Substring.t is the type of substrings of a basestring, an efficient representation of a piece of a string.
A substring (s,i,n) is valid if 0 <= i <= i+n <= size s, or equivalently, 0 <= i and 0 <= n and i+n <= size s.
A valid substring (s, i, n) represents the string si...i+n-1.
Invariant in the implementation: Any value of type Substring.t is valid.
val empty : unit -> tval to_string : t -> stringstring sus is the string si..i+n-1 represented by sus = (s, i, n).
val of_string : string -> tval make : int -> char -> tval create : int -> tval of_input : BatIO.input -> tval substring : string -> int -> int -> tsubstring s o l returns a substring with base-string s, offset o and length l. Arguments are checked for validity
substring s i n creates the substring (s, i, n), consisting of the substring of s with length n starting at i.
val unsafe_substring : string -> int -> int -> tunsafe_substring behaves like substring, but does not perform any sanity check on the position and length.
val extract : string -> int -> int option -> textract s i None creates the substring (s, i, size s-i) consisting of the tail of s starting at i.
val all : string -> tall s is the substring (s, 0, size s).
val base : t -> string * int * intbase sus is the concrete triple (s, i, n), where psus = (s, i,
n).
val is_empty : t -> boolis_empty (s, i, n) true if the substring is empty (that is, n = 0).
getc sus returns Some(c, rst) where c is the first character and rst the remainder of sus, if sus is non-empty; otherwise returns None.
val first : t -> char optionfirst sus returns Some c where c is the first character in sus, if sus is non-empty; otherwise returns None.
triml k sus returns sus less its leftmost k characters; or the empty string at the end of sus if it has less than k characters.
trimr k sus returns sus less its rightmost k characters; or the empty string at the beginning of sus if it has less than k characters.
val get : t -> int -> charget sus k returns the k'th character of the substring; that is, s(i+k) where sus = (s, i, n).
val size : t -> intsize (s, i, n) returns the size of the substring, that is, n.
slice sus i' None returns the substring (s, i+i', n-i'), where sus = (s, i, n).
val concat : t list -> stringconcat suss returns a string consisting of the concatenation of the substrings. Equivalent to String.concat (List.map to_string
suss).
val explode : t -> char listexplode sus returns the list of characters of sus, that is, s(i), s(i+1), ..., s(i+n-1) where sus = (s, i, n). Equivalent to String.explode (to_string ss).
val is_prefix : string -> t -> boolis_prefix s1 s2 is true if s1 is a prefix of s2. That is, if there exists a string t such that string s1 ^ t = to_string s2.
compare sus1 sus2 performs lexicographic comparison, using the standard ordering Char.compare on the characters.p Equivalent to, but more efficient than, String.compare (to_string sus1)
(to_string sus2).
val index : t -> char -> intindex sus c returns the index of the first occurrence of c in sus or
val index_from : t -> int -> char -> intindex_from sus i c returns the index of the first occurrence of c in sus after the index i or
val rindex : t -> char -> intrindex sus c returns the index of the last occurrence of c in sus or
val rindex_from : t -> int -> char -> intindex_from sus i c returns the index of the last occurrence of c in sus before the index i or
val contains : t -> char -> boolcontains s c tests if character c appears in the substring s.
dropl p sus drops the longest prefix (left substring) of sus all of whose characters satisfy predicate p. If all characters do, it returns the empty substring (s, i+n, 0) where sus = (s, i, n).
dropr p sus drops the longest suffix (right substring) of sus all of whose characters satisfy predicate p. If all characters do, it returns the empty substring (s, i, 0) where sus = (s, i, n).
takel p sus returns the longest prefix (left substring) of sus all of whose characters satisfy predicate p. That is, if the left-most character does not satisfy p, returns the empty (s, i, 0) where sus = (s, i, n).
taker p sus returns the longest suffix (right substring) of sus all of whose characters satisfy predicate p. That is, if the right-most character satisfies p, returns the empty (s, i+n, 0) where sus = (s, i, n).
Let p be a predicate and xxxxfyyyyfzzzz a string where all characters in xxxx and zzzz satisfy p, and f a character not satisfying p. Then
sus = xxxxfyyyyfzzzz sus = xxxxzzzz ------------------------------------------------------ dropl p sus = fyyyyfzzzz dropr p sus = xxxxfyyyyf takel p sus = xxxx xxxxzzzz taker p sus = zzzz xxxxzzzz
It also holds that concat (takel p sus) (dropl p sus) = string sus concat (dropr p sus) (taker p sus) = string sus
splitl p sus splits sus into a pair (sus1, sus2) of substrings where sus1 is the longest prefix (left substring) all of whose characters satisfy p, and sus2 is the rest. That is, sus2 begins with the leftmost character not satisfying p. Disregarding sideeffects, we have: splitl p sus = (takel p sus,
dropl p sus).
splitr p sus splits sus into a pair (sus1, sus2) of substrings where sus2 is the longest suffix (right substring) all of whose characters satisfy p, and sus1 is the rest. That is, sus1 ends with the rightmost character not satisfying p. Disregarding sideeffects, we have: splitr p sus = (dropr p sus,
taker p sus)
split_at sus k returns the pair (sus1, sus2) of substrings, where sus1 contains the first k characters of sus, and sus2 contains the rest.
span sus1 sus2 returns a substring spanning from the start of sus1 to the end of sus2, provided this is well-defined: sus1 and sus2 must have the same underlying string, and the start of sus1 must not be to the right of the end of sus2; otherwise
val translate : (char -> char) -> t -> stringtranslate f sus applies f to every character of sus, from left to right, and returns the concatenation of the results. Equivalent to String.of_list (List.map f (explode sus)).
tokens p sus returns the list of tokens in sus, from left to right, where a token is a non-empty maximal substring of sus not containing any delimiter, and a delimiter is a character satisfying p.
fields p sus returns the list of fields in sus, from left to right, where a field is a (possibly empty) maximal substring of sus not containing any delimiter, and a delimiter is a character satisfying p.
Two tokens may be separated by more than one delimiter, whereas two fields are separated by exactly one delimiter. If the only delimiter is the character '|', then "abc||def" contains two tokens: "abc" and "def" "abc||def" contains three fields: "abc" and "" and "def"
val fold_left : ('a -> char -> 'a) -> 'a -> t -> 'afold_left f e sus folds f over sus from left to right. That is, evaluates f s.[i+n-1] (f ... (f s.[i+1] (f s.[i] e)) ...) tail-recursively, where sus = (s, i, n). Equivalent to List.fold_left f e (explode sus).
val fold_lefti : ('a -> int -> char -> 'a) -> 'a -> t -> 'aAs fold_left, but with the index of the element as additional argument
val fold_right : (char -> 'a -> 'a) -> t -> 'a -> 'afold_right f e sus folds f over sus from right to left. That is, evaluates f s.[i] (f s.[i+1] (f ... (f s.[i+n-1] e) ...)) tail-recursively, where sus = (s, i, n). Equivalent to List.fold_right f e (explode sus).
val fold_righti : (int -> char -> 'a -> 'a) -> t -> 'a -> 'aAs fold_right, but with the index of the element as additional argument
val iter : (char -> unit) -> t -> unititer f sus applies f to all characters of sus, from left to right. Equivalent to List.iter f (explode sus).
val iteri : (int -> char -> unit) -> t -> unitSame as 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.
split_on_char c ss returns substrings of input ss as divided by c
enum ss returns an enumeration of the characters represented by ss. It does no copying so beweare of mutating the original string.
val print : 'a BatIO.output -> t -> unitprint oc ss prints ss to the output channel oc