Module Char.Ascii

ASCII character set support.

These functions give meaning to the integers [0x00;0x7F] of the ASCII character set.

Since the UTF-8 encoding of Unicode has the same encoding and character semantics (U+0000 to U+001F) for these bytes, the functions can be safely used on elements of UTF-8 encoded string and bytes values. However the functions only deal with ASCII related matters. For example the notion of Unicode whitespace is much larger than the ASCII whitespace determined by Char.Ascii.is_white.

since 5.4

Characters

val min : char

let min: char;

min is '\x00'.

val max : char

let max: char;

max is '\x7F'.

Predicates

val is_valid : char -> bool

let is_valid: char => bool;

is_valid c is true if and only if c is an ASCII character, that is a byte in the range [min;max].

val is_upper : char -> bool

let is_upper: char => bool;

is_upper c is true if and only if c is an ASCII uppercase letter 'A' to 'Z', that is a byte in the range [0x41;0x5A].

val is_lower : char -> bool

let is_lower: char => bool;

is_lower c is true if and only if c is an ASCII lowercase letter 'a' to 'z', that is a byte in the range [0x61;0x7A].

val is_letter : char -> bool

let is_letter: char => bool;

is_letter c is is_lowerc ||is_upper c.

val is_alphanum : char -> bool

let is_alphanum: char => bool;

is_alphanum c is is_letterc ||is_digit c.

val is_white : char -> bool

let is_white: char => bool;

is_white c is true if and only if c is an ASCII white space character, that is one of tab '\t' (0x09), newline '\n' (0x0A), vertical tab (0x0B), form feed (0x0C), carriage return '\r' (0x0D) or space ' ' (0x20),

val is_blank : char -> bool

let is_blank: char => bool;

is_blank c is true if and only if c is an ASCII blank character, that is either space ' ' (0x20) or tab '\t' (0x09).

val is_graphic : char -> bool

let is_graphic: char => bool;

is_graphic c is true if and only if c is an ASCII graphic character, that is a byte in the range [0x21;0x7E].

val is_print : char -> bool

let is_print: char => bool;

is_print c is is_graphic c || c = ' '.

val is_control : char -> bool

let is_control: char => bool;

is_control c is true if and only if c is an ASCII control character, that is a byte in the range [0x00;0x1F] or 0x7F.

Decimal digits

val is_digit : char -> bool

let is_digit: char => bool;

is_digit c is true if and only if c is an ASCII decimal digit '0' to '9', that is a byte in the range [0x30;0x39].

val digit_to_int : char -> int

let digit_to_int: char => int;

digit_to_int c is the numerical value of a digit that satisfies is_digit. Raises Invalid_argument if is_digit c is false.

val digit_of_int : int -> char

let digit_of_int: int => char;

digit_of_int n is an ASCII decimal digit for the decimal value abs (n mod 10).

Hexadecimal digits

val is_hex_digit : char -> bool

let is_hex_digit: char => bool;

is_hex_digit c is true if and only if c is an ASCII hexadecimal digit '0' to '9', 'a' to 'f' or 'A' to 'F', that is a byte in one of the ranges [0x30;0x39], [0x41;0x46], [0x61;0x66].

val hex_digit_to_int : char -> int

let hex_digit_to_int: char => int;

hex_digit_to_int c is the numerical value of a digit that satisfies is_hex_digit. Raises Invalid_argument if is_hex_digit c is false.

val lower_hex_digit_of_int : int -> char

let lower_hex_digit_of_int: int => char;

lower_hex_digit_of_int n is a lowercase ASCII hexadecimal digit for the hexadecimal value abs (n mod 16).

val upper_hex_digit_of_int : int -> char

let upper_hex_digit_of_int: int => char;

upper_hex_digit_of_int n is an uppercase ASCII hexadecimal digit for the hexadecimal value abs (n mod 16).

Casing transforms

val uppercase : char -> char

let uppercase: char => char;

uppercase c is c with ASCII characters 'a' to 'z' respectively mapped to uppercase characters 'A' to 'Z'. Other characters are left untouched.

val lowercase : char -> char

let lowercase: char => char;

lowercase c is c with ASCII characters 'A' to 'Z' respectively mapped to lowercase characters 'a' to 'z'. Other characters are left untouched.