Module String

module String: sig .. end

String operations. Given a string s of length l, we call character number in s the index of a character in s. Indexes start at 0, and we will call a character number valid in s if it falls within the range [0...l-1]. A position is the point between two characters or at the beginning or end of the string. We call a position valid in s if it falls within the range [0...l]. Note that character number n is between positions n and n+1.

Two parameters start and len are said to designate a valid substring of s if len >= 0 and start and start+len are valid positions in s.

val length : string -> int

Return the length (number of characters) of the given string.

val get : string -> int -> char

String.get s n returns character number n in string s. You can also write s.[n] instead of String.get s n.

Raise Invalid_argument if n not a valid character number in s.

val set : string -> int -> char -> unit

String.set s n c modifies string s in place, replacing the character number n by c. You can also write s.[n] <- c instead of String.set s n c.

Raise Invalid_argument if n is not a valid character number in s.

val create : int -> string

String.create n returns a fresh string of length n. The string initially contains arbitrary characters.

Raise Invalid_argument if n < 0 or n > Sys.max_string_length.

val make : int -> char -> string

String.make n c returns a fresh string of length n, filled with the character c.

Raise Invalid_argument if n < 0 or n > Sys.max_string_length.

val copy : string -> string

Return a copy of the given string.

val sub : string -> int -> int -> string

String.sub s start len returns a fresh string of length len, containing the substring of s that starts at position start and has length len.

Raise Invalid_argument if start and len do not designate a valid substring of s.

val fill : string -> int -> int -> char -> unit

String.fill s start len c modifies string s in place, replacing len characters by c, starting at start.

Raise Invalid_argument if start and len do not designate a valid substring of s.

val blit : string -> int -> string -> int -> int -> unit

String.blit src srcoff dst dstoff len copies len characters from string src, starting at character number srcoff, to string dst, starting at character number dstoff. It works correctly even if src and dst are the same string, and the source and destination intervals overlap.

Raise Invalid_argument if srcoff and len do not designate a valid substring of src, or if dstoff and len do not designate a valid substring of dst.

val concat : string -> string list -> string

String.concat sep sl concatenates the list of strings sl, inserting the separator string sep between each.

val iter : (char -> unit) -> string -> unit

String.iter f s applies function f in turn to all the characters of s. It is equivalent to f s.[0]; f s.[1]; ...; f s.[String.length s - 1]; ().

val escaped : string -> string

Return a copy of the argument, with special characters represented by escape sequences, following the lexical conventions of Objective Caml. If there is no special character in the argument, return the original string itself, not a copy.

val index : string -> char -> int

String.index s c returns the character number of the first occurrence of character c in string s.

Raise Not_found if c does not occur in s.

val rindex : string -> char -> int

String.rindex s c returns the character number of the last occurrence of character c in string s.

Raise Not_found if c does not occur in s.

val index_from : string -> int -> char -> int

String.index_from s i c returns the character number of the first occurrence of character c in string s after position i. String.index s c is equivalent to String.index_from s 0 c.

Raise Invalid_argument if i is not a valid position in s. Raise Not_found if c does not occur in s after position i.

val rindex_from : string -> int -> char -> int

String.rindex_from s i c returns the character number of the last occurrence of character c in string s before position i+1. String.rindex s c is equivalent to String.rindex_from s (String.length s - 1) c.

Raise Invalid_argument if i+1 is not a valid position in s. Raise Not_found if c does not occur in s before position i+1.

val contains : string -> char -> bool

String.contains s c tests if character c appears in the string s.

val contains_from : string -> int -> char -> bool

String.contains_from s start c tests if character c appears in s after position start. String.contains s c is equivalent to String.contains_from s 0 c.

Raise Invalid_argument if start is not a valid position in s.

val rcontains_from : string -> int -> char -> bool

String.rcontains_from s stop c tests if character c appears in s before position stop+1.

Raise Invalid_argument if stop < 0 or stop+1 is not a valid position in s.

val uppercase : string -> string

Return a copy of the argument, with all lowercase letters translated to uppercase, including accented letters of the ISO Latin-1 (8859-1) character set.

val lowercase : string -> string

Return a copy of the argument, with all uppercase letters translated to lowercase, including accented letters of the ISO Latin-1 (8859-1) character set.

val capitalize : string -> string

Return a copy of the argument, with the first character set to uppercase.

val uncapitalize : string -> string

Return a copy of the argument, with the first character set to lowercase.

type t = string

An alias for the type of strings.

val compare : t -> t -> int

The comparison function for strings, with the same specification as compare. Along with the type t, this function compare allows the module String to be passed as argument to the functors Set.Make and Map.Make.