Module Stdlib

Raise the given exception value

A faster version raise which does not record the backtrace.

Raise exception Invalid_argument with the given string.

Raise exception Failure with the given string.

The Exit exception is not raised by any library function. It is provided for use in your programs.

protect ~finally work invokes work () and then finally () before work returns with its value or an exception. In the latter case the exception is re-raised after finally (). If finally () raises, this exception is not caught and may shadow one work () may have raised.

e1 = 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 raises Invalid_argument. Equality between cyclic data structures may not terminate. Left-associative operator with precedence level below (@) and above (&&).

Negation of (=). Left-associative operator with the same precedence level as (=), below (@) and above (&&).

See (>=). Left-associative operator with the same precedence level as (=), below (@) and above (&&).

See (>=). Left-associative operator with the same precedence level as (=), below (@) and above (&&).

See (>=). Left-associative operator with the same precedence level as (=), below (@) and above (&&).

Structural ordering functions. These functions coincide with the usual orderings over integers, characters, strings, byte sequences and floating-point numbers, and extend them to a total ordering over all types. The ordering is compatible with ( = ). As in the case of ( = ), mutable structures are compared by contents. Comparison between functional values raises Invalid_argument. Comparison between cyclic structures may not terminate. Left-associative operator with the same precedence level as (=), below (@) and above (&&).

compare x y returns 0 if x is equal to y, a negative integer if x is less than y, and a positive integer if x is greater than y. The ordering implemented by compare is compatible with the comparison predicates =, < and > defined above, with one difference on the treatment of the float value nan. Namely, the comparison predicates treat nan as different from any other float value, including itself; while compare treats nan as equal to itself and less than any other float value. This treatment of nan ensures that compare defines a total ordering relation.

compare applied to functional values may raise Invalid_argument. compare applied to cyclic structures may not terminate.

The compare function can be used as the comparison function required by the Set.Make and Map.Make functors, as well as the List.sort and Array.sort functions.

Return the smaller of the two arguments. The result is unspecified if one of the arguments contains the float value nan.

Return the greater of the two arguments. The result is unspecified if one of the arguments contains the float value nan.

e1 == e2 tests for physical equality of e1 and e2. On mutable types such as references, arrays, byte sequences, records with mutable fields and objects with mutable instance variables, e1 == e2 is true if and only if physical modification of e1 also affects e2. On non-mutable types, the behavior of ( == ) is implementation-dependent; however, it is guaranteed that e1 == e2 implies compare e1 e2 = 0. Left-associative operator with the same precedence level as (=), below (@) and above (&&).

Negation of (==). Left-associative operator with the same precedence level as (=), below (@) and above (&&).

The boolean negation.

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 with precedence below (=) and above (||).

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 with precedence below (&&) and above (:=).

__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".

__FILE__ returns the name of the file currently being parsed by the compiler.

__LINE__ returns the line number at which this expression appears in the file currently being parsed by the compiler.

__MODULE__ returns the module name of the file 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 with the same precedence level as (=), below (@) and above (&&).

Application operator: g @@ f @@ x is exactly equivalent to g (f (x)). Right-associative operator with the same precedence as (@), below (::) and above (=).

Unary negation. You can also write - e instead of ~- e. Unary operator with either the same precedence level as (!) for ~- e, above method call and function application, or below function application for - e.

Unary addition. You can also write + e instead of ~+ e. Unary operator with either the same precedence level as (!) for ~+ e, above method call and function application, or below function application for + e.

succ x is x + 1.

pred x is x - 1.

Integer addition. Left-associative operator with precedence level below ( * ) and above (@).

Integer subtraction. Left-associative operator with the same precedence level as (+), below ( * ) and above (@).

Integer multiplication. Left-associative operator with precedence level below ( ** ) and above (+).

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 with the same precedence as ( * ), below ( ** ) and above (+).

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 with the same precedence as ( * ), below ( ** ) and above (+).

Return the absolute value of the argument. Note that this may be negative if the argument is min_int.

The greatest representable integer.

The smallest representable integer.

Bitwise logical and. Left-associative operator with the same precedence as ( * ), below ( ** ) and above (+).

Bitwise logical or. Left-associative operator with the same precedence as ( * ), below ( ** ) and above (+).

Bitwise logical exclusive or. Left-associative operator with the same precedence as ( * ), below ( ** ) and above (+).

Bitwise logical negation.

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 with the same precedence as ( ** ), below (~-) and above ( * ).

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 with the same precedence as ( ** ), below (~-) and above ( * ).

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 with the same precedence as ( ** ), below (~-) and above ( * ).

Unary negation. You can also write -. e instead of ~-. e. Unary operator with either the same precedence level as (!) for ~-.e, above method call and function application, or below function application for -.e.

Unary addition. You can also write +. e instead of ~+. e. Unary operator with either the same precedence level as (!) for ~+.e, above method call and function application, or below function application for +.e.

Floating-point addition. Left-associative operator with the same precedence level as (+), below ( * ) and above (=).

Floating-point subtraction. Left-associative operator with the same precedence level as (+), below ( * ) and above (=).

Floating-point multiplication. Left-associative operator with the same precedence level as ( * ), below ( ** ) and above (+).

Floating-point division. Left-associative operator with the same precedence level as ( * ), below ( ** ) and above (+).

Exponentiation. Right-associative operator with precedence level below (~-) and above ( * ).

Square root.

Exponential.

Natural logarithm.

Base 10 logarithm.

expm1 x computes exp x -. 1.0, giving numerically-accurate results even if x is close to 0.0.

log1p x computes log(1.0 +. x) (natural logarithm), giving numerically-accurate results even if x is close to 0.0.

Cosine. Argument is in radians.

Sine. Argument is in radians.

Tangent. Argument is in radians.

Arc cosine. The argument must fall within the range [-1.0, 1.0]. Result is in radians and is between 0.0 and pi.

Arc sine. The argument must fall within the range [-1.0, 1.0]. Result is in radians and is between -pi/2 and pi/2.

Arc tangent. Result is in radians and is between -pi/2 and pi/2.

atan2 y x returns the arc tangent of y /. x. The signs of x and y are used to determine the quadrant of the result. Result is in radians and is between -pi and pi.

hypot x y returns sqrt(x *. x + y *. y), that is, the length of the hypotenuse of a right-angled triangle with sides of length x and y, or, equivalently, the distance of the point (x,y) to origin. If one of x or y is infinite, returns infinity even if the other is nan.

Hyperbolic cosine. Argument is in radians.

Hyperbolic sine. Argument is in radians.

Hyperbolic tangent. Argument is in radians.

Round above to an integer value. ceil f returns the least integer value greater than or equal to f. The result is returned as a float.

Round below to an integer value. floor f returns the greatest integer value less than or equal to f. The result is returned as a float.

abs_float f returns the absolute value of f.

copysign x y returns a float whose absolute value is that of x and whose sign is that of y. If x is nan, returns nan. If y is nan, returns either x or -. x, but it is not specified which.

mod_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.

frexp 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.

ldexp x n returns x *. 2 ** n.

modf f returns the pair of the fractional and integral part of f.

Same as float_of_int.

Convert an integer to floating-point.

Same as int_of_float.

Truncate the given floating-point number to an integer. The result is unspecified if the argument is nan or falls outside the range of representable integers.

Positive infinity.

Negative infinity.

A special floating-point value denoting the result of an undefined operation such as 0.0 /. 0.0. Stands for 'not a number'. Any floating-point operation with nan as argument returns nan as result. As for floating-point comparisons, =, <, <=, > and >= return false and <> returns true if one or both of their arguments is nan.

The largest positive finite value of type float.

The smallest positive, non-zero, non-denormalized value of type float.

The difference between 1.0 and the smallest exactly representable floating-point number greater than 1.0.

The five classes of floating-point numbers, as determined by the classify_float function.

Return the class of the given floating-point number: normal, subnormal, zero, infinite, or not a number.

String concatenation. Right-associative operator with the same precedence level as (@), below (::) and above (=).

Return the ASCII code of the argument.

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".

Same as bool_of_string_opt, but raise Invalid_argument "bool_of_string" instead of returning None.

Return the string representation of an integer, in decimal.

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.

Same as int_of_string_opt, but raise Failure "int_of_string" instead of returning None.

Return the string representation of a floating-point number.

Convert the given string to a float. The string is read in decimal (by default) or in hexadecimal (marked by 0x or 0X).

The format of decimal floating-point numbers is [-] dd.ddd (e|E) [+|-] dd , where d stands for a decimal digit.

The format of hexadecimal floating-point numbers is [-] 0(x|X) hh.hhh (p|P) [+|-] dd , where h stands for an hexadecimal digit and d for a decimal digit.

In both cases, at least one of the integer and fractional parts must be given; the exponent part is optional.

The _ (underscore) character can appear anywhere in the string and is ignored.

Depending on the execution platforms, other representations of floating-point numbers can be accepted, but should not be relied upon.

Return None if the given string is not a valid representation of a float.

Same as float_of_string_opt, but raise Failure "float_of_string" instead of returning None.

Return the first component of a pair.

Return the second component of a pair.

List concatenation. Not tail-recursive (length of the first argument). Right-associative operator with precedence level below (::) and above (=).

The type of input channel.

The type of output channel.

The standard input for the process.

The standard output for the process.

The standard error output for the process.

Print a character on standard output.

Print a string on standard output.

Print a byte sequence on standard output.

Print an integer, in decimal, on standard output.

Print a floating-point number, in decimal, on standard output.

Print a string, followed by a newline character, on standard output and flush standard output.

Print a newline character on standard output, and flush standard output. This can be used to simulate line buffering of standard output.

Print a character on standard error.

Print a string on standard error.

Print a byte sequence on standard error.

Print an integer, in decimal, on standard error.

Print a floating-point number, in decimal, on standard error.

Print a string, followed by a newline character on standard error and flush standard error.

Print a newline character on standard error, and flush standard error.

Flush standard output, then read characters from standard input until a newline character is encountered. Return the string of all characters read, without the newline character at the end.

Flush standard output, then read one line from standard input and convert it to an integer.

Return None if the line read is not a valid representation of an integer.

Same as read_int_opt, but raise Failure "int_of_string" instead of returning None.

Flush standard output, then read one line from standard input and convert it to a floating-point number.

Return None if the line read is not a valid representation of a floating-point number.

Same as read_float_opt, but raise Failure "float_of_string" instead of returning None.

Opening modes for open_out_gen and open_in_gen.

Open the named file for writing, and return a new output channel on that file, positioned at the beginning of the file. The file is truncated to zero length if it already exists. It is created if it does not already exists.

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.

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. open_out and open_out_bin are special cases of this function.

Flush the buffer associated with the given output channel, performing all pending writes on that channel. Interactive programs must be careful about flushing standard output and standard error at the right time.

Flush all open output channels; ignore errors.

Write the character on the given output channel.

Write the string on the given output channel.

Write the byte sequence on the given output channel.

output oc buf pos len writes len characters from byte sequence buf, starting at offset pos, to the given output channel oc. Raise Invalid_argument "output" if pos and len do not designate a valid range of buf.

Same as output but take a string as argument instead of a byte sequence.

Write one 8-bit integer (as the single character with that code) on the given output channel. The given integer is taken modulo 256.

Write one integer in binary format (4 bytes, big-endian) on the given output channel. The given integer is taken modulo 2³². The only reliable way to read it back is through the input_binary_int function. The format is compatible across all machines for a given version of OCaml.

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.to_channel with an empty list of flags.

seek_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.

Return the current writing position for the given channel. Does not work on channels opened with the Open_append flag (returns unspecified results).

Return the size (number of characters) of the regular file on which the given channel is opened. If the channel is opened on a file that is not a regular file, the result is meaningless.

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. Note that close_out may raise Sys_error if the operating system signals an error when flushing or closing.

Same as close_out, but ignore all errors.

set_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.

Open the named file for reading, and return a new input channel on that file, positioned at the beginning of the file.

Same as 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 open_in.

open_in_gen 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. open_in and open_in_bin are special cases of this function.

Read one character from the given input channel. Raise End_of_file if there are no more characters to read.

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.

input ic buf pos len reads up to len characters from the given channel ic, storing them in byte sequence 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 really_input for reading exactly len characters.) Exception Invalid_argument "input" is raised if pos and len do not designate a valid range of buf.

really_input ic buf pos len reads len characters from channel ic, storing them in byte sequence 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 range of buf.

really_input_string ic len reads len characters from channel ic and returns them in a new string. Raise End_of_file if the end of file is reached before len characters have been read.

Same as input_char, but return the 8-bit integer representing the character. Raise End_of_file if an end of file was reached.

Read an integer encoded in binary format (4 bytes, big-endian) from the given input channel. See output_binary_int. Raise End_of_file if an end of file was reached while reading the integer.

Read the representation of a structured value, as produced by 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.

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.

Return the current reading position for the given channel.

Return the size (number of characters) of the regular file on which the given channel is opened. If the channel is opened on a file that is not a regular file, the result is meaningless. The returned size does not take into account the end-of-line translations that can be performed when reading from a channel opened in text mode.

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.

Same as close_in, but ignore all errors.

set_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.

The type of references (mutable indirection cells) containing a value of type 'a.

Return a fresh reference containing the given value.

!r returns the current contents of reference r. Equivalent to fun r -> r.contents. Unary operator with precedence level above method and function calls

r := a stores the value of a in reference r. Equivalent to fun r v -> r.contents <- v. Right-associative operator with precedence level below (||) and (&&).

Increment the integer contained in the given reference. Equivalent to fun r -> r := succ !r.

Decrement the integer contained in the given reference. Equivalent to fun r -> r := pred !r.

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.

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 with the same precedence level as (@), below (::) and above (=).

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. All open output channels are flushed with flush_all. An implicit exit 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.

Register the given function to be called at program termination time. The functions registered with at_exit will be called when the program does any of the following:

• executes exit
• terminates, either normally or because of an uncaught exception
• executes the C function caml_shutdown. The functions are called in 'last in, first out' order: the function most recently added with at_exit is called first.