192 lines
10 KiB
OCaml
192 lines
10 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. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Module [Str]: regular expressions and high-level string processing *)
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(*** 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 syntax for regular expressions
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is the same as in Gnu Emacs. The special characters are
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[$^.*+?[]]. The following constructs are recognized:
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- [. ] matches any character except newline
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- [* ] (postfix) matches the previous expression zero, one or
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several times
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- [+ ] (postfix) matches the previous expression one or
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several times
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- [? ] (postfix) matches the previous expression once or
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not at all
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- [[..] ] character set; ranges are denoted with [-], as in [[a-z]];
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an initial [^], as in [[^0-9]], complements the set
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- [^ ] matches at beginning of line
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- [$ ] matches at end of line
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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, etc)
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- [\b ] matches word boundaries
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- [\ ] quotes special characters. *)
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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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val regexp_string_case_fold: 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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[Str.regexp_string_case_fold] is similar, but the regexp
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matches in a case-insensitive way. *)
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(*** String matching and searching *)
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external string_match: pat:regexp -> string -> pos:int -> bool
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= "str_string_match"
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(* [string_match r s start] tests whether the characters in [s]
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starting at position [start] match the regular expression [r].
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The first character of a string has position [0], as usual. *)
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external search_forward: pat:regexp -> string -> pos:int -> int
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= "str_search_forward"
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(* [search_forward r s start] searchs 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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external search_backward: pat:regexp -> string -> pos:int -> int
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= "str_search_backward"
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(* Same as [search_forward], but the search proceeds towards the
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beginning of the string. *)
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external string_partial_match: pat:regexp -> string -> pos:int -> bool
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= "str_string_partial_match"
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(* Similar to [string_match], but succeeds whenever the argument
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string is a prefix of a string that matches. This includes
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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 [string_match], [search_forward] or [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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val match_end: 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 [string_match],
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[search_forward] or [search_backward]. [match_end()] returns
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the position of the character following the last character of
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the matched substring. *)
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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 [string_match], [search_forward] or [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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val group_end: 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. [group_end n] returns
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the position of the character following the last character of
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the matched substring. Both functions raise [Not_found]
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if the [n]th group of the regular expression
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was not matched. *)
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(*** Replacement *)
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val global_replace: pat:regexp -> templ: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: pat:regexp -> templ:string -> string -> string
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(* Same as [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:
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pat:regexp -> subst:(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:
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pat:regexp -> subst:(string -> string) -> string -> string
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(* Same as [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 : templ: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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(*** Splitting *)
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val split: sep: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: sep:regexp -> string -> max:int -> string list
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(* Same as [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: sep:regexp -> string -> string list
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val bounded_split_delim: sep:regexp -> string -> max:int -> string list
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(* Same as [split] and [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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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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type split_result = Text of string | Delim of string
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val full_split: sep:regexp -> string -> split_result list
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val bounded_full_split: sep:regexp -> string -> int -> split_result list
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(* Same as [split_delim] and [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]. For instance,
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[full_split (regexp "[{}]") "{ab}"] returns
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[[Delim "{"; Text "ab"; Delim "}"]]. *)
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(*** 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 -> len: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 [string_before]. *)
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val last_chars: string -> len:int -> string
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(* [last_chars s n] returns the last [n] characters of [s]. *)
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