stdune
Library
Module
Module type
Parameter
Class
Class type
include module type of struct include StringLabels end with type t := t
Strings
make n c
is a string of length n
with each index holding the character c
.
init n ~f
is a string of length n
with index i
holding the character f i
(called in increasing index order).
get s i
is the character at index i
in s
. This is the same as writing s.[i]
.
Concatenating
Note. The Stdlib.(^)
binary operator concatenates two strings.
concat ~sep ss
concatenates the list of strings ss
, inserting the separator string sep
between each.
Predicates and comparisons
contains_from s start c
is true
if and only if c
appears in s
after position start
.
rcontains_from s stop c
is true
if and only if c
appears in s
before position stop+1
.
contains s c
is String.contains_from
s 0 c
.
Extracting substrings
sub s ~pos ~len
is a string of length len
, containing the substring of s
that starts at position pos
and has length len
.
split_on_char ~sep s
is the list of all (possibly empty) substrings of s
that are delimited by the character sep
.
The function's result is specified by the following invariants:
- The list is not empty.
- Concatenating its elements using
sep
as a separator returns a string equal to the input (concat (make 1 sep) (split_on_char sep s) = s
). - No string in the result contains the
sep
character.
Transforming
map f s
is the string resulting from applying f
to all the characters of s
in increasing order.
mapi ~f s
is like map
but the index of the character is also passed to f
.
trim s
is s
without leading and trailing whitespace. Whitespace characters are: ' '
, '\x0C'
(form feed), '\n'
, '\r'
, and '\t'
.
escaped s
is s
with special characters represented by escape sequences, following the lexical conventions of OCaml.
All characters outside the US-ASCII printable range [0x20;0x7E] are escaped, as well as backslash (0x2F) and double-quote (0x22).
The function Scanf.unescaped
is a left inverse of escaped
, i.e. Scanf.unescaped (escaped s) = s
for any string s
(unless escaped s
fails).
uppercase_ascii s
is s
with all lowercase letters translated to uppercase, using the US-ASCII character set.
lowercase_ascii s
is s
with all uppercase letters translated to lowercase, using the US-ASCII character set.
capitalize_ascii s
is s
with the first character set to uppercase, using the US-ASCII character set.
uncapitalize_ascii s
is s
with the first character set to lowercase, using the US-ASCII character set.
Traversing
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.[length s - 1]; ()
.
iteri
is like iter
, but the function is also given the corresponding character index.
Searching
index_from_opt s i c
is the index of the first occurrence of c
in s
after position i
(if any).
rindex_from_opt s i c
is the index of the last occurrence of c
in s
before position i+1
(if any).
index_opt s c
is String.index_from_opt
s 0 c
.
rindex_opt s c
is String.rindex_from_opt
s (length s - 1) c
.
Converting
to_seq s
is a sequence made of the string's characters in increasing order. In "unsafe-string"
mode, modifications of the string during iteration will be reflected in the iterator.
to_seqi s
is like to_seq
but also tuples the corresponding index.
Deprecated functions
create n
returns a fresh byte sequence of length n
. The sequence is uninitialized and contains arbitrary bytes.
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 set s n c
.
blit ~src ~src_pos ~dst ~dst_pos ~len
copies len
bytes from the string src
, starting at index src_pos
, to byte sequence dst
, starting at character number dst_pos
.
val compare : t -> t -> Ordering.t
val hash : t -> int
val is_empty : t -> bool
val of_list : char list -> t
val index : t -> char -> int option
val index_from : t -> int -> char -> int option
val rindex : t -> char -> int option
val rindex_from : t -> int -> char -> int option
Escape ONLY one character. escape
also escapes '\n',... and transforms all chars above '~' into '\xxx' which is not suitable for UTF-8 strings.
val exists : t -> f:( char -> bool ) -> bool
val for_all : t -> f:( char -> bool ) -> bool
maybe_quoted s
is s
if s
doesn't need escaping according to OCaml lexing conventions and sprintf "%S" s
otherwise.
(* CR-someday aalekseyev: this function is not great: barely anything "needs escaping according to OCaml lexing conventions", so the condition for whether to add the quote characters ends up being quite arbitrary. *)
quote_for_shell s
quotes s
using Filename.quote
if need_quoting s
is true