Make.Pervasives
The OCaml Standard library.
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 Stdlib
.
It particular, it provides the basic operations over the built-in types (numbers, booleans, byte sequences, strings, exceptions, references, lists, arrays, input-output channels, ...) and the standard library modules.
The Exit
exception is not raised by any library function. It is provided for use in your programs.
The boolean 'and'. Evaluation is sequential, left-to-right: in e1 && e2
, e1
is evaluated first, and if it returns false
, e2
is not evaluated at all. Right-associative operator, see Ocaml_operators
for more information.
The boolean 'or'. Evaluation is sequential, left-to-right: in e1 || e2
, e1
is evaluated first, and if it returns true
, e2
is not evaluated at all. Right-associative operator, see Ocaml_operators
for more information.
__LOC__
returns the location at which this expression appears in the file currently being parsed by the compiler, with the standard error format of OCaml: "File %S, line %d, characters %d-%d".
__LINE__
returns the line number at which this expression appears in the file currently being parsed by the compiler.
__POS__
returns a tuple (file,lnum,cnum,enum)
, corresponding to the location at which this expression appears in the file currently being parsed by the compiler. file
is the current filename, lnum
the line number, cnum
the character position in the line and enum
the last character position in the line.
__LOC_OF__ expr
returns a pair (loc, expr)
where loc
is the location of expr
in the file currently being parsed by the compiler, with the standard error format of OCaml: "File %S, line %d, characters %d-%d".
__LINE_OF__ expr
returns a pair (line, expr)
, where line
is the line number at which the expression expr
appears in the file currently being parsed by the compiler.
__POS_OF__ expr
returns a pair (loc,expr)
, where loc
is a tuple (file,lnum,cnum,enum)
corresponding to the location at which the expression expr
appears in the file currently being parsed by the compiler. file
is the current filename, lnum
the line number, cnum
the character position in the line and enum
the last character position in the line.
Reverse-application operator: x |> f |> g
is exactly equivalent to g (f (x))
. Left-associative operator, see Ocaml_operators
for more information.
Application operator: g @@ f @@ x
is exactly equivalent to g (f (x))
. Right-associative operator, see Ocaml_operators
for more information.
Integers are Sys.int_size
bits wide. All operations are taken modulo 2Sys.int_size
. They do not fail on overflow.
Unary negation. You can also write - e
instead of ~- e
. Unary operator, see Ocaml_operators
for more information.
Unary addition. You can also write + e
instead of ~+ e
. Unary operator, see Ocaml_operators
for more information.
Integer addition. Left-associative operator, see Ocaml_operators
for more information.
Integer subtraction. Left-associative operator, , see Ocaml_operators
for more information.
Integer multiplication. Left-associative operator, see Ocaml_operators
for more information.
Integer division. Raise Division_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)
. Left-associative operator, see Ocaml_operators
for more information.
Integer remainder. If y
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) - 1
. If y = 0
, x mod y
raises Division_by_zero
. Note that x mod y
is negative only if x < 0
. Raise Division_by_zero
if y
is zero. Left-associative operator, see Ocaml_operators
for more information.
Return the absolute value of the argument. Note that this may be negative if the argument is min_int
.
Bitwise logical and. Left-associative operator, see Ocaml_operators
for more information.
Bitwise logical or. Left-associative operator, see Ocaml_operators
for more information.
Bitwise logical exclusive or. Left-associative operator, see Ocaml_operators
for more information.
n lsl m
shifts n
to the left by m
bits. The result is unspecified if m < 0
or m > Sys.int_size
. Right-associative operator, see Ocaml_operators
for more information.
n 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 > Sys.int_size
. Right-associative operator, see Ocaml_operators
for more information.
n 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 > Sys.int_size
. Right-associative operator, see Ocaml_operators
for more information.
More string operations are provided in module String
.
String concatenation. Right-associative operator, see Ocaml_operators
for more information.
More character operations are provided in module Char
.
Return the character with the given ASCII code. Raise Invalid_argument "char_of_int"
if the argument is outside the range 0--255.
Discard the value of its argument and return ()
. 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.
Return the string representation of a boolean. As the returned values may be shared, the user should not modify them directly.
Convert the given string to a boolean.
Return None
if the string is not "true"
or "false"
.
Convert the given string to an integer. The string is read in decimal (by default, or if the string begins with 0u
), in hexadecimal (if it begins with 0x
or 0X
), in octal (if it begins with 0o
or 0O
), or in binary (if it begins with 0b
or 0B
).
The 0u
prefix reads the input as an unsigned integer in the range [0, 2*max_int+1]
. If the input exceeds max_int
it is converted to the signed integer min_int + input - max_int - 1
.
The _
(underscore) character can appear anywhere in the string and is ignored.
Return None
if the given string is not a valid representation of an integer, or if the integer represented exceeds the range of integers representable in type int
.
More list operations are provided in module List
.
List concatenation. Not tail-recursive (length of the first argument). Right-associative operator, see Ocaml_operators
for more information.
The type of references (mutable indirection cells) containing a value of type 'a
.
val ref : 'a -> 'a ref
Return a fresh reference containing the given value.
val (!) : 'a ref -> 'a
!r
returns the current contents of reference r
. Equivalent to fun r -> r.contents
. Unary operator, see Ocaml_operators
for more information.
val (:=) : 'a ref -> 'a -> unit
r := a
stores the value of a
in reference r
. Equivalent to fun r v -> r.contents <- v
. Right-associative operator, see Ocaml_operators
for more information.
val incr : int ref -> unit
Increment the integer contained in the given reference. Equivalent to fun r -> r := succ !r
.
val decr : int ref -> unit
Decrement the integer contained in the given reference. Equivalent to fun r -> r := pred !r
.
Format strings are character strings with special lexical conventions that defines the functionality of formatted input/output functions. Format strings are used to read data with formatted input functions from module Scanf
and to print data with formatted output functions from modules Printf
and Format
.
Format strings are made of three kinds of entities:
'%'
followed by one or more characters specifying what kind of argument to read or print,'@'
followed by one or more characters specifying how to read or print the argument,There is an additional lexical rule to escape the special characters '%'
and '@'
in format strings: if a special character follows a '%'
character, it is treated as a plain character. In other words, "%%"
is considered as a plain '%'
and "%@"
as a plain '@'
.
For more information about conversion specifications and formatting indications available, read the documentation of modules Scanf
, Printf
and Format
.
Format strings have a general and highly polymorphic type ('a, 'b, 'c, 'd, 'e, 'f) format6
. The two simplified types, format
and format4
below are included for backward compatibility with earlier releases of OCaml.
The meaning of format string type parameters is as follows:
'a
is the type of the parameters of the format for formatted output functions (printf
-style functions); 'a
is the type of the values read by the format for formatted input functions (scanf
-style functions).'b
is the type of input source for formatted input functions and the type of output target for formatted output functions. For printf
-style functions from module Printf
, 'b
is typically out_channel
; for printf
-style functions from module Format
, 'b
is typically Format.formatter
; for scanf
-style functions from module Scanf
, 'b
is typically Scanf
.Scanning.in_channel.Type argument 'b
is also the type of the first argument given to user's defined printing functions for %a
and %t
conversions, and user's defined reading functions for %r
conversion.
'c
is the type of the result of the %a
and %t
printing functions, and also the type of the argument transmitted to the first argument of kprintf
-style functions or to the kscanf
-style functions.'d
is the type of parameters for the scanf
-style functions.'e
is the type of the receiver function for the scanf
-style functions.'f
is the final result type of a formatted input/output function invocation: for the printf
-style functions, it is typically unit
; for the scanf
-style functions, it is typically the result type of the receiver function.type ('a, 'b, 'c, 'd, 'e, 'f) format6 =
('a, 'b, 'c, 'd, 'e, 'f) CamlinternalFormatBasics.format6
type ('a, 'b, 'c, 'd) format4 = ('a, 'b, 'c, 'c, 'c, 'd) format6
type ('a, 'b, 'c) format = ('a, 'b, 'c, 'c) format4
val string_of_format : ('a, 'b, 'c, 'd, 'e, 'f) format6 -> string
Converts a format string into a string.
format_of_string s
returns a format string read from the string literal s
. Note: format_of_string
can not convert a string argument that is not a literal. If you need this functionality, use the more general Scanf
.format_from_string function.
val (^^) :
('a, 'b, 'c, 'd, 'e, 'f) format6 ->
('f, 'b, 'c, 'e, 'g, 'h) format6 ->
('a, 'b, 'c, 'd, 'g, 'h) format6
f1 ^^ f2
catenates format strings f1
and f2
. The result is a format string that behaves as the concatenation of format strings f1
and f2
: in case of formatted output, it accepts arguments from f1
, then arguments from f2
; in case of formatted input, it returns results from f1
, then results from f2
. Right-associative operator, see Ocaml_operators
for more information.