Module Pcre

module Pcre: sig .. end
Perl Compatibility Regular Expressions


Exceptions

type error = 
| Partial (*
String only matched the pattern partially
*)
| BadPartial (*
Pattern contains items that cannot be used together with partial matching.
*)
| BadPattern of string * int (*
BadPattern (msg, pos) regular expression is malformed. The reason is in msg, the position of the error in the pattern in pos.
*)
| BadUTF8 (*
UTF8 string being matched is invalid
*)
| BadUTF8Offset (*
Gets raised when a UTF8 string being matched with offset is invalid.
*)
| MatchLimit (*
Maximum allowed number of match attempts with backtracking or recursion is reached during matching. ALL FUNCTIONS CALLING THE MATCHING ENGINE MAY RAISE IT!!!
*)
| RecursionLimit
| InternalError of string (*
InternalError msg C-library exhibits unknown/undefined behaviour. The reason is in msg.
*)
exception Error of error
Exception indicating PCRE errors.
exception Backtrack
Backtrack used in callout functions to force backtracking.
exception Regexp_or of string * error
Regexp_or (pat, error) gets raised for sub-pattern pat by regexp_or if it failed to compile.

Compilation and runtime flags and their conversion functions

type icflag 
Internal representation of compilation flags
type irflag 
Internal representation of runtime flags
type cflag = [ `ANCHORED
| `AUTO_CALLOUT
| `CASELESS
| `DOLLAR_ENDONLY
| `DOTALL
| `EXTENDED
| `EXTRA
| `FIRSTLINE
| `MULTILINE
| `NO_AUTO_CAPTURE
| `NO_UTF8_CHECK
| `UNGREEDY
| `UTF8 ]
Compilation flags
val cflags : cflag list -> icflag
cflags cflag_list converts a list of compilation flags to their internal representation.
val cflag_list : icflag -> cflag list
cflag_list cflags converts internal representation of compilation flags to a list.
type rflag = [ `ANCHORED | `NOTBOL | `NOTEMPTY | `NOTEOL | `PARTIAL ] 
Runtime flags
val rflags : rflag list -> irflag
rflags rflag_list converts a list of runtime flags to their internal representation.
val rflag_list : irflag -> rflag list
rflag_list rflags converts internal representation of runtime flags to a list.

Information on the PCRE-configuration (build-time options)

val version : string
Version information

Version of the PCRE-C-library

val config_utf8 : bool
Indicates whether UTF8-support is enabled
val config_newline : char
Character used as newline
val config_link_size : int
Number of bytes used for internal linkage of regular expressions
val config_match_limit : int
Default limit for calls to internal matching function
val config_match_limit_recursion : int
Default limit recursion for calls to internal matching function
val config_stackrecurse : bool
Indicates use of stack recursion in matching function

Information on patterns

type firstbyte_info = [ `ANCHORED | `Char of char | `Start_only ] 
Information on matching of "first chars" in patterns
type study_stat = [ `Not_studied | `Optimal | `Studied ] 
Information on the study status of patterns
type regexp 
Compiled regular expressions
val options : regexp -> icflag
options regexp
Returns compilation flags of regexp.
val size : regexp -> int
size regexp
Returns memory size of regexp.
val studysize : regexp -> int
studysize regexp
Returns memory size of study information of regexp.
val capturecount : regexp -> int
capturecount regexp
Returns number of capturing subpatterns in regexp.
val backrefmax : regexp -> int
backrefmax regexp
Returns number of highest backreference in regexp.
val namecount : regexp -> int
namecount regexp
Returns number of named subpatterns in regexp.
val names : regexp -> string array
names regex
Returns array of names of named substrings in regexp.
val nameentrysize : regexp -> int
nameentrysize regexp
Returns size of longest name of named subpatterns in regexp + 3.
val firstbyte : regexp -> firstbyte_info
firstbyte regexp
Returns firstbyte info on regexp.
val firsttable : regexp -> string option
firsttable regexp
Returns some 256-bit (32-byte) fixed set table in form of a string for regexp if available, None otherwise.
val lastliteral : regexp -> char option
lastliteral regexp
Returns some last matching character of regexp if available, None otherwise.
val study_stat : regexp -> study_stat
study_stat regexp
Returns study status of regexp.
val get_stringnumber : regexp -> string -> int
get_stringnumber rex name
Raises Invalid_arg if there is no such named substring.
Returns the index of the named substring name in regular expression rex. This index can then be used with get_substring.
val get_match_limit : regexp -> int option
get_match_limit rex
Returns some match limit of regular expression rex or None.
val get_match_limit_recursion : regexp -> int option
get_match_limit_recursion rex
Returns some recursion match limit of regular expression rex or None.

Compilation of patterns

type chtables 
Alternative set of char tables for pattern matching
val maketables : unit -> chtables
Generates new set of char tables for the current locale.
val regexp : ?study:bool ->
?limit:int ->
?limit_recursion:int ->
?iflags:icflag ->
?flags:cflag list -> ?chtables:chtables -> string -> regexp
regexp ?study ?limit ?limit_recursion ?iflags ?flags ?chtables pattern compiles pattern with flags when given, with iflags otherwise, and with char tables chtables. If study is true, then the resulting regular expression will be studied. If limit is specified, this sets a limit to the amount of recursion and backtracking (only lower than the builtin default!). If this limit is exceeded, MatchLimit will be raised during matching.
Returns the regular expression.

For detailed documentation on how you can specify PERL-style regular expressions (= patterns), please consult the PCRE-documentation ("man pcrepattern") or PERL-manuals.
See also www.perl.com

study : default = true
limit : default = no extra limit other than default
limit_recursion : default = no extra limit_recursion other than default
iflags : default = no extra flags
flags : default = ignored
chtables : default = builtin char tables
val regexp_or : ?study:bool ->
?limit:int ->
?limit_recursion:int ->
?iflags:icflag ->
?flags:cflag list ->
?chtables:chtables -> string list -> regexp
regexp_or ?study ?limit ?limit_recursion ?iflags ?flags ?chtables patterns like Pcre.regexp, but combines patterns as alternatives (or-patterns) into one regular expression.
val quote : string -> string
quote str
Returns the quoted string of str.

Subpattern extraction

type substrings 
Information on substrings after pattern matching
val get_subject : substrings -> string
get_subject substrings
Returns the subject string of substrings.
val num_of_subs : substrings -> int
num_of_subs substrings
Returns number of strings in substrings (whole match inclusive).
val get_substring : substrings -> int -> string
get_substring substrings n
Raises Returns the nth substring (0 is whole match) of substrings.
val get_substring_ofs : substrings -> int -> int * int
get_substring_ofs substrings n
Raises Returns the offset tuple of the nth substring of substrings (0 is whole match).
val get_substrings : ?full_match:bool -> substrings -> string array
get_substrings ?full_match substrings
Returns the array of substrings in substrings. It includes the full match at index 0 when full_match is true, the captured substrings only when it is false. If a subpattern did not capture a substring, the empty string is returned in the corresponding position instead.
full_match : default = true
val get_opt_substrings : ?full_match:bool -> substrings -> string option array
get_opt_substrings ?full_match substrings
Returns the array of optional substrings in substrings. It includes Some full_match_str at index 0 when full_match is true, Some captured_substrings only when it is false. If a subpattern did not capture a substring, None is returned in the corresponding position instead.
full_match : default = true
val get_named_substring : regexp -> string -> substrings -> string
get_named_substring rex name substrings
Raises Returns the named substring name in regular expression rex and substrings.
val get_named_substring_ofs : regexp -> string -> substrings -> int * int
get_named_substring_ofs rex name substrings
Raises Returns the offset tuple of the named substring name in regular expression rex and substrings.

Callouts

type callout_data = {
   callout_number : int; (*
Callout number
*)
   substrings : substrings; (*
Substrings matched so far
*)
   start_match : int; (*
Subject start offset of current match attempt
*)
   current_position : int; (*
Subject offset of current match pointer
*)
   capture_top : int; (*
Number of the highest captured substring so far
*)
   capture_last : int; (*
Number of the most recently captured substring
*)
   pattern_position : int; (*
Offset of next match item in pattern string
*)
   next_item_length : int; (*
Length of next match item in pattern string
*)
}
type callout = callout_data -> unit 
Type of callout functions

Callouts are referred to in patterns as "(?Cn)" where "n" is a callout_number ranging from 0 to 255. Substrings captured so far are accessible as usual via substrings. You will have to consider capture_top and capture_last to know about the current state of valid substrings.

By raising exception Backtrack within a callout function, the user can force the pattern matching engine to backtrack to other possible solutions. Other exceptions will terminate matching immediately and return control to OCaml.


Matching of patterns and subpattern extraction

val pcre_exec : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string -> ?pos:int -> ?callout:callout -> string -> int array
pcre_exec ?iflags ?flags ?rex ?pat ?pos ?callout subj
Raises Not_found if pattern does not match.
Returns an array of offsets that describe the position of matched subpatterns in the string subj starting at position pos with pattern pat when given, regular expression rex otherwise. The array also contains additional workspace needed by the match engine. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val exec : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string -> ?pos:int -> ?callout:callout -> string -> substrings
exec ?iflags ?flags ?rex ?pat ?pos ?callout subj
Raises Not_found if pattern does not match.
Returns substring information on string subj starting at position pos with pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val exec_all : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int -> ?callout:callout -> string -> substrings array
exec_all ?iflags ?flags ?rex ?pat ?pos ?callout subj
Raises Not_found if pattern does not match.
Returns an array of substring information of all matching substrings in string subj starting at position pos with pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val next_match : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int -> ?callout:callout -> substrings -> substrings
next_match ?iflags ?flags ?rex ?pat ?pos ?callout substrs
Raises Returns substring information on the match that follows on the last match denoted by substrs, jumping over pos characters (also backwards!), using pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val extract : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?full_match:bool -> ?callout:callout -> string -> string array
extract ?iflags ?flags ?rex ?pat ?pos ?full_match ?callout subj
Raises Not_found if pattern does not match.
Returns the array of substrings that match subj starting at position pos, using pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. It includes the full match at index 0 when full_match is true, the captured substrings only when it is false. Callouts are handled by callout. If a subpattern did not capture a substring, the empty string is returned in the corresponding position instead.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
full_match : default = true
callout : default = ignore callouts
val extract_opt : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?full_match:bool -> ?callout:callout -> string -> string option array
extract_opt ?iflags ?flags ?rex ?pat ?pos ?full_match ?callout subj
Raises Not_found if pattern does not match.
Returns the array of optional substrings that match subj starting at position pos, using pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. It includes Some full_match_str at index 0 when full_match is true, Some captured-substrings only when it is false. Callouts are handled by callout. If a subpattern did not capture a substring, None is returned in the corresponding position instead.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
full_match : default = true
callout : default = ignore callouts
val extract_all : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?full_match:bool -> ?callout:callout -> string -> string array array
extract_all ?iflags ?flags ?rex ?pat ?pos ?full_match ?callout subj
Raises Not_found if pattern does not match.
Returns an array of arrays of all matching substrings that match subj starting at position pos, using pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. It includes the full match at index 0 of the extracted string arrays when full_match is true, the captured substrings only when it is false. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
full_match : default = true
callout : default = ignore callouts
val extract_all_opt : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?full_match:bool ->
?callout:callout -> string -> string option array array
extract_all_opt ?iflags ?flags ?rex ?pat ?pos ?full_match ?callout subj
Raises Not_found if pattern does not match.
Returns an array of arrays of all optional matching substrings that match subj starting at position pos, using pattern pat when given, regular expression rex otherwise. Uses flags when given, the precompiled iflags otherwise. It includes Some full_match_str at index 0 of the extracted string arrays when full_match is true, Some captured_substrings only when it is false. Callouts are handled by callout. If a subpattern did not capture a substring, None is returned in the corresponding position instead.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
full_match : default = true
callout : default = ignore callouts
val pmatch : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string -> ?pos:int -> ?callout:callout -> string -> bool
pmatch ?iflags ?flags ?rex ?pat ?pos ?callout subj
Returns true if subj is matched by pattern pat when given, regular expression rex otherwise, starting at position pos. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts

String substitution

type substitution 
Information on substitution patterns
val subst : string -> substitution
subst str converts the string str representing a substitution pattern to the internal representation

The contents of the substitution string str can be normal text mixed with any of the following (mostly as in PERL):


val replace : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?itempl:substitution ->
?templ:string -> ?callout:callout -> string -> string
replace ?iflags ?flags ?rex ?pat ?pos ?itempl ?templ ?callout subj replaces all substrings of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the substitution string templ when given, itempl otherwise. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
Raises Failure if there are backreferences to nonexistent subpatterns.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
itempl : default = empty string
templ : default = ignored
callout : default = ignore callouts
val qreplace : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int -> ?templ:string -> ?callout:callout -> string -> string
qreplace ?iflags ?flags ?rex ?pat ?pos ?templ ?callout subj replaces all substrings of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the string templ. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
templ : default = ignored
callout : default = ignore callouts
val substitute_substrings : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?callout:callout ->
subst:(substrings -> string) -> string -> string
substitute_substrings ?iflags ?flags ?rex ?pat ?pos ?callout ~subst subj replaces all substrings of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the result of function subst applied to the substrings of the match. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val substitute : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?callout:callout -> subst:(string -> string) -> string -> string
substitute ?iflags ?flags ?rex ?pat ?pos ?callout ~subst subj replaces all substrings of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the result of function subst applied to the match. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val replace_first : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?itempl:substitution ->
?templ:string -> ?callout:callout -> string -> string
replace_first ?iflags ?flags ?rex ?pat ?pos ?itempl ?templ ?callout subj replaces the first substring of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the substitution string templ when given, itempl otherwise. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
Raises Failure if there are backreferences to nonexistent subpatterns.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
itempl : default = empty string
templ : default = ignored
callout : default = ignore callouts
val qreplace_first : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int -> ?templ:string -> ?callout:callout -> string -> string
qreplace_first ?iflags ?flags ?rex ?pat ?pos ?templ ?callout subj replaces the first substring of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the string templ. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
templ : default = ignored
callout : default = ignore callouts
val substitute_substrings_first : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?callout:callout ->
subst:(substrings -> string) -> string -> string
substitute_substrings_first ?iflags ?flags ?rex ?pat ?pos ?callout ~subst subj replaces the first substring of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the result of function subst applied to the substrings of the match. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts
val substitute_first : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?callout:callout -> subst:(string -> string) -> string -> string
substitute_first ?iflags ?flags ?rex ?pat ?pos ?callout ~subst subj replaces the first substring of subj matching pattern pat when given, regular expression rex otherwise, starting at position pos with the result of function subst applied to the match. Uses flags when given, the precompiled iflags otherwise. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
callout : default = ignore callouts

Splitting

val split : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int -> ?max:int -> ?callout:callout -> string -> string list
split ?iflags ?flags ?rex ?pat ?pos ?max ?callout subj splits subj into a list of at most max strings, using as delimiter pattern pat when given, regular expression rex otherwise, starting at position pos. Uses flags when given, the precompiled iflags otherwise. If max is zero, trailing empty fields are stripped. If it is negative, it is treated as arbitrarily large. If neither pat nor rex are specified, leading whitespace will be stripped! Should behave exactly as in PERL. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
max : default = 0
callout : default = ignore callouts
val asplit : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int -> ?max:int -> ?callout:callout -> string -> string array
asplit ?iflags ?flags ?rex ?pat ?pos ?max ?callout subj same as Pcre.split but
Returns an array instead of a list.
type split_result = 
| Text of string (*
Text part of split string
*)
| Delim of string (*
Delimiter part of split string
*)
| Group of int * string (*
Subgroup of matched delimiter (subgroup_nr, subgroup_str)
*)
| NoGroup (*
Unmatched subgroup
*)
Result of a Pcre.full_split
val full_split : ?iflags:irflag ->
?flags:rflag list ->
?rex:regexp ->
?pat:string ->
?pos:int ->
?max:int -> ?callout:callout -> string -> split_result list
full_split ?iflags ?flags ?rex ?pat ?pos ?max ?callout subj splits subj into a list of at most max elements of type "split_result", using as delimiter pattern pat when given, regular expression rex otherwise, starting at position pos. Uses flags when given, the precompiled iflags otherwise. If max is zero, trailing empty fields are stripped. If it is negative, it is treated as arbitrarily large. Should behave exactly as in PERL. Callouts are handled by callout.
iflags : default = no extra flags
flags : default = ignored
rex : default = matches whitespace
pat : default = ignored
pos : default = 0
max : default = 0
callout : default = ignore callouts

Additional convenience functions

val foreach_line : ?ic:Pervasives.in_channel -> (string -> unit) -> unit
foreach_line ?ic f applies f to each line in inchannel ic until the end-of-file is reached.
ic : default = stdin
val foreach_file : string list -> (string -> Pervasives.in_channel -> unit) -> unit
foreach_file filenames f opens each file in the list filenames for input and applies f to each filename and the corresponding channel. Channels are closed after each operation (even when exceptions occur - they get reraised afterwards!).

UNSAFE STUFF - USE WITH CAUTION!

val unsafe_pcre_exec : irflag ->
regexp ->
pos:int ->
subj_start:int -> subj:string -> int array -> callout option -> unit
unsafe_pcre_exec flags rex ~pos ~subj_start ~subj offset_vector. You should read the C-source to know what happens. If you do not understand it - don't use this function!
val make_ovector : regexp -> int * int array
make_ovector regexp calculates the tuple (subgroups2, ovector) which is the number of subgroup offsets and the offset array.