package omod
Library
Module
Module type
Parameter
Class
Class type
Strings.
include module type of String
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).
Return a new string that contains the same bytes as the given byte sequence.
Return a new byte sequence that contains the same bytes as the given string.
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
compare s0 s1
sorts s0
and s1
in lexicographical order. compare
behaves like Stdlib.compare
on strings but may be more efficient.
starts_with
~prefix s
is true
if and only if s
starts with prefix
.
ends_with
~suffix s
is true
if and only if s
ends with suffix
.
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
.
fold_left f x s
computes f (... (f (f x s.[0]) s.[1]) ...) s.[n-1]
, where n
is the length of the string s
.
fold_right f s x
computes f s.[0] (f s.[1] ( ... (f s.[n-1] x) ...))
, where n
is the length of the string s
.
for_all p s
checks if all characters in s
satisfy the predicate p
.
exists p s
checks if at least one character of s
satisfies the predicate p
.
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 s i c
is the index of the first occurrence of c
in s
after position i
.
index_from_opt s i c
is the index of the first occurrence of c
in s
after position i
(if any).
rindex_from s i c
is the index of the last occurrence of c
in s
before position i+1
.
rindex_from_opt s i c
is the index of the last occurrence of c
in s
before position i+1
(if any).
index s c
is String.index_from
s 0 c
.
index_opt s c
is String.index_from_opt
s 0 c
.
rindex s c
is String.rindex_from
s (length s - 1) c
.
rindex_opt s c
is String.rindex_from_opt
s (length s - 1) c
.
Strings and Sequences
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 sequence.
to_seqi s
is like to_seq
but also tuples the corresponding index.
UTF decoding and validations
UTF-8
val get_utf_8_uchar : t -> int -> Uchar.utf_decode
get_utf_8_uchar b i
decodes an UTF-8 character at index i
in b
.
val is_valid_utf_8 : t -> bool
is_valid_utf_8 b
is true
if and only if b
contains valid UTF-8 data.
UTF-16BE
val get_utf_16be_uchar : t -> int -> Uchar.utf_decode
get_utf_16be_uchar b i
decodes an UTF-16BE character at index i
in b
.
val is_valid_utf_16be : t -> bool
is_valid_utf_16be b
is true
if and only if b
contains valid UTF-16BE data.
UTF-16LE
val get_utf_16le_uchar : t -> int -> Uchar.utf_decode
get_utf_16le_uchar b i
decodes an UTF-16LE character at index i
in b
.
val is_valid_utf_16le : t -> bool
is_valid_utf_16le b
is true
if and only if b
contains valid UTF-16LE data.
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
.
fill s pos len c
modifies byte sequence s
in place, replacing len
bytes by c
, starting at pos
.
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.
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.
Return a copy of the argument, with the first character set to uppercase, using the ISO Latin-1 (8859-1) character set..
Return a copy of the argument, with the first character set to lowercase, using the ISO Latin-1 (8859-1) character set.
Binary decoding of integers
The functions in this section binary decode integers from strings.
All following functions raise Invalid_argument
if the characters needed at index i
to decode the integer are not available.
Little-endian (resp. big-endian) encoding means that least (resp. most) significant bytes are stored first. Big-endian is also known as network byte order. Native-endian encoding is either little-endian or big-endian depending on Sys.big_endian
.
32-bit and 64-bit integers are represented by the int32
and int64
types, which can be interpreted either as signed or unsigned numbers.
8-bit and 16-bit integers are represented by the int
type, which has more bits than the binary encoding. These extra bits are sign-extended (or zero-extended) for functions which decode 8-bit or 16-bit integers and represented them with int
values.
get_uint8 b i
is b
's unsigned 8-bit integer starting at character index i
.
get_int8 b i
is b
's signed 8-bit integer starting at character index i
.
get_uint16_ne b i
is b
's native-endian unsigned 16-bit integer starting at character index i
.
get_uint16_be b i
is b
's big-endian unsigned 16-bit integer starting at character index i
.
get_uint16_le b i
is b
's little-endian unsigned 16-bit integer starting at character index i
.
get_int16_ne b i
is b
's native-endian signed 16-bit integer starting at character index i
.
get_int16_be b i
is b
's big-endian signed 16-bit integer starting at character index i
.
get_int16_le b i
is b
's little-endian signed 16-bit integer starting at character index i
.
get_int32_ne b i
is b
's native-endian 32-bit integer starting at character index i
.
get_int32_be b i
is b
's big-endian 32-bit integer starting at character index i
.
get_int32_le b i
is b
's little-endian 32-bit integer starting at character index i
.
get_int64_ne b i
is b
's native-endian 64-bit integer starting at character index i
.
get_int64_be b i
is b
's big-endian 64-bit integer starting at character index i
.
cut ~sep s
cuts s
on the left and right of the first char sep
starting from the left.
rev_cut ~sep s
cuts s
on the left and right of the first char sep
starting from the right.
edit_distance s0 s1
is the number of single character edits (insertion, deletion, substitution) that are needed to change s0
into s1
.
suggest ~dist candidates s
are the elements of candidates
whose edit distance is the smallest to s
and at most at a distance of dist
of s
(defaults to 2
). If multiple results are returned the order of candidates
is preserved.