249 lines
11 KiB
OCaml
249 lines
11 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License, with *)
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(* the special exception on linking described in file ../../LICENSE. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(** Regular expressions and high-level string processing *)
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(** {6 Regular expressions} *)
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type regexp
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(** The type of compiled regular expressions. *)
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val regexp : string -> regexp
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(** Compile a regular expression. The following constructs are
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recognized:
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- [. ] Matches any character except newline.
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- [* ] (postfix) Matches the preceding expression zero, one or
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several times
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- [+ ] (postfix) Matches the preceding expression one or
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several times
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- [? ] (postfix) Matches the preceding expression once or
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not at all
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- [[..] ] Character set. Ranges are denoted with [-], as in [[a-z]].
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An initial [^], as in [[^0-9]], complements the set.
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To include a [\]] character in a set, make it the first
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character of the set. To include a [-] character in a set,
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make it the first or the last character of the set.
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- [^ ] Matches at beginning of line (either at the beginning of
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the matched string, or just after a newline character).
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- [$ ] Matches at end of line (either at the end of the matched
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string, or just before a newline character).
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- [\| ] (infix) Alternative between two expressions.
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- [\(..\)] Grouping and naming of the enclosed expression.
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- [\1 ] The text matched by the first [\(...\)] expression
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([\2] for the second expression, and so on up to [\9]).
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- [\b ] Matches word boundaries.
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- [\ ] Quotes special characters. The special characters
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are [$^.*+?[]].
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*)
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val regexp_case_fold : string -> regexp
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(** Same as [regexp], but the compiled expression will match text
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in a case-insensitive way: uppercase and lowercase letters will
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be considered equivalent. *)
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val quote : string -> string
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(** [Str.quote s] returns a regexp string that matches exactly
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[s] and nothing else. *)
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val regexp_string : string -> regexp
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(** [Str.regexp_string s] returns a regular expression
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that matches exactly [s] and nothing else.*)
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val regexp_string_case_fold : string -> regexp
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(** [Str.regexp_string_case_fold] is similar to {!Str.regexp_string},
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but the regexp matches in a case-insensitive way. *)
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(** {6 String matching and searching} *)
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val string_match : regexp -> string -> int -> bool
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(** [string_match r s start] tests whether a substring of [s] that
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starts at position [start] matches the regular expression [r].
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The first character of a string has position [0], as usual. *)
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val search_forward : regexp -> string -> int -> int
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(** [search_forward r s start] searches the string [s] for a substring
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matching the regular expression [r]. The search starts at position
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[start] and proceeds towards the end of the string.
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Return the position of the first character of the matched
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substring, or raise [Not_found] if no substring matches. *)
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val search_backward : regexp -> string -> int -> int
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(** [search_backward r s last] searches the string [s] for a
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substring matching the regular expression [r]. The search first
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considers substrings that start at position [last] and proceeds
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towards the beginning of string. Return the position of the first
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character of the matched substring; raise [Not_found] if no
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substring matches. *)
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val string_partial_match : regexp -> string -> int -> bool
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(** Similar to {!Str.string_match}, but also returns true if
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the argument string is a prefix of a string that matches.
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This includes the case of a true complete match. *)
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val matched_string : string -> string
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(** [matched_string s] returns the substring of [s] that was matched
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by the latest {!Str.string_match}, {!Str.search_forward} or
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{!Str.search_backward}.
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The user must make sure that the parameter [s] is the same string
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that was passed to the matching or searching function. *)
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val match_beginning : unit -> int
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(** [match_beginning()] returns the position of the first character
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of the substring that was matched by {!Str.string_match},
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{!Str.search_forward} or {!Str.search_backward}. *)
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val match_end : unit -> int
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(** [match_end()] returns the position of the character following the
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last character of the substring that was matched by [string_match],
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[search_forward] or [search_backward]. *)
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val matched_group : int -> string -> string
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(** [matched_group n s] returns the substring of [s] that was matched
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by the [n]th group [\(...\)] of the regular expression during
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the latest {!Str.string_match}, {!Str.search_forward} or
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{!Str.search_backward}.
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The user must make sure that the parameter [s] is the same string
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that was passed to the matching or searching function.
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[matched_group n s] raises [Not_found] if the [n]th group
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of the regular expression was not matched. This can happen
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with groups inside alternatives [\|], options [?]
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or repetitions [*]. For instance, the empty string will match
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[\(a\)*], but [matched_group 1 ""] will raise [Not_found]
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because the first group itself was not matched. *)
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val group_beginning : int -> int
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(** [group_beginning n] returns the position of the first character
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of the substring that was matched by the [n]th group of
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the regular expression.
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@raise Not_found if the [n]th group of the regular expression
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was not matched.
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@raise Invalid_argument if there are fewer than [n] groups in
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the regular expression. *)
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val group_end : int -> int
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(** [group_end n] returns
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the position of the character following the last character of
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substring that was matched by the [n]th group of the regular expression.
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@raise Not_found if the [n]th group of the regular expression
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was not matched.
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@raise Invalid_argument if there are fewer than [n] groups in
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the regular expression. *)
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(** {6 Replacement} *)
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val global_replace : regexp -> string -> string -> string
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(** [global_replace regexp templ s] returns a string identical to [s],
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except that all substrings of [s] that match [regexp] have been
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replaced by [templ]. The replacement template [templ] can contain
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[\1], [\2], etc; these sequences will be replaced by the text
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matched by the corresponding group in the regular expression.
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[\0] stands for the text matched by the whole regular expression. *)
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val replace_first : regexp -> string -> string -> string
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(** Same as {!Str.global_replace}, except that only the first substring
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matching the regular expression is replaced. *)
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val global_substitute : regexp -> (string -> string) -> string -> string
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(** [global_substitute regexp subst s] returns a string identical
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to [s], except that all substrings of [s] that match [regexp]
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have been replaced by the result of function [subst]. The
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function [subst] is called once for each matching substring,
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and receives [s] (the whole text) as argument. *)
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val substitute_first : regexp -> (string -> string) -> string -> string
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(** Same as {!Str.global_substitute}, except that only the first substring
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matching the regular expression is replaced. *)
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val replace_matched : string -> string -> string
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(** [replace_matched repl s] returns the replacement text [repl]
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in which [\1], [\2], etc. have been replaced by the text
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matched by the corresponding groups in the most recent matching
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operation. [s] must be the same string that was matched during
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this matching operation. *)
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(** {6 Splitting} *)
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val split : regexp -> string -> string list
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(** [split r s] splits [s] into substrings, taking as delimiters
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the substrings that match [r], and returns the list of substrings.
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For instance, [split (regexp "[ \t]+") s] splits [s] into
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blank-separated words. An occurrence of the delimiter at the
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beginning and at the end of the string is ignored. *)
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val bounded_split : regexp -> string -> int -> string list
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(** Same as {!Str.split}, but splits into at most [n] substrings,
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where [n] is the extra integer parameter. *)
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val split_delim : regexp -> string -> string list
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(** Same as {!Str.split} but occurrences of the
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delimiter at the beginning and at the end of the string are
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recognized and returned as empty strings in the result.
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For instance, [split_delim (regexp " ") " abc "]
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returns [[""; "abc"; ""]], while [split] with the same
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arguments returns [["abc"]]. *)
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val bounded_split_delim : regexp -> string -> int -> string list
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(** Same as {!Str.bounded_split}, but occurrences of the
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delimiter at the beginning and at the end of the string are
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recognized and returned as empty strings in the result. *)
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type split_result =
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Text of string
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| Delim of string
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val full_split : regexp -> string -> split_result list
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(** Same as {!Str.split_delim}, but returns
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the delimiters as well as the substrings contained between
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delimiters. The former are tagged [Delim] in the result list;
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the latter are tagged [Text]. For instance,
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[full_split (regexp "[{}]") "{ab}"] returns
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[[Delim "{"; Text "ab"; Delim "}"]]. *)
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val bounded_full_split : regexp -> string -> int -> split_result list
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(** Same as {!Str.bounded_split_delim}, but returns
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the delimiters as well as the substrings contained between
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delimiters. The former are tagged [Delim] in the result list;
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the latter are tagged [Text]. *)
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(** {6 Extracting substrings} *)
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val string_before : string -> int -> string
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(** [string_before s n] returns the substring of all characters of [s]
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that precede position [n] (excluding the character at
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position [n]). *)
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val string_after : string -> int -> string
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(** [string_after s n] returns the substring of all characters of [s]
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that follow position [n] (including the character at
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position [n]). *)
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val first_chars : string -> int -> string
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(** [first_chars s n] returns the first [n] characters of [s].
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This is the same function as {!Str.string_before}. *)
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val last_chars : string -> int -> string
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(** [last_chars s n] returns the last [n] characters of [s]. *)
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