Module UTF8

module UTF8: sig .. end

UTF-8 encoded Unicode strings.

The Module for UTF-8 encoded Unicode strings.

type t = string

UTF-8 encoded Unicode strings. the type is normal string.

exception Malformed_code

val validate : t -> unit

validate s Succeeds if s is valid UTF-8, otherwise raises Malformed_code. Other functions assume strings are valid UTF-8, so it is prudent to test their validity for strings from untrusted origins.

val get : t -> int -> UChar.uchar

get s n returns n-th Unicode character of s. The call requires O(n)-time.

val init : int -> (int -> UChar.uchar) -> t

init len f returns a new string which contains len Unicode characters. The i-th Unicode character is initialized by f i

val length : t -> int

length s returns the number of Unicode characters contained in s

type index = int

Positions in the string represented by the number of bytes from the head. The location of the first character is 0

val nth : t -> int -> index

nth s n returns the position of the n-th Unicode character. The call requires O(n)-time

val last : t -> index

The position of the head of the last Unicode character.

val look : t -> index -> UChar.uchar

look s i returns the Unicode character of the location i in the string s.

val out_of_range : t -> index -> bool

out_of_range s i tests whether i is a position inside of s.

val compare_index : t -> index -> index -> int

compare_index s i1 i2 returns a value < 0 if i1 is the position located before i2, 0 if i1 and i2 points the same location, a value > 0 if i1 is the position located after i2.

val next : t -> index -> index

next s i returns the position of the head of the Unicode character located immediately after i. If i is inside of s, the function always successes. If i is inside of s and there is no Unicode character after i, the position outside s is returned. If i is not inside of s, the behaviour is unspecified.

val prev : t -> index -> index

prev s i returns the position of the head of the Unicode character located immediately before i. If i is inside of s, the function always successes. If i is inside of s and there is no Unicode character before i, the position outside s is returned. If i is not inside of s, the behaviour is unspecified.

val move : t -> index -> int -> index

move s i n returns n-th Unicode character after i if n >= 0, n-th Unicode character before i if n < 0. If there is no such character, the result is unspecified.

val iter : (UChar.uchar -> unit) -> t -> unit

iter f s applies f to all Unicode characters in s. The order of application is same to the order of the Unicode characters in s.

val compare : t -> t -> int

Code point comparison by the lexicographic order. compare s1 s2 returns a positive integer if s1 > s2, 0 if s1 = s2, a negative integer if s1 < s2.

module Buf: sig .. end

Buffer module for UTF-8 strings