Standard Library
Below is the API for the OCaml standard library. It's directly copied over from the OCaml Manual, formatted to the Reason syntax and styled accordingly. The API docs are work-in-progress; we'll be polishing these gradually!
If you're targeting JavaScript, the API docs for BuckleScript includes all of below, plus JS-specific APIs.
Module StringLabels
module StringLabels: sig .. endval length : string -> int
val get : string -> int -> char
String.get s n returns the character at index n in string s.
You can also write s.[n] instead of String.get s n.
Raise Invalid_argument if n not a valid index in s.
val set : bytes -> int -> char -> unit
BytesLabels.set.String.set s n c modifies byte sequence s in place,
replacing the byte at index n with c.
You can also write s.[n] <- c instead of String.set s n c.
Raise Invalid_argument if n is not a valid index in s.
val create : int -> bytes
BytesLabels.create.String.create n returns a fresh byte sequence of length n.
The sequence is uninitialized and contains arbitrary bytes.
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 init : int -> f:(int -> char) -> string
init n f returns a string of length n,
with character i initialized to the result of f i.
Raise Invalid_argument if n < 0 or n > Sys.max_string_length.
val copy : string -> string
val sub : string -> pos:int -> len: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 : bytes -> pos:int -> len:int -> char -> unit
BytesLabels.fill.String.fill s start len c modifies byte sequence s in place,
replacing len bytes by c, starting at start.
Raise Invalid_argument if start and len do not
designate a valid substring of s.
val blit : src:string -> src_pos:int -> dst:bytes -> dst_pos:int -> len:int -> unit
String.blit src srcoff dst dstoff len copies len bytes
from the string src, starting at index srcoff,
to byte sequence dst, starting at character number dstoff.
Raise Invalid_argument if srcoff and len do not
designate a valid range of src, or if dstoff and len
do not designate a valid range of dst.
val concat : sep:string -> string list -> string
String.concat sep sl concatenates the list of strings sl,
inserting the separator string sep between each.val iter : f:(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 iteri : f:(int -> char -> unit) -> string -> unit
String.iter, but the
function is applied to the index of the element as first argument
(counting from 0), and the character itself as second argument.Since 4.00.0
val map : f:(char -> char) -> string -> string
String.map f s applies function f in turn to all
the characters of s and stores the results in a new string that
is returned.Since 4.00.0
val mapi : f:(int -> char -> char) -> string -> string
String.mapi f s calls f with each character of s and its
index (in increasing index order) and stores the results in a new
string that is returned.Since 4.02.0
val trim : string -> string
' ',
'\012', '\n', '\r', and '\t'. If there is no leading nor
trailing whitespace character in the argument, return the original
string itself, not a copy.Since 4.00.0
val escaped : string -> string
val index : string -> char -> int
String.index s c returns the index 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 index 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 index 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 index 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
val lowercase : string -> string
val capitalize : string -> string
val uncapitalize : string -> string
type t = string
val compare : t -> t -> int
Pervasives.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.