_float : float -> float -> floatmod_float a b returns the remainder of a with respect to
b. The returned value is a -. n *. b, where n
is the quotient a /. b rounded towards zero to an integer.val frexp : float -> float * intfrexp f returns the pair of the significant
and the exponent of f. When f is zero, the
significant x and the exponent n of f are equal to
zero. When f is non-zero, they are defined by
f = x *. 2 ** n and 0.5 <= x < 1.0.val ldexp : float -> int -> floatldexp x n returns x *. 2 ** n.val modf : float -> float * floatmodf f returns the pair of the fractional and integral
part of f.val float : int -> floatPervasives.float_of_int.val float_of_int : int -> floatval truncate : float -> intPervasives.int_of_float.val int_of_float : float -> intval infinity : floatval neg_infinity : floatval nan : float0.0 /. 0.0. Stands for
``not a number''.val max_float : floatfloat.val min_float : floatfloat.val epsilon_float : floatx such that 1.0 +. x <> 1.0.type fpclass =
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FP_normal |
(* | Normal number, none of the below | *) |
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FP_subnormal |
(* | Number very close to 0.0, has reduced precision | *) |
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FP_zero |
(* | Number is 0.0 or -0.0 | *) |
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FP_infinite |
(* | Number is positive or negative infinity | *) |
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FP_nan |
(* | Not a number: result of an undefined operation | *) |
Pervasives.classify_float function.val classify_float : float -> fpclass
String operations
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More string operations are provided in module String.
val (^) : string -> string -> string
Character operations
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More character operations are provided in module Char.
val int_of_char : char -> intval char_of_int : int -> charInvalid_argument "char_of_int" if the argument is
outside the range 0--255.
Unit operations
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val ignore : 'a -> unit().
For instance, ignore(f x) discards the result of
the side-effecting function f. It is equivalent to
f x; (), except that the latter may generate a
compiler warning; writing ignore(f x) instead
avoids the warning.
String conversion functions
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val string_of_bool : bool -> stringval bool_of_string : string -> boolInvalid_argument "bool_of_string" if the string is not
"true" or "false".val string_of_int : int -> stringval int_of_string : string -> int0x, 0o or 0b
respectively.
Raise Failure "int_of_string" if the given string is not
a valid representation of an integer.val string_of_float : float -> stringval float_of_string : string -> floatFailure "float_of_string"
if the given string is not a valid representation of a float.
Pair operations
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val fst : 'a * 'b -> 'aval snd : 'a * 'b -> 'b
List operations
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More list operations are provided in module List.
val (@) : 'a list -> 'a list -> 'a list
Input/output
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type in_channel
type out_channel
val stdin : in_channelval stdout : out_channelval stderr : out_channel
Output functions on standard output
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val print_char : char -> unitval print_string : string -> unitval print_int : int -> unitval print_float : float -> unitval print_endline : string -> unitval print_newline : unit -> unit
Output functions on standard error
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val prerr_char : char -> unitval prerr_string : string -> unitval prerr_int : int -> unitval prerr_float : float -> unitval prerr_endline : string -> unitval prerr_newline : unit -> unit
Input functions on standard input
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val read_line : unit -> stringval read_int : unit -> intFailure "int_of_string"
if the line read is not a valid representation of an integer.val read_float : unit -> float
General output functions
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type open_flag =
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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: always write at end of file. | *) |
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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. | *) |
val open_out : string -> out_channelSys_error if the file could not be opened.val open_out_bin : string -> out_channelPervasives.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 Pervasives.open_out.val open_out_gen : open_flag list -> int -> string -> out_channelmode
specify the opening mode. The extra argument perm specifies
the file permissions, in case the file must be created.
Pervasives.open_out and Pervasives.open_out_bin are special
cases of this function.val flush : out_channel -> unitval flush_all : unit -> unitval output_char : out_channel -> char -> unitval output_string : out_channel -> string -> unitval output : out_channel -> string -> int -> int -> unitoutput oc buf pos len writes len characters from string buf,
starting at offset pos, to the given output channel oc.
Raise Invalid_argument "output" if pos and len do not
designate a valid substring of buf.val output_byte : out_channel -> int -> unitval output_binary_int : out_channel -> int -> unitPervasives.input_binary_int function. The format is compatible across
all machines for a given version of Objective Caml.val output_value : out_channel -> 'a -> unitPervasives.input_value. See the description of module
Marshal for more information. Pervasives.output_value is equivalent
to Marshal.to_channel with an empty list of flags.val seek_out : out_channel -> int -> unitseek_out chan pos sets the current writing position to pos
for channel chan. This works only for regular files. On
files of other kinds (such as terminals, pipes and sockets),
the behavior is unspecified.val pos_out : out_channel -> intval out_channel_length : out_channel -> intval close_out : out_channel -> unitSys_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.val set_binary_mode_out : out_channel -> bool -> unitset_binary_mode_out oc true sets the channel oc to binary
mode: no translations take place during output.
set_binary_mode_out oc false sets the channel oc to text
mode: depending on the operating system, some translations
may take place during output. For instance, under Windows,
end-of-lines will be translated from \n to \r\n.
This function has no effect under operating systems that
do not distinguish between text mode and binary mode.
General input functions
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val open_in : string -> in_channelSys_error if the file could not be opened.val open_in_bin : string -> in_channelPervasives.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 -> in_channelmode and perm specify the opening mode and file permissions.
Pervasives.open_in and Pervasives.open_in_bin are special
cases of this function.val input_char : in_channel -> charEnd_of_file if there are no more characters to read.val input_line : in_channel -> stringEnd_of_file if the end of the file is reached
at the beginning of line.val input : in_channel -> string -> int -> int -> intinput 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.)
Exception Invalid_argument "input" is raised if pos and len
do not designate a valid substring of buf.val really_input : in_channel -> string -> int -> int -> unitreally_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 "really_input" if
pos and len do not designate a valid substring of buf.val input_byte : in_channel -> intPervasives.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 : in_channel -> intPervasives.output_binary_int.
Raise End_of_file if an end of file was reached while reading the
integer.val input_value : in_channel -> 'aPervasives.output_value, and return the corresponding value.
This function is identical to Marshal.from_channel;
see the description of module Marshal for more information,
in particular concerning the lack of type safety.val seek_in : in_channel -> int -> unitseek_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.val pos_in : in_channel -> intval in_channel_length : in_channel -> intval close_in : in_channel -> unitSys_error
exception when they are applied to a closed input channel,
except close_in, which does nothing when applied to an already
closed channel.val set_binary_mode_in : in_channel -> bool -> unitset_binary_mode_in ic true sets the channel ic to binary
mode: no translations take place during input.
set_binary_mode_out ic false sets the channel ic to text
mode: depending on the operating system, some translations
may take place during input. For instance, under Windows,
end-of-lines will be translated from \r\n to \n.
This function has no effect under operating systems that
do not distinguish between text mode and binary mode.
Operations on large files
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module LargeFile: sig end
References
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type 'a ref = {
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mutable contents : |
'a.val ref : 'a -> 'a refval (!) : 'a ref -> 'a!r returns the current contents of reference r.
Equivalent to fun r -> r.contents.val (:=) : 'a ref -> 'a -> unitr := a stores the value of a in reference r.
Equivalent to fun r v -> r.contents <- v.val incr : int ref -> unitfun r -> r := succ !r.val decr : int ref -> unitfun r -> r := pred !r.
Program termination
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val exit : int -> 'aexit 0 is performed each time a program
terminates normally. An implicit exit 2 is performed if the program
terminates early because of an uncaught exception.val at_exit : (unit -> unit) -> unitat_exit
will be called when the program executes Pervasives.exit,
or terminates, either normally or because of an uncaught exception.
The functions are called in ``last in, first out'' order:
the function most recently added with at_exit is called first.