/[pcre]/code/trunk/doc/pcre.txt

Diff of /code/trunk/doc/pcre.txt

Parent Directory | Revision Log | View Patch Patch

-revision 155 by ph10,
Tue Apr 24 13:36:11 2007 UTC
+revision 172 by ph10,
Tue Jun  5 10:40:13 2007 UTC
 Line 610 
 THE ALTERNATIVE MATCHING ALGORITHM
         ence  as  the  condition or test for a specific group recursion are not
         supported.
-. Callouts are supported, but the value of the  capture_top  field  is
+. Because many paths through the tree may be  active,  the  \K  escape
+        sequence, which resets the start of the match when encountered (but may
+        be on some paths and not on others), is not  supported.  It  causes  an
+        error if encountered.
+.  Callouts  are  supported, but the value of the capture_top field is
         always 1, and the value of the capture_last field is always -1.
 .  The \C escape sequence, which (in the standard algorithm) matches a
-        single byte, even in UTF-8 mode, is not supported because the  alterna-
+        single  byte, even in UTF-8 mode, is not supported because the alterna-
-        tive  algorithm  moves  through  the  subject string one character at a
+        tive algorithm moves through the subject  string  one  character  at  a
         time, for all active paths through the tree.
  ADVANTAGES OF THE ALTERNATIVE ALGORITHM
-        Using the alternative matching algorithm provides the following  advan-
+        Using  the alternative matching algorithm provides the following advan-
         tages:
 . All possible matches (at a single point in the subject) are automat-
-        ically found, and in particular, the longest match is  found.  To  find
+        ically  found,  and  in particular, the longest match is found. To find
         more than one match using the standard algorithm, you have to do kludgy
         things with callouts.
-. There is much better support for partial matching. The  restrictions
+.  There is much better support for partial matching. The restrictions
-        on  the content of the pattern that apply when using the standard algo-
+        on the content of the pattern that apply when using the standard  algo-
-        rithm for partial matching do not apply to the  alternative  algorithm.
+        rithm  for  partial matching do not apply to the alternative algorithm.
-        For  non-anchored patterns, the starting position of a partial match is
+        For non-anchored patterns, the starting position of a partial match  is
         available.
-. Because the alternative algorithm  scans  the  subject  string  just
+.  Because  the  alternative  algorithm  scans the subject string just
-        once,  and  never  needs to backtrack, it is possible to pass very long
+        once, and never needs to backtrack, it is possible to  pass  very  long
-        subject strings to the matching function in  several  pieces,  checking
+        subject  strings  to  the matching function in several pieces, checking
         for partial matching each time.
-Line 645 
 DISADVANTAGES OF THE ALTERNATIVE ALGORIT
+Line 650 
 DISADVANTAGES OF THE ALTERNATIVE ALGORIT
         The alternative algorithm suffers from a number of disadvantages:
-.  It  is  substantially  slower  than the standard algorithm. This is
+. It is substantially slower than  the  standard  algorithm.  This  is
-        partly because it has to search for all possible matches, but  is  also
+        partly  because  it has to search for all possible matches, but is also
         because it is less susceptible to optimization.
 . Capturing parentheses and back references are not supported.
-Line 664 
 AUTHOR
+Line 669 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 29 May 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 1471 
 INFORMATION ABOUT A PATTERN
+Line 1476 
 INFORMATION ABOUT A PATTERN
         returned. The fourth argument should point to an unsigned char *  vari-
         able.
+          PCRE_INFO_JCHANGED
+        Return  1  if the (?J) option setting is used in the pattern, otherwise
+. The fourth argument should point to an int variable. The (?J) inter-
+        nal option setting changes the local PCRE_DUPNAMES value.
           PCRE_INFO_LASTLITERAL
         Return  the  value of the rightmost literal byte that must exist in any
-Line 1525 
 INFORMATION ABOUT A PATTERN
+Line 1536 
 INFORMATION ABOUT A PATTERN
         name-to-number map, remember that the length of the entries  is  likely
         to be different for each compiled pattern.
+          PCRE_INFO_OKPARTIAL
+        Return  1 if the pattern can be used for partial matching, otherwise 0.
+        The fourth argument should point to an int  variable.  The  pcrepartial
+        documentation  lists  the restrictions that apply to patterns when par-
+        tial matching is used.
           PCRE_INFO_OPTIONS
-        Return  a  copy of the options with which the pattern was compiled. The
+        Return a copy of the options with which the pattern was  compiled.  The
-        fourth argument should point to an unsigned long  int  variable.  These
+        fourth  argument  should  point to an unsigned long int variable. These
         option bits are those specified in the call to pcre_compile(), modified
         by any top-level option settings within the pattern itself.
-        A pattern is automatically anchored by PCRE if  all  of  its  top-level
+        A  pattern  is  automatically  anchored by PCRE if all of its top-level
         alternatives begin with one of the following:
           ^     unless PCRE_MULTILINE is set
-Line 1546 
 INFORMATION ABOUT A PATTERN
+Line 1564 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_SIZE
-        Return the size of the compiled pattern, that is, the  value  that  was
+        Return  the  size  of the compiled pattern, that is, the value that was
         passed as the argument to pcre_malloc() when PCRE was getting memory in
         which to place the compiled data. The fourth argument should point to a
         size_t variable.
-Line 1554 
 INFORMATION ABOUT A PATTERN
+Line 1572 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_STUDYSIZE
         Return the size of the data block pointed to by the study_data field in
-        a pcre_extra block. That is,  it  is  the  value  that  was  passed  to
+        a  pcre_extra  block.  That  is,  it  is  the  value that was passed to
         pcre_malloc() when PCRE was getting memory into which to place the data
-        created by pcre_study(). The fourth argument should point to  a  size_t
+        created  by  pcre_study(). The fourth argument should point to a size_t
         variable.
-Line 1564 
 OBSOLETE INFO FUNCTION
+Line 1582 
 OBSOLETE INFO FUNCTION
         int pcre_info(const pcre *code, int *optptr, int *firstcharptr);
-        The  pcre_info()  function is now obsolete because its interface is too
+        The pcre_info() function is now obsolete because its interface  is  too
-        restrictive to return all the available data about a compiled  pattern.
+        restrictive  to return all the available data about a compiled pattern.
-        New   programs   should  use  pcre_fullinfo()  instead.  The  yield  of
+        New  programs  should  use  pcre_fullinfo()  instead.  The   yield   of
-        pcre_info() is the number of capturing subpatterns, or one of the  fol-
+        pcre_info()  is the number of capturing subpatterns, or one of the fol-
         lowing negative numbers:
           PCRE_ERROR_NULL       the argument code was NULL
           PCRE_ERROR_BADMAGIC   the "magic number" was not found
-        If  the  optptr  argument is not NULL, a copy of the options with which
+        If the optptr argument is not NULL, a copy of the  options  with  which
-        the pattern was compiled is placed in the integer  it  points  to  (see
+        the  pattern  was  compiled  is placed in the integer it points to (see
         PCRE_INFO_OPTIONS above).
-        If  the  pattern  is  not anchored and the firstcharptr argument is not
+        If the pattern is not anchored and the  firstcharptr  argument  is  not
-        NULL, it is used to pass back information about the first character  of
+        NULL,  it is used to pass back information about the first character of
         any matched string (see PCRE_INFO_FIRSTBYTE above).
-Line 1586 
 REFERENCE COUNTS
+Line 1604 
 REFERENCE COUNTS
         int pcre_refcount(pcre *code, int adjust);
-        The  pcre_refcount()  function is used to maintain a reference count in
+        The pcre_refcount() function is used to maintain a reference  count  in
         the data block that contains a compiled pattern. It is provided for the
-        benefit  of  applications  that  operate  in an object-oriented manner,
+        benefit of applications that  operate  in  an  object-oriented  manner,
         where different parts of the application may be using the same compiled
         pattern, but you want to free the block when they are all done.
         When a pattern is compiled, the reference count field is initialized to
-        zero.  It is changed only by calling this function, whose action is  to
+        zero.   It is changed only by calling this function, whose action is to
-        add  the  adjust  value  (which may be positive or negative) to it. The
+        add the adjust value (which may be positive or  negative)  to  it.  The
         yield of the function is the new value. However, the value of the count
-        is  constrained to lie between 0 and 65535, inclusive. If the new value
+        is constrained to lie between 0 and 65535, inclusive. If the new  value
         is outside these limits, it is forced to the appropriate limit value.
-        Except when it is zero, the reference count is not correctly  preserved
+        Except  when it is zero, the reference count is not correctly preserved
-        if  a  pattern  is  compiled on one host and then transferred to a host
+        if a pattern is compiled on one host and then  transferred  to  a  host
         whose byte-order is different. (This seems a highly unlikely scenario.)
-Line 1610 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1628 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
              const char *subject, int length, int startoffset,
              int options, int *ovector, int ovecsize);
-        The  function pcre_exec() is called to match a subject string against a
+        The function pcre_exec() is called to match a subject string against  a
-        compiled pattern, which is passed in the code argument. If the  pattern
+        compiled  pattern, which is passed in the code argument. If the pattern
         has been studied, the result of the study should be passed in the extra
-        argument. This function is the main matching facility of  the  library,
+        argument.  This  function is the main matching facility of the library,
         and it operates in a Perl-like manner. For specialist use there is also
-        an alternative matching function, which is described below in the  sec-
+        an  alternative matching function, which is described below in the sec-
         tion about the pcre_dfa_exec() function.
-        In  most applications, the pattern will have been compiled (and option-
+        In most applications, the pattern will have been compiled (and  option-
-        ally studied) in the same process that calls pcre_exec().  However,  it
+        ally  studied)  in the same process that calls pcre_exec(). However, it
         is possible to save compiled patterns and study data, and then use them
-        later in different processes, possibly even on different hosts.  For  a
+        later  in  different processes, possibly even on different hosts. For a
         discussion about this, see the pcreprecompile documentation.
         Here is an example of a simple call to pcre_exec():
-Line 1640 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1658 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
     Extra data for pcre_exec()
-        If  the  extra argument is not NULL, it must point to a pcre_extra data
+        If the extra argument is not NULL, it must point to a  pcre_extra  data
-        block. The pcre_study() function returns such a block (when it  doesn't
+        block.  The pcre_study() function returns such a block (when it doesn't
-        return  NULL), but you can also create one for yourself, and pass addi-
+        return NULL), but you can also create one for yourself, and pass  addi-
-        tional information in it. The pcre_extra block contains  the  following
+        tional  information  in it. The pcre_extra block contains the following
         fields (not necessarily in this order):
           unsigned long int flags;
-Line 1653 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1671 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           void *callout_data;
           const unsigned char *tables;
-        The  flags  field  is a bitmap that specifies which of the other fields
+        The flags field is a bitmap that specifies which of  the  other  fields
         are set. The flag bits are:
           PCRE_EXTRA_STUDY_DATA
-Line 1662 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1680 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_EXTRA_CALLOUT_DATA
           PCRE_EXTRA_TABLES
-        Other flag bits should be set to zero. The study_data field is  set  in
+        Other  flag  bits should be set to zero. The study_data field is set in
-        the  pcre_extra  block  that is returned by pcre_study(), together with
+        the pcre_extra block that is returned by  pcre_study(),  together  with
         the appropriate flag bit. You should not set this yourself, but you may
-        add  to  the  block by setting the other fields and their corresponding
+        add to the block by setting the other fields  and  their  corresponding
         flag bits.
         The match_limit field provides a means of preventing PCRE from using up
-        a  vast amount of resources when running patterns that are not going to
+        a vast amount of resources when running patterns that are not going  to
-        match, but which have a very large number  of  possibilities  in  their
+        match,  but  which  have  a very large number of possibilities in their
-        search  trees.  The  classic  example  is  the  use of nested unlimited
+        search trees. The classic  example  is  the  use  of  nested  unlimited
         repeats.
-        Internally, PCRE uses a function called match() which it calls  repeat-
+        Internally,  PCRE uses a function called match() which it calls repeat-
-        edly  (sometimes  recursively). The limit set by match_limit is imposed
+        edly (sometimes recursively). The limit set by match_limit  is  imposed
-        on the number of times this function is called during  a  match,  which
+        on  the  number  of times this function is called during a match, which
-        has  the  effect  of  limiting the amount of backtracking that can take
+        has the effect of limiting the amount of  backtracking  that  can  take
         place. For patterns that are not anchored, the count restarts from zero
         for each position in the subject string.
-        The  default  value  for  the  limit can be set when PCRE is built; the
+        The default value for the limit can be set  when  PCRE  is  built;  the
-        default default is 10 million, which handles all but the  most  extreme
+        default  default  is 10 million, which handles all but the most extreme
-        cases.  You  can  override  the  default by suppling pcre_exec() with a
+        cases. You can override the default  by  suppling  pcre_exec()  with  a
-        pcre_extra    block    in    which    match_limit    is    set,     and
+        pcre_extra     block    in    which    match_limit    is    set,    and
-        PCRE_EXTRA_MATCH_LIMIT  is  set  in  the  flags  field. If the limit is
+        PCRE_EXTRA_MATCH_LIMIT is set in the  flags  field.  If  the  limit  is
         exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
-        The match_limit_recursion field is similar to match_limit, but  instead
+        The  match_limit_recursion field is similar to match_limit, but instead
         of limiting the total number of times that match() is called, it limits
-        the depth of recursion. The recursion depth is a  smaller  number  than
+        the  depth  of  recursion. The recursion depth is a smaller number than
-        the  total number of calls, because not all calls to match() are recur-
+        the total number of calls, because not all calls to match() are  recur-
         sive.  This limit is of use only if it is set smaller than match_limit.
-        Limiting  the  recursion  depth  limits the amount of stack that can be
+        Limiting the recursion depth limits the amount of  stack  that  can  be
         used, or, when PCRE has been compiled to use memory on the heap instead
         of the stack, the amount of heap memory that can be used.
-        The  default  value  for  match_limit_recursion can be set when PCRE is
+        The default value for match_limit_recursion can be  set  when  PCRE  is
-        built; the default default  is  the  same  value  as  the  default  for
+        built;  the  default  default  is  the  same  value  as the default for
-        match_limit.  You can override the default by suppling pcre_exec() with
+        match_limit. You can override the default by suppling pcre_exec()  with
-        a  pcre_extra  block  in  which  match_limit_recursion  is   set,   and
+        a   pcre_extra   block  in  which  match_limit_recursion  is  set,  and
-        PCRE_EXTRA_MATCH_LIMIT_RECURSION  is  set  in  the  flags field. If the
+        PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in  the  flags  field.  If  the
         limit is exceeded, pcre_exec() returns PCRE_ERROR_RECURSIONLIMIT.
-        The pcre_callout field is used in conjunction with the  "callout"  fea-
+        The  pcre_callout  field is used in conjunction with the "callout" fea-
         ture, which is described in the pcrecallout documentation.
-        The  tables  field  is  used  to  pass  a  character  tables pointer to
+        The tables field  is  used  to  pass  a  character  tables  pointer  to
-        pcre_exec(); this overrides the value that is stored with the  compiled
+        pcre_exec();  this overrides the value that is stored with the compiled
-        pattern.  A  non-NULL value is stored with the compiled pattern only if
+        pattern. A non-NULL value is stored with the compiled pattern  only  if
-        custom tables were supplied to pcre_compile() via  its  tableptr  argu-
+        custom  tables  were  supplied to pcre_compile() via its tableptr argu-
         ment.  If NULL is passed to pcre_exec() using this mechanism, it forces
-        PCRE's internal tables to be used. This facility is  helpful  when  re-
+        PCRE's  internal  tables  to be used. This facility is helpful when re-
-        using  patterns  that  have been saved after compiling with an external
+        using patterns that have been saved after compiling  with  an  external
-        set of tables, because the external tables  might  be  at  a  different
+        set  of  tables,  because  the  external tables might be at a different
-        address  when  pcre_exec() is called. See the pcreprecompile documenta-
+        address when pcre_exec() is called. See the  pcreprecompile  documenta-
         tion for a discussion of saving compiled patterns for later use.
     Option bits for pcre_exec()
-        The unused bits of the options argument for pcre_exec() must  be  zero.
+        The  unused  bits of the options argument for pcre_exec() must be zero.
-        The  only  bits  that  may  be set are PCRE_ANCHORED, PCRE_NEWLINE_xxx,
+        The only bits that may  be  set  are  PCRE_ANCHORED,  PCRE_NEWLINE_xxx,
         PCRE_NOTBOL,   PCRE_NOTEOL,   PCRE_NOTEMPTY,   PCRE_NO_UTF8_CHECK   and
         PCRE_PARTIAL.
           PCRE_ANCHORED
-        The  PCRE_ANCHORED  option  limits pcre_exec() to matching at the first
+        The PCRE_ANCHORED option limits pcre_exec() to matching  at  the  first
-        matching position. If a pattern was  compiled  with  PCRE_ANCHORED,  or
+        matching  position.  If  a  pattern was compiled with PCRE_ANCHORED, or
-        turned  out to be anchored by virtue of its contents, it cannot be made
+        turned out to be anchored by virtue of its contents, it cannot be  made
         unachored at matching time.
           PCRE_NEWLINE_CR
-Line 1739 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1757 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_NEWLINE_ANYCRLF
           PCRE_NEWLINE_ANY
-        These options override  the  newline  definition  that  was  chosen  or
+        These  options  override  the  newline  definition  that  was chosen or
-        defaulted  when the pattern was compiled. For details, see the descrip-
+        defaulted when the pattern was compiled. For details, see the  descrip-
-        tion of pcre_compile()  above.  During  matching,  the  newline  choice
+        tion  of  pcre_compile()  above.  During  matching,  the newline choice
-        affects  the  behaviour  of the dot, circumflex, and dollar metacharac-
+        affects the behaviour of the dot, circumflex,  and  dollar  metacharac-
-        ters. It may also alter the way the match position is advanced after  a
+        ters.  It may also alter the way the match position is advanced after a
         match  failure  for  an  unanchored  pattern.  When  PCRE_NEWLINE_CRLF,
-        PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a  match  attempt
+        PCRE_NEWLINE_ANYCRLF,  or  PCRE_NEWLINE_ANY is set, and a match attempt
-        fails  when the current position is at a CRLF sequence, the match posi-
+        fails when the current position is at a CRLF sequence, the match  posi-
-        tion is advanced by two characters instead of one, in other  words,  to
+        tion  is  advanced by two characters instead of one, in other words, to
         after the CRLF.
           PCRE_NOTBOL
         This option specifies that first character of the subject string is not
-        the beginning of a line, so the  circumflex  metacharacter  should  not
+        the  beginning  of  a  line, so the circumflex metacharacter should not
-        match  before it. Setting this without PCRE_MULTILINE (at compile time)
+        match before it. Setting this without PCRE_MULTILINE (at compile  time)
-        causes circumflex never to match. This option affects only  the  behav-
+        causes  circumflex  never to match. This option affects only the behav-
         iour of the circumflex metacharacter. It does not affect \A.
           PCRE_NOTEOL
         This option specifies that the end of the subject string is not the end
-        of a line, so the dollar metacharacter should not match it nor  (except
+        of  a line, so the dollar metacharacter should not match it nor (except
-        in  multiline mode) a newline immediately before it. Setting this with-
+        in multiline mode) a newline immediately before it. Setting this  with-
         out PCRE_MULTILINE (at compile time) causes dollar never to match. This
-        option  affects only the behaviour of the dollar metacharacter. It does
+        option affects only the behaviour of the dollar metacharacter. It  does
         not affect \Z or \z.
           PCRE_NOTEMPTY
         An empty string is not considered to be a valid match if this option is
-        set.  If  there are alternatives in the pattern, they are tried. If all
+        set. If there are alternatives in the pattern, they are tried.  If  all
-        the alternatives match the empty string, the entire  match  fails.  For
+        the  alternatives  match  the empty string, the entire match fails. For
         example, if the pattern
           a?b?
-        is  applied  to  a string not beginning with "a" or "b", it matches the
+        is applied to a string not beginning with "a" or "b",  it  matches  the
-        empty string at the start of the subject. With PCRE_NOTEMPTY set,  this
+        empty  string at the start of the subject. With PCRE_NOTEMPTY set, this
         match is not valid, so PCRE searches further into the string for occur-
         rences of "a" or "b".
         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
-        cial  case  of  a  pattern match of the empty string within its split()
+        cial case of a pattern match of the empty  string  within  its  split()
-        function, and when using the /g modifier. It  is  possible  to  emulate
+        function,  and  when  using  the /g modifier. It is possible to emulate
         Perl's behaviour after matching a null string by first trying the match
         again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
-        if  that  fails by advancing the starting offset (see below) and trying
+        if that fails by advancing the starting offset (see below)  and  trying
         an ordinary match again. There is some code that demonstrates how to do
         this in the pcredemo.c sample program.
           PCRE_NO_UTF8_CHECK
         When PCRE_UTF8 is set at compile time, the validity of the subject as a
-        UTF-8 string is automatically checked when pcre_exec() is  subsequently
+        UTF-8  string is automatically checked when pcre_exec() is subsequently
-        called.   The  value  of  startoffset is also checked to ensure that it
+        called.  The value of startoffset is also checked  to  ensure  that  it
-        points to the start of a UTF-8 character. If an invalid UTF-8  sequence
+        points  to the start of a UTF-8 character. If an invalid UTF-8 sequence
         of bytes is found, pcre_exec() returns the error PCRE_ERROR_BADUTF8. If
-        startoffset contains an  invalid  value,  PCRE_ERROR_BADUTF8_OFFSET  is
+        startoffset  contains  an  invalid  value, PCRE_ERROR_BADUTF8_OFFSET is
         returned.
-        If  you  already  know that your subject is valid, and you want to skip
+        If you already know that your subject is valid, and you  want  to  skip
-        these   checks   for   performance   reasons,   you   can    set    the
+        these    checks    for   performance   reasons,   you   can   set   the
-        PCRE_NO_UTF8_CHECK  option  when calling pcre_exec(). You might want to
+        PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might  want  to
-        do this for the second and subsequent calls to pcre_exec() if  you  are
+        do  this  for the second and subsequent calls to pcre_exec() if you are
-        making  repeated  calls  to  find  all  the matches in a single subject
+        making repeated calls to find all  the  matches  in  a  single  subject
-        string. However, you should be  sure  that  the  value  of  startoffset
+        string.  However,  you  should  be  sure  that the value of startoffset
-        points  to  the  start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is
+        points to the start of a UTF-8 character.  When  PCRE_NO_UTF8_CHECK  is
-        set, the effect of passing an invalid UTF-8 string as a subject,  or  a
+        set,  the  effect of passing an invalid UTF-8 string as a subject, or a
-        value  of startoffset that does not point to the start of a UTF-8 char-
+        value of startoffset that does not point to the start of a UTF-8  char-
         acter, is undefined. Your program may crash.
           PCRE_PARTIAL
-        This option turns on the  partial  matching  feature.  If  the  subject
+        This  option  turns  on  the  partial  matching feature. If the subject
-        string  fails to match the pattern, but at some point during the match-
+        string fails to match the pattern, but at some point during the  match-
-        ing process the end of the subject was reached (that  is,  the  subject
+        ing  process  the  end of the subject was reached (that is, the subject
-        partially  matches  the  pattern and the failure to match occurred only
+        partially matches the pattern and the failure to  match  occurred  only
-        because there were not enough subject characters), pcre_exec()  returns
+        because  there were not enough subject characters), pcre_exec() returns
-        PCRE_ERROR_PARTIAL  instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is
+        PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL  is
-        used, there are restrictions on what may appear in the  pattern.  These
+        used,  there  are restrictions on what may appear in the pattern. These
         are discussed in the pcrepartial documentation.
     The string to be matched by pcre_exec()
-        The  subject string is passed to pcre_exec() as a pointer in subject, a
+        The subject string is passed to pcre_exec() as a pointer in subject,  a
-        length in length, and a starting byte offset in startoffset.  In  UTF-8
+        length  in  length, and a starting byte offset in startoffset. In UTF-8
-        mode,  the  byte  offset  must point to the start of a UTF-8 character.
+        mode, the byte offset must point to the start  of  a  UTF-8  character.
-        Unlike the pattern string, the subject may contain binary  zero  bytes.
+        Unlike  the  pattern string, the subject may contain binary zero bytes.
-        When  the starting offset is zero, the search for a match starts at the
+        When the starting offset is zero, the search for a match starts at  the
         beginning of the subject, and this is by far the most common case.
-        A non-zero starting offset is useful when searching for  another  match
+        A  non-zero  starting offset is useful when searching for another match
-        in  the same subject by calling pcre_exec() again after a previous suc-
+        in the same subject by calling pcre_exec() again after a previous  suc-
-        cess.  Setting startoffset differs from just passing over  a  shortened
+        cess.   Setting  startoffset differs from just passing over a shortened
-        string  and  setting  PCRE_NOTBOL  in the case of a pattern that begins
+        string and setting PCRE_NOTBOL in the case of  a  pattern  that  begins
         with any kind of lookbehind. For example, consider the pattern
           \Biss\B
-        which finds occurrences of "iss" in the middle of  words.  (\B  matches
+        which  finds  occurrences  of "iss" in the middle of words. (\B matches
-        only  if  the  current position in the subject is not a word boundary.)
+        only if the current position in the subject is not  a  word  boundary.)
-        When applied to the string "Mississipi" the first call  to  pcre_exec()
+        When  applied  to the string "Mississipi" the first call to pcre_exec()
-        finds  the  first  occurrence. If pcre_exec() is called again with just
+        finds the first occurrence. If pcre_exec() is called  again  with  just
-        the remainder of the subject,  namely  "issipi",  it  does  not  match,
+        the  remainder  of  the  subject,  namely  "issipi", it does not match,
         because \B is always false at the start of the subject, which is deemed
-        to be a word boundary. However, if pcre_exec()  is  passed  the  entire
+        to  be  a  word  boundary. However, if pcre_exec() is passed the entire
         string again, but with startoffset set to 4, it finds the second occur-
-        rence of "iss" because it is able to look behind the starting point  to
+        rence  of "iss" because it is able to look behind the starting point to
         discover that it is preceded by a letter.
-        If  a  non-zero starting offset is passed when the pattern is anchored,
+        If a non-zero starting offset is passed when the pattern  is  anchored,
         one attempt to match at the given offset is made. This can only succeed
-        if  the  pattern  does  not require the match to be at the start of the
+        if the pattern does not require the match to be at  the  start  of  the
         subject.
     How pcre_exec() returns captured substrings
-        In general, a pattern matches a certain portion of the subject, and  in
+        In  general, a pattern matches a certain portion of the subject, and in
-        addition,  further  substrings  from  the  subject may be picked out by
+        addition, further substrings from the subject  may  be  picked  out  by
-        parts of the pattern. Following the usage  in  Jeffrey  Friedl's  book,
+        parts  of  the  pattern.  Following the usage in Jeffrey Friedl's book,
-        this  is  called "capturing" in what follows, and the phrase "capturing
+        this is called "capturing" in what follows, and the  phrase  "capturing
-        subpattern" is used for a fragment of a pattern that picks out  a  sub-
+        subpattern"  is  used for a fragment of a pattern that picks out a sub-
-        string.  PCRE  supports several other kinds of parenthesized subpattern
+        string. PCRE supports several other kinds of  parenthesized  subpattern
         that do not cause substrings to be captured.
-        Captured substrings are returned to the caller via a vector of  integer
+        Captured  substrings are returned to the caller via a vector of integer
-        offsets  whose  address is passed in ovector. The number of elements in
+        offsets whose address is passed in ovector. The number of  elements  in
-        the vector is passed in ovecsize, which must be a non-negative  number.
+        the  vector is passed in ovecsize, which must be a non-negative number.
         Note: this argument is NOT the size of ovector in bytes.
-        The  first  two-thirds of the vector is used to pass back captured sub-
+        The first two-thirds of the vector is used to pass back  captured  sub-
-        strings, each substring using a pair of integers. The  remaining  third
+        strings,  each  substring using a pair of integers. The remaining third
-        of  the  vector is used as workspace by pcre_exec() while matching cap-
+        of the vector is used as workspace by pcre_exec() while  matching  cap-
-        turing subpatterns, and is not available for passing back  information.
+        turing  subpatterns, and is not available for passing back information.
-        The  length passed in ovecsize should always be a multiple of three. If
+        The length passed in ovecsize should always be a multiple of three.  If
         it is not, it is rounded down.
-        When a match is successful, information about  captured  substrings  is
+        When  a  match  is successful, information about captured substrings is
-        returned  in  pairs  of integers, starting at the beginning of ovector,
+        returned in pairs of integers, starting at the  beginning  of  ovector,
-        and continuing up to two-thirds of its length at the  most.  The  first
+        and  continuing  up  to two-thirds of its length at the most. The first
         element of a pair is set to the offset of the first character in a sub-
-        string, and the second is set to the  offset  of  the  first  character
+        string,  and  the  second  is  set to the offset of the first character
-        after  the  end  of  a  substring. The first pair, ovector[0] and ovec-
+        after the end of a substring. The  first  pair,  ovector[0]  and  ovec-
-        tor[1], identify the portion of  the  subject  string  matched  by  the
+        tor[1],  identify  the  portion  of  the  subject string matched by the
-        entire  pattern.  The next pair is used for the first capturing subpat-
+        entire pattern. The next pair is used for the first  capturing  subpat-
         tern, and so on. The value returned by pcre_exec() is one more than the
         highest numbered pair that has been set. For example, if two substrings
-        have been captured, the returned value is 3. If there are no  capturing
+        have  been captured, the returned value is 3. If there are no capturing
-        subpatterns,  the return value from a successful match is 1, indicating
+        subpatterns, the return value from a successful match is 1,  indicating
         that just the first pair of offsets has been set.
         If a capturing subpattern is matched repeatedly, it is the last portion
         of the string that it matched that is returned.
-        If  the vector is too small to hold all the captured substring offsets,
+        If the vector is too small to hold all the captured substring  offsets,
         it is used as far as possible (up to two-thirds of its length), and the
-        function  returns a value of zero. In particular, if the substring off-
+        function returns a value of zero. In particular, if the substring  off-
         sets are not of interest, pcre_exec() may be called with ovector passed
-        as  NULL  and  ovecsize  as zero. However, if the pattern contains back
+        as NULL and ovecsize as zero. However, if  the  pattern  contains  back
-        references and the ovector is not big enough to  remember  the  related
+        references  and  the  ovector is not big enough to remember the related
-        substrings,  PCRE has to get additional memory for use during matching.
+        substrings, PCRE has to get additional memory for use during  matching.
         Thus it is usually advisable to supply an ovector.
-        The pcre_info() function can be used to find  out  how  many  capturing
+        The  pcre_info()  function  can  be used to find out how many capturing
-        subpatterns  there  are  in  a  compiled pattern. The smallest size for
+        subpatterns there are in a compiled  pattern.  The  smallest  size  for
-        ovector that will allow for n captured substrings, in addition  to  the
+        ovector  that  will allow for n captured substrings, in addition to the
         offsets of the substring matched by the whole pattern, is (n+1)*3.
-        It  is  possible for capturing subpattern number n+1 to match some part
+        It is possible for capturing subpattern number n+1 to match  some  part
         of the subject when subpattern n has not been used at all. For example,
-        if  the  string  "abc"  is  matched against the pattern (a|(z))(bc) the
+        if the string "abc" is matched  against  the  pattern  (a|(z))(bc)  the
         return from the function is 4, and subpatterns 1 and 3 are matched, but
- is  not.  When  this happens, both values in the offset pairs corre-
+is not. When this happens, both values in  the  offset  pairs  corre-
         sponding to unused subpatterns are set to -1.
-        Offset values that correspond to unused subpatterns at the end  of  the
+        Offset  values  that correspond to unused subpatterns at the end of the
-        expression  are  also  set  to  -1. For example, if the string "abc" is
+        expression are also set to -1. For example,  if  the  string  "abc"  is
-        matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are  not
+        matched  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not
-        matched.  The  return  from the function is 2, because the highest used
+        matched. The return from the function is 2, because  the  highest  used
         capturing subpattern number is 1. However, you can refer to the offsets
-        for  the  second  and third capturing subpatterns if you wish (assuming
+        for the second and third capturing subpatterns if  you  wish  (assuming
         the vector is large enough, of course).
-        Some convenience functions are provided  for  extracting  the  captured
+        Some  convenience  functions  are  provided for extracting the captured
         substrings as separate strings. These are described below.
     Error return values from pcre_exec()
-        If  pcre_exec()  fails, it returns a negative number. The following are
+        If pcre_exec() fails, it returns a negative number. The  following  are
         defined in the header file:
           PCRE_ERROR_NOMATCH        (-1)
-Line 1937 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1955 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_NULL           (-2)
-        Either code or subject was passed as NULL,  or  ovector  was  NULL  and
+        Either  code  or  subject  was  passed as NULL, or ovector was NULL and
         ovecsize was not zero.
           PCRE_ERROR_BADOPTION      (-3)
-Line 1946 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1964 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_BADMAGIC       (-4)
-        PCRE  stores a 4-byte "magic number" at the start of the compiled code,
+        PCRE stores a 4-byte "magic number" at the start of the compiled  code,
         to catch the case when it is passed a junk pointer and to detect when a
         pattern that was compiled in an environment of one endianness is run in
-        an environment with the other endianness. This is the error  that  PCRE
+        an  environment  with the other endianness. This is the error that PCRE
         gives when the magic number is not present.
           PCRE_ERROR_UNKNOWN_OPCODE (-5)
         While running the pattern match, an unknown item was encountered in the
-        compiled pattern. This error could be caused by a bug  in  PCRE  or  by
+        compiled  pattern.  This  error  could be caused by a bug in PCRE or by
         overwriting of the compiled pattern.
           PCRE_ERROR_NOMEMORY       (-6)
-        If  a  pattern contains back references, but the ovector that is passed
+        If a pattern contains back references, but the ovector that  is  passed
         to pcre_exec() is not big enough to remember the referenced substrings,
-        PCRE  gets  a  block of memory at the start of matching to use for this
+        PCRE gets a block of memory at the start of matching to  use  for  this
-        purpose. If the call via pcre_malloc() fails, this error is given.  The
+        purpose.  If the call via pcre_malloc() fails, this error is given. The
         memory is automatically freed at the end of matching.
           PCRE_ERROR_NOSUBSTRING    (-7)
-        This  error is used by the pcre_copy_substring(), pcre_get_substring(),
+        This error is used by the pcre_copy_substring(),  pcre_get_substring(),
         and  pcre_get_substring_list()  functions  (see  below).  It  is  never
         returned by pcre_exec().
           PCRE_ERROR_MATCHLIMIT     (-8)
-        The  backtracking  limit,  as  specified  by the match_limit field in a
+        The backtracking limit, as specified by  the  match_limit  field  in  a
-        pcre_extra structure (or defaulted) was reached.  See  the  description
+        pcre_extra  structure  (or  defaulted) was reached. See the description
         above.
           PCRE_ERROR_CALLOUT        (-9)
         This error is never generated by pcre_exec() itself. It is provided for
-        use by callout functions that want to yield a distinctive  error  code.
+        use  by  callout functions that want to yield a distinctive error code.
         See the pcrecallout documentation for details.
           PCRE_ERROR_BADUTF8        (-10)
-        A  string  that contains an invalid UTF-8 byte sequence was passed as a
+        A string that contains an invalid UTF-8 byte sequence was passed  as  a
         subject.
           PCRE_ERROR_BADUTF8_OFFSET (-11)
         The UTF-8 byte sequence that was passed as a subject was valid, but the
-        value  of startoffset did not point to the beginning of a UTF-8 charac-
+        value of startoffset did not point to the beginning of a UTF-8  charac-
         ter.
           PCRE_ERROR_PARTIAL        (-12)
-        The subject string did not match, but it did match partially.  See  the
+        The  subject  string did not match, but it did match partially. See the
         pcrepartial documentation for details of partial matching.
           PCRE_ERROR_BADPARTIAL     (-13)
-        The  PCRE_PARTIAL  option  was  used with a compiled pattern containing
+        The PCRE_PARTIAL option was used with  a  compiled  pattern  containing
-        items that are not supported for partial matching. See the  pcrepartial
+        items  that are not supported for partial matching. See the pcrepartial
         documentation for details of partial matching.
           PCRE_ERROR_INTERNAL       (-14)
-        An  unexpected  internal error has occurred. This error could be caused
+        An unexpected internal error has occurred. This error could  be  caused
         by a bug in PCRE or by overwriting of the compiled pattern.
           PCRE_ERROR_BADCOUNT       (-15)
-        This error is given if the value of the ovecsize argument is  negative.
+        This  error is given if the value of the ovecsize argument is negative.
           PCRE_ERROR_RECURSIONLIMIT (-21)
         The internal recursion limit, as specified by the match_limit_recursion
-        field in a pcre_extra structure (or defaulted)  was  reached.  See  the
+        field  in  a  pcre_extra  structure (or defaulted) was reached. See the
         description above.
           PCRE_ERROR_NULLWSLIMIT    (-22)
-        When  a  group  that  can  match an empty substring is repeated with an
+        When a group that can match an empty  substring  is  repeated  with  an
-        unbounded upper limit, the subject position at the start of  the  group
+        unbounded  upper  limit, the subject position at the start of the group
         must be remembered, so that a test for an empty string can be made when
-        the end of the group is reached. Some workspace is required  for  this;
+        the  end  of the group is reached. Some workspace is required for this;
         if it runs out, this error is given.
           PCRE_ERROR_BADNEWLINE     (-23)
-Line 2049 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
+Line 2067 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
         int pcre_get_substring_list(const char *subject,
              int *ovector, int stringcount, const char ***listptr);
-        Captured  substrings  can  be  accessed  directly  by using the offsets
+        Captured substrings can be  accessed  directly  by  using  the  offsets
-        returned by pcre_exec() in  ovector.  For  convenience,  the  functions
+        returned  by  pcre_exec()  in  ovector.  For convenience, the functions
         pcre_copy_substring(),    pcre_get_substring(),    and    pcre_get_sub-
-        string_list() are provided for extracting captured substrings  as  new,
+        string_list()  are  provided for extracting captured substrings as new,
-        separate,  zero-terminated strings. These functions identify substrings
+        separate, zero-terminated strings. These functions identify  substrings
-        by number. The next section describes functions  for  extracting  named
+        by  number.  The  next section describes functions for extracting named
         substrings.
-        A  substring that contains a binary zero is correctly extracted and has
+        A substring that contains a binary zero is correctly extracted and  has
-        a further zero added on the end, but the result is not, of course, a  C
+        a  further zero added on the end, but the result is not, of course, a C
-        string.   However,  you  can  process such a string by referring to the
+        string.  However, you can process such a string  by  referring  to  the
-        length that is  returned  by  pcre_copy_substring()  and  pcre_get_sub-
+        length  that  is  returned  by  pcre_copy_substring() and pcre_get_sub-
         string().  Unfortunately, the interface to pcre_get_substring_list() is
-        not adequate for handling strings containing binary zeros, because  the
+        not  adequate for handling strings containing binary zeros, because the
         end of the final string is not independently indicated.
-        The  first  three  arguments  are the same for all three of these func-
+        The first three arguments are the same for all  three  of  these  func-
-        tions: subject is the subject string that has  just  been  successfully
+        tions:  subject  is  the subject string that has just been successfully
         matched, ovector is a pointer to the vector of integer offsets that was
         passed to pcre_exec(), and stringcount is the number of substrings that
-        were  captured  by  the match, including the substring that matched the
+        were captured by the match, including the substring  that  matched  the
         entire regular expression. This is the value returned by pcre_exec() if
-        it  is greater than zero. If pcre_exec() returned zero, indicating that
+        it is greater than zero. If pcre_exec() returned zero, indicating  that
-        it ran out of space in ovector, the value passed as stringcount  should
+        it  ran out of space in ovector, the value passed as stringcount should
         be the number of elements in the vector divided by three.
-        The  functions pcre_copy_substring() and pcre_get_substring() extract a
+        The functions pcre_copy_substring() and pcre_get_substring() extract  a
-        single substring, whose number is given as  stringnumber.  A  value  of
+        single  substring,  whose  number  is given as stringnumber. A value of
-        zero  extracts  the  substring that matched the entire pattern, whereas
+        zero extracts the substring that matched the  entire  pattern,  whereas
-        higher values  extract  the  captured  substrings.  For  pcre_copy_sub-
+        higher  values  extract  the  captured  substrings.  For pcre_copy_sub-
-        string(),  the  string  is  placed  in buffer, whose length is given by
+        string(), the string is placed in buffer,  whose  length  is  given  by
-        buffersize, while for pcre_get_substring() a new  block  of  memory  is
+        buffersize,  while  for  pcre_get_substring()  a new block of memory is
-        obtained  via  pcre_malloc,  and its address is returned via stringptr.
+        obtained via pcre_malloc, and its address is  returned  via  stringptr.
-        The yield of the function is the length of the  string,  not  including
+        The  yield  of  the function is the length of the string, not including
         the terminating zero, or one of these error codes:
           PCRE_ERROR_NOMEMORY       (-6)
-        The  buffer  was too small for pcre_copy_substring(), or the attempt to
+        The buffer was too small for pcre_copy_substring(), or the  attempt  to
         get memory failed for pcre_get_substring().
           PCRE_ERROR_NOSUBSTRING    (-7)
         There is no substring whose number is stringnumber.
-        The pcre_get_substring_list()  function  extracts  all  available  sub-
+        The  pcre_get_substring_list()  function  extracts  all  available sub-
-        strings  and  builds  a list of pointers to them. All this is done in a
+        strings and builds a list of pointers to them. All this is  done  in  a
         single block of memory that is obtained via pcre_malloc. The address of
-        the  memory  block  is returned via listptr, which is also the start of
+        the memory block is returned via listptr, which is also  the  start  of
-        the list of string pointers. The end of the list is marked  by  a  NULL
+        the  list  of  string pointers. The end of the list is marked by a NULL
-        pointer.  The  yield  of  the function is zero if all went well, or the
+        pointer. The yield of the function is zero if all  went  well,  or  the
         error code
           PCRE_ERROR_NOMEMORY       (-6)
         if the attempt to get the memory block failed.
-        When any of these functions encounter a substring that is unset,  which
+        When  any of these functions encounter a substring that is unset, which
-        can  happen  when  capturing subpattern number n+1 matches some part of
+        can happen when capturing subpattern number n+1 matches  some  part  of
-        the subject, but subpattern n has not been used at all, they return  an
+        the  subject, but subpattern n has not been used at all, they return an
         empty string. This can be distinguished from a genuine zero-length sub-
-        string by inspecting the appropriate offset in ovector, which is  nega-
+        string  by inspecting the appropriate offset in ovector, which is nega-
         tive for unset substrings.
-        The  two convenience functions pcre_free_substring() and pcre_free_sub-
+        The two convenience functions pcre_free_substring() and  pcre_free_sub-
-        string_list() can be used to free the memory  returned  by  a  previous
+        string_list()  can  be  used  to free the memory returned by a previous
         call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-
-        tively. They do nothing more than  call  the  function  pointed  to  by
+        tively.  They  do  nothing  more  than  call the function pointed to by
-        pcre_free,  which  of course could be called directly from a C program.
+        pcre_free, which of course could be called directly from a  C  program.
-        However, PCRE is used in some situations where it is linked via a  spe-
+        However,  PCRE is used in some situations where it is linked via a spe-
-        cial   interface  to  another  programming  language  that  cannot  use
+        cial  interface  to  another  programming  language  that  cannot   use
-        pcre_free directly; it is for these cases that the functions  are  pro-
+        pcre_free  directly;  it is for these cases that the functions are pro-
         vided.
-Line 2139 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 2157 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
              int stringcount, const char *stringname,
              const char **stringptr);
-        To  extract a substring by name, you first have to find associated num-
+        To extract a substring by name, you first have to find associated  num-
         ber.  For example, for this pattern
           (a+)b(?<xxx>\d+)...
-Line 2148 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 2166 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
         be unique (PCRE_DUPNAMES was not set), you can find the number from the
         name by calling pcre_get_stringnumber(). The first argument is the com-
         piled pattern, and the second is the name. The yield of the function is
-        the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if  there  is  no
+        the  subpattern  number,  or PCRE_ERROR_NOSUBSTRING (-7) if there is no
         subpattern of that name.
         Given the number, you can extract the substring directly, or use one of
         the functions described in the previous section. For convenience, there
         are also two functions that do the whole job.
-        Most    of    the    arguments   of   pcre_copy_named_substring()   and
+        Most   of   the   arguments    of    pcre_copy_named_substring()    and
-        pcre_get_named_substring() are the same  as  those  for  the  similarly
+        pcre_get_named_substring()  are  the  same  as  those for the similarly
-        named  functions  that extract by number. As these are described in the
+        named functions that extract by number. As these are described  in  the
-        previous section, they are not re-described here. There  are  just  two
+        previous  section,  they  are not re-described here. There are just two
         differences:
-        First,  instead  of a substring number, a substring name is given. Sec-
+        First, instead of a substring number, a substring name is  given.  Sec-
         ond, there is an extra argument, given at the start, which is a pointer
-        to  the compiled pattern. This is needed in order to gain access to the
+        to the compiled pattern. This is needed in order to gain access to  the
         name-to-number translation table.
-        These functions call pcre_get_stringnumber(), and if it succeeds,  they
+        These  functions call pcre_get_stringnumber(), and if it succeeds, they
-        then  call  pcre_copy_substring() or pcre_get_substring(), as appropri-
+        then call pcre_copy_substring() or pcre_get_substring(),  as  appropri-
-        ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate  names,  the
+        ate.  NOTE:  If PCRE_DUPNAMES is set and there are duplicate names, the
         behaviour may not be what you want (see the next section).
-Line 2177 
 DUPLICATE SUBPATTERN NAMES
+Line 2195 
 DUPLICATE SUBPATTERN NAMES
         int pcre_get_stringtable_entries(const pcre *code,
              const char *name, char **first, char **last);
-        When  a  pattern  is  compiled with the PCRE_DUPNAMES option, names for
+        When a pattern is compiled with the  PCRE_DUPNAMES  option,  names  for
-        subpatterns are not required to  be  unique.  Normally,  patterns  with
+        subpatterns  are  not  required  to  be unique. Normally, patterns with
-        duplicate  names  are such that in any one match, only one of the named
+        duplicate names are such that in any one match, only one of  the  named
-        subpatterns participates. An example is shown in the pcrepattern  docu-
+        subpatterns  participates. An example is shown in the pcrepattern docu-
         mentation. When duplicates are present, pcre_copy_named_substring() and
-        pcre_get_named_substring() return the first substring corresponding  to
+        pcre_get_named_substring()  return the first substring corresponding to
-        the  given  name  that  is  set.  If  none  are set, an empty string is
+        the given name that is set.  If  none  are  set,  an  empty  string  is
         returned.  The pcre_get_stringnumber() function returns one of the num-
-        bers  that are associated with the name, but it is not defined which it
+        bers that are associated with the name, but it is not defined which  it
         is.
-        If you want to get full details of all captured substrings for a  given
+        If  you want to get full details of all captured substrings for a given
-        name,  you  must  use  the pcre_get_stringtable_entries() function. The
+        name, you must use  the  pcre_get_stringtable_entries()  function.  The
         first argument is the compiled pattern, and the second is the name. The
-        third  and  fourth  are  pointers to variables which are updated by the
+        third and fourth are pointers to variables which  are  updated  by  the
         function. After it has run, they point to the first and last entries in
-        the  name-to-number  table  for  the  given  name.  The function itself
+        the name-to-number table  for  the  given  name.  The  function  itself
-        returns the length of each entry,  or  PCRE_ERROR_NOSUBSTRING  (-7)  if
+        returns  the  length  of  each entry, or PCRE_ERROR_NOSUBSTRING (-7) if
-        there  are none. The format of the table is described above in the sec-
+        there are none. The format of the table is described above in the  sec-
-        tion entitled Information about a  pattern.   Given  all  the  relevant
+        tion  entitled  Information  about  a  pattern.  Given all the relevant
-        entries  for the name, you can extract each of their numbers, and hence
+        entries for the name, you can extract each of their numbers, and  hence
         the captured data, if any.
  FINDING ALL POSSIBLE MATCHES
-        The traditional matching function uses a  similar  algorithm  to  Perl,
+        The  traditional  matching  function  uses a similar algorithm to Perl,
         which stops when it finds the first match, starting at a given point in
-        the subject. If you want to find all possible matches, or  the  longest
+        the  subject.  If you want to find all possible matches, or the longest
-        possible  match,  consider using the alternative matching function (see
+        possible match, consider using the alternative matching  function  (see
-        below) instead. If you cannot use the alternative function,  but  still
+        below)  instead.  If you cannot use the alternative function, but still
-        need  to  find all possible matches, you can kludge it up by making use
+        need to find all possible matches, you can kludge it up by  making  use
         of the callout facility, which is described in the pcrecallout documen-
         tation.
         What you have to do is to insert a callout right at the end of the pat-
-        tern.  When your callout function is called, extract and save the  cur-
+        tern.   When your callout function is called, extract and save the cur-
-        rent  matched  substring.  Then  return  1, which forces pcre_exec() to
+        rent matched substring. Then return  1,  which  forces  pcre_exec()  to
-        backtrack and try other alternatives. Ultimately, when it runs  out  of
+        backtrack  and  try other alternatives. Ultimately, when it runs out of
         matches, pcre_exec() will yield PCRE_ERROR_NOMATCH.
-Line 2226 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2244 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
              int options, int *ovector, int ovecsize,
              int *workspace, int wscount);
-        The  function  pcre_dfa_exec()  is  called  to  match  a subject string
+        The function pcre_dfa_exec()  is  called  to  match  a  subject  string
-        against a compiled pattern, using a matching algorithm that  scans  the
+        against  a  compiled pattern, using a matching algorithm that scans the
-        subject  string  just  once, and does not backtrack. This has different
+        subject string just once, and does not backtrack.  This  has  different
-        characteristics to the normal algorithm, and  is  not  compatible  with
+        characteristics  to  the  normal  algorithm, and is not compatible with
-        Perl.  Some  of the features of PCRE patterns are not supported. Never-
+        Perl. Some of the features of PCRE patterns are not  supported.  Never-
-        theless, there are times when this kind of matching can be useful.  For
+        theless,  there are times when this kind of matching can be useful. For
         a discussion of the two matching algorithms, see the pcrematching docu-
         mentation.
-        The arguments for the pcre_dfa_exec() function  are  the  same  as  for
+        The  arguments  for  the  pcre_dfa_exec()  function are the same as for
         pcre_exec(), plus two extras. The ovector argument is used in a differ-
-        ent way, and this is described below. The other  common  arguments  are
+        ent  way,  and  this is described below. The other common arguments are
-        used  in  the  same way as for pcre_exec(), so their description is not
+        used in the same way as for pcre_exec(), so their  description  is  not
         repeated here.
-        The two additional arguments provide workspace for  the  function.  The
+        The  two  additional  arguments provide workspace for the function. The
-        workspace  vector  should  contain at least 20 elements. It is used for
+        workspace vector should contain at least 20 elements. It  is  used  for
         keeping  track  of  multiple  paths  through  the  pattern  tree.  More
-        workspace  will  be  needed for patterns and subjects where there are a
+        workspace will be needed for patterns and subjects where  there  are  a
         lot of potential matches.
         Here is an example of a simple call to pcre_dfa_exec():
-Line 2266 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2284 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
     Option bits for pcre_dfa_exec()
-        The unused bits of the options argument  for  pcre_dfa_exec()  must  be
+        The  unused  bits  of  the options argument for pcre_dfa_exec() must be
-        zero.  The  only  bits  that  may  be  set are PCRE_ANCHORED, PCRE_NEW-
+        zero. The only bits  that  may  be  set  are  PCRE_ANCHORED,  PCRE_NEW-
-        LINE_xxx, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,  PCRE_NO_UTF8_CHECK,
+        LINE_xxx,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK,
         PCRE_PARTIAL, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last
         three of these are the same as for pcre_exec(), so their description is
         not repeated here.
           PCRE_PARTIAL
-        This  has  the  same general effect as it does for pcre_exec(), but the
+        This has the same general effect as it does for  pcre_exec(),  but  the
-        details  are  slightly  different.  When  PCRE_PARTIAL   is   set   for
+        details   are   slightly   different.  When  PCRE_PARTIAL  is  set  for
-        pcre_dfa_exec(),  the  return code PCRE_ERROR_NOMATCH is converted into
+        pcre_dfa_exec(), the return code PCRE_ERROR_NOMATCH is  converted  into
-        PCRE_ERROR_PARTIAL if the end of the subject  is  reached,  there  have
+        PCRE_ERROR_PARTIAL  if  the  end  of the subject is reached, there have
         been no complete matches, but there is still at least one matching pos-
-        sibility. The portion of the string that provided the partial match  is
+        sibility.  The portion of the string that provided the partial match is
         set as the first matching string.
           PCRE_DFA_SHORTEST
-        Setting  the  PCRE_DFA_SHORTEST option causes the matching algorithm to
+        Setting the PCRE_DFA_SHORTEST option causes the matching  algorithm  to
         stop as soon as it has found one match. Because of the way the alterna-
-        tive  algorithm  works, this is necessarily the shortest possible match
+        tive algorithm works, this is necessarily the shortest  possible  match
         at the first possible matching point in the subject string.
           PCRE_DFA_RESTART
-        When pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option,  and
+        When  pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option, and
-        returns  a  partial  match, it is possible to call it again, with addi-
+        returns a partial match, it is possible to call it  again,  with  addi-
-        tional subject characters, and have it continue with  the  same  match.
+        tional  subject  characters,  and have it continue with the same match.
-        The  PCRE_DFA_RESTART  option requests this action; when it is set, the
+        The PCRE_DFA_RESTART option requests this action; when it is  set,  the
-        workspace and wscount options must reference the same vector as  before
+        workspace  and wscount options must reference the same vector as before
-        because  data  about  the  match so far is left in them after a partial
+        because data about the match so far is left in  them  after  a  partial
-        match. There is more discussion of this  facility  in  the  pcrepartial
+        match.  There  is  more  discussion of this facility in the pcrepartial
         documentation.
     Successful returns from pcre_dfa_exec()
-        When  pcre_dfa_exec()  succeeds, it may have matched more than one sub-
+        When pcre_dfa_exec() succeeds, it may have matched more than  one  sub-
         string in the subject. Note, however, that all the matches from one run
-        of  the  function  start  at the same point in the subject. The shorter
+        of the function start at the same point in  the  subject.  The  shorter
-        matches are all initial substrings of the longer matches. For  example,
+        matches  are all initial substrings of the longer matches. For example,
         if the pattern
           <.*>
-Line 2321 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2339 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
           <something> <something else>
           <something> <something else> <something further>
-        On  success,  the  yield of the function is a number greater than zero,
+        On success, the yield of the function is a number  greater  than  zero,
-        which is the number of matched substrings.  The  substrings  themselves
+        which  is  the  number of matched substrings. The substrings themselves
-        are  returned  in  ovector. Each string uses two elements; the first is
+        are returned in ovector. Each string uses two elements;  the  first  is
-        the offset to the start, and the second is the offset to  the  end.  In
+        the  offset  to  the start, and the second is the offset to the end. In
-        fact,  all  the  strings  have the same start offset. (Space could have
+        fact, all the strings have the same start  offset.  (Space  could  have
-        been saved by giving this only once, but it was decided to retain  some
+        been  saved by giving this only once, but it was decided to retain some
-        compatibility  with  the  way pcre_exec() returns data, even though the
+        compatibility with the way pcre_exec() returns data,  even  though  the
         meaning of the strings is different.)
         The strings are returned in reverse order of length; that is, the long-
-        est  matching  string is given first. If there were too many matches to
+        est matching string is given first. If there were too many  matches  to
-        fit into ovector, the yield of the function is zero, and the vector  is
+        fit  into ovector, the yield of the function is zero, and the vector is
         filled with the longest matches.
     Error returns from pcre_dfa_exec()
-        The  pcre_dfa_exec()  function returns a negative number when it fails.
+        The pcre_dfa_exec() function returns a negative number when  it  fails.
-        Many of the errors are the same  as  for  pcre_exec(),  and  these  are
+        Many  of  the  errors  are  the  same as for pcre_exec(), and these are
-        described  above.   There are in addition the following errors that are
+        described above.  There are in addition the following errors  that  are
         specific to pcre_dfa_exec():
           PCRE_ERROR_DFA_UITEM      (-16)
-        This return is given if pcre_dfa_exec() encounters an item in the  pat-
+        This  return is given if pcre_dfa_exec() encounters an item in the pat-
-        tern  that  it  does not support, for instance, the use of \C or a back
+        tern that it does not support, for instance, the use of \C  or  a  back
         reference.
           PCRE_ERROR_DFA_UCOND      (-17)
-        This return is given if pcre_dfa_exec()  encounters  a  condition  item
+        This  return  is  given  if pcre_dfa_exec() encounters a condition item
-        that  uses  a back reference for the condition, or a test for recursion
+        that uses a back reference for the condition, or a test  for  recursion
         in a specific group. These are not supported.
           PCRE_ERROR_DFA_UMLIMIT    (-18)
-        This return is given if pcre_dfa_exec() is called with an  extra  block
+        This  return  is given if pcre_dfa_exec() is called with an extra block
         that contains a setting of the match_limit field. This is not supported
         (it is meaningless).
           PCRE_ERROR_DFA_WSSIZE     (-19)
-        This return is given if  pcre_dfa_exec()  runs  out  of  space  in  the
+        This  return  is  given  if  pcre_dfa_exec()  runs  out of space in the
         workspace vector.
           PCRE_ERROR_DFA_RECURSE    (-20)
-        When  a  recursive subpattern is processed, the matching function calls
+        When a recursive subpattern is processed, the matching  function  calls
-        itself recursively, using private vectors for  ovector  and  workspace.
+        itself  recursively,  using  private vectors for ovector and workspace.
-        This  error  is  given  if  the output vector is not large enough. This
+        This error is given if the output vector  is  not  large  enough.  This
         should be extremely rare, as a vector of size 1000 is used.
  SEE ALSO
-        pcrebuild(3), pcrecallout(3), pcrecpp(3)(3), pcrematching(3),  pcrepar-
+        pcrebuild(3),  pcrecallout(3), pcrecpp(3)(3), pcrematching(3), pcrepar-
-        tial(3),  pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3).
+        tial(3), pcreposix(3), pcreprecompile(3), pcresample(3),  pcrestack(3).
  AUTHOR
-Line 2388 
 AUTHOR
+Line 2406 
 AUTHOR
  REVISION
-        Last updated: 24 April 2007
+        Last updated: 04 June 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2491 
 THE CALLOUT INTERFACE
+Line 2509 
 THE CALLOUT INTERFACE
         The subject and subject_length fields contain copies of the values that
         were passed to pcre_exec().
-        The start_match field contains the offset within the subject  at  which
+        The start_match field normally contains the offset within  the  subject
-        the  current match attempt started. If the pattern is not anchored, the
+        at  which  the  current  match  attempt started. However, if the escape
-        callout function may be called several times from the same point in the
+        sequence \K has been encountered, this value is changed to reflect  the
-        pattern for different starting points in the subject.
+        modified  starting  point.  If the pattern is not anchored, the callout
+        function may be called several times from the same point in the pattern
+        for different starting points in the subject.
         The  current_position  field  contains the offset within the subject of
         the current match pointer.
-Line 2557 
 AUTHOR
+Line 2577 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 29 May 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2718 
 PCRE REGULAR EXPRESSION DETAILS
+Line 2738 
 PCRE REGULAR EXPRESSION DETAILS
         ported  by  PCRE when its main matching function, pcre_exec(), is used.
         From  release  6.0,   PCRE   offers   a   second   matching   function,
         pcre_dfa_exec(),  which matches using a different algorithm that is not
-        Perl-compatible. The advantages and disadvantages  of  the  alternative
+        Perl-compatible. Some of the features discussed below are not available
-        function, and how it differs from the normal function, are discussed in
+        when  pcre_dfa_exec()  is used. The advantages and disadvantages of the
-        the pcrematching page.
+        alternative function, and how it differs from the normal function,  are
+        discussed in the pcrematching page.
  CHARACTERS AND METACHARACTERS
-        A regular expression is a pattern that is  matched  against  a  subject
+        A  regular  expression  is  a pattern that is matched against a subject
-        string  from  left  to right. Most characters stand for themselves in a
+        string from left to right. Most characters stand for  themselves  in  a
-        pattern, and match the corresponding characters in the  subject.  As  a
+        pattern,  and  match  the corresponding characters in the subject. As a
         trivial example, the pattern
           The quick brown fox
         matches a portion of a subject string that is identical to itself. When
-        caseless matching is specified (the PCRE_CASELESS option), letters  are
+        caseless  matching is specified (the PCRE_CASELESS option), letters are
-        matched  independently  of case. In UTF-8 mode, PCRE always understands
+        matched independently of case. In UTF-8 mode, PCRE  always  understands
-        the concept of case for characters whose values are less than  128,  so
+        the  concept  of case for characters whose values are less than 128, so
-        caseless  matching  is always possible. For characters with higher val-
+        caseless matching is always possible. For characters with  higher  val-
-        ues, the concept of case is supported if PCRE is compiled with  Unicode
+        ues,  the concept of case is supported if PCRE is compiled with Unicode
-        property  support,  but  not  otherwise.   If  you want to use caseless
+        property support, but not otherwise.   If  you  want  to  use  caseless
-        matching for characters 128 and above, you must  ensure  that  PCRE  is
+        matching  for  characters  128  and above, you must ensure that PCRE is
         compiled with Unicode property support as well as with UTF-8 support.
-        The  power  of  regular  expressions  comes from the ability to include
+        The power of regular expressions comes  from  the  ability  to  include
-        alternatives and repetitions in the pattern. These are encoded  in  the
+        alternatives  and  repetitions in the pattern. These are encoded in the
         pattern by the use of metacharacters, which do not stand for themselves
         but instead are interpreted in some special way.
-        There are two different sets of metacharacters: those that  are  recog-
+        There  are  two different sets of metacharacters: those that are recog-
-        nized  anywhere in the pattern except within square brackets, and those
+        nized anywhere in the pattern except within square brackets, and  those
-        that are recognized within square brackets.  Outside  square  brackets,
+        that  are  recognized  within square brackets. Outside square brackets,
         the metacharacters are as follows:
           \      general escape character with several uses
-Line 2768 
 CHARACTERS AND METACHARACTERS
+Line 2789 
 CHARACTERS AND METACHARACTERS
                  also "possessive quantifier"
           {      start min/max quantifier
-        Part  of  a  pattern  that is in square brackets is called a "character
+        Part of a pattern that is in square brackets  is  called  a  "character
         class". In a character class the only metacharacters are:
           \      general escape character
-Line 2778 
 CHARACTERS AND METACHARACTERS
+Line 2799 
 CHARACTERS AND METACHARACTERS
                    syntax)
           ]      terminates the character class
-        The following sections describe the use of each of the  metacharacters.
+        The  following sections describe the use of each of the metacharacters.
  BACKSLASH
         The backslash character has several uses. Firstly, if it is followed by
-        a non-alphanumeric character, it takes away any  special  meaning  that
+        a  non-alphanumeric  character,  it takes away any special meaning that
-        character  may  have.  This  use  of  backslash  as an escape character
+        character may have. This  use  of  backslash  as  an  escape  character
         applies both inside and outside character classes.
-        For example, if you want to match a * character, you write  \*  in  the
+        For  example,  if  you want to match a * character, you write \* in the
-        pattern.   This  escaping  action  applies whether or not the following
+        pattern.  This escaping action applies whether  or  not  the  following
-        character would otherwise be interpreted as a metacharacter, so  it  is
+        character  would  otherwise be interpreted as a metacharacter, so it is
-        always  safe  to  precede  a non-alphanumeric with backslash to specify
+        always safe to precede a non-alphanumeric  with  backslash  to  specify
-        that it stands for itself. In particular, if you want to match a  back-
+        that  it stands for itself. In particular, if you want to match a back-
         slash, you write \\.
-        If  a  pattern is compiled with the PCRE_EXTENDED option, whitespace in
+        If a pattern is compiled with the PCRE_EXTENDED option,  whitespace  in
-        the pattern (other than in a character class) and characters between  a
+        the  pattern (other than in a character class) and characters between a
         # outside a character class and the next newline are ignored. An escap-
-        ing backslash can be used to include a whitespace  or  #  character  as
+        ing  backslash  can  be  used to include a whitespace or # character as
         part of the pattern.
-        If  you  want  to remove the special meaning from a sequence of charac-
+        If you want to remove the special meaning from a  sequence  of  charac-
-        ters, you can do so by putting them between \Q and \E. This is  differ-
+        ters,  you can do so by putting them between \Q and \E. This is differ-
-        ent  from  Perl  in  that  $  and  @ are handled as literals in \Q...\E
+        ent from Perl in that $ and  @  are  handled  as  literals  in  \Q...\E
-        sequences in PCRE, whereas in Perl, $ and @ cause  variable  interpola-
+        sequences  in  PCRE, whereas in Perl, $ and @ cause variable interpola-
         tion. Note the following examples:
           Pattern            PCRE matches   Perl matches
-Line 2814 
 BACKSLASH
+Line 2835 
 BACKSLASH
           \Qabc\$xyz\E       abc\$xyz       abc\$xyz
           \Qabc\E\$\Qxyz\E   abc$xyz        abc$xyz
-        The  \Q...\E  sequence  is recognized both inside and outside character
+        The \Q...\E sequence is recognized both inside  and  outside  character
         classes.
     Non-printing characters
         A second use of backslash provides a way of encoding non-printing char-
-        acters  in patterns in a visible manner. There is no restriction on the
+        acters in patterns in a visible manner. There is no restriction on  the
-        appearance of non-printing characters, apart from the binary zero  that
+        appearance  of non-printing characters, apart from the binary zero that
-        terminates  a  pattern,  but  when  a pattern is being prepared by text
+        terminates a pattern, but when a pattern  is  being  prepared  by  text
-        editing, it is usually easier  to  use  one  of  the  following  escape
+        editing,  it  is  usually  easier  to  use  one of the following escape
         sequences than the binary character it represents:
           \a        alarm, that is, the BEL character (hex 07)
-Line 2837 
 BACKSLASH
+Line 2858 
 BACKSLASH
           \xhh      character with hex code hh
           \x{hhh..} character with hex code hhh..
-        The  precise  effect of \cx is as follows: if x is a lower case letter,
+        The precise effect of \cx is as follows: if x is a lower  case  letter,
-        it is converted to upper case. Then bit 6 of the character (hex 40)  is
+        it  is converted to upper case. Then bit 6 of the character (hex 40) is
-        inverted.   Thus  \cz becomes hex 1A, but \c{ becomes hex 3B, while \c;
+        inverted.  Thus \cz becomes hex 1A, but \c{ becomes hex 3B,  while  \c;
         becomes hex 7B.
-        After \x, from zero to two hexadecimal digits are read (letters can  be
+        After  \x, from zero to two hexadecimal digits are read (letters can be
-        in  upper  or  lower case). Any number of hexadecimal digits may appear
+        in upper or lower case). Any number of hexadecimal  digits  may  appear
-        between \x{ and }, but the value of the character  code  must  be  less
+        between  \x{  and  },  but the value of the character code must be less
         than 256 in non-UTF-8 mode, and less than 2**31 in UTF-8 mode (that is,
-        the maximum hexadecimal value is 7FFFFFFF). If  characters  other  than
+        the  maximum  hexadecimal  value is 7FFFFFFF). If characters other than
-        hexadecimal  digits  appear between \x{ and }, or if there is no termi-
+        hexadecimal digits appear between \x{ and }, or if there is  no  termi-
-        nating }, this form of escape is not recognized.  Instead, the  initial
+        nating  }, this form of escape is not recognized.  Instead, the initial
         \x will be interpreted as a basic hexadecimal escape, with no following
         digits, giving a character whose value is zero.
         Characters whose value is less than 256 can be defined by either of the
-        two  syntaxes  for  \x. There is no difference in the way they are han-
+        two syntaxes for \x. There is no difference in the way  they  are  han-
         dled. For example, \xdc is exactly the same as \x{dc}.
-        After \0 up to two further octal digits are read. If  there  are  fewer
+        After  \0  up  to two further octal digits are read. If there are fewer
-        than  two  digits,  just  those  that  are  present  are used. Thus the
+        than two digits, just  those  that  are  present  are  used.  Thus  the
         sequence \0\x\07 specifies two binary zeros followed by a BEL character
-        (code  value 7). Make sure you supply two digits after the initial zero
+        (code value 7). Make sure you supply two digits after the initial  zero
         if the pattern character that follows is itself an octal digit.
         The handling of a backslash followed by a digit other than 0 is compli-
         cated.  Outside a character class, PCRE reads it and any following dig-
-        its as a decimal number. If the number is less than  10,  or  if  there
+        its  as  a  decimal  number. If the number is less than 10, or if there
         have been at least that many previous capturing left parentheses in the
-        expression, the entire  sequence  is  taken  as  a  back  reference.  A
+        expression,  the  entire  sequence  is  taken  as  a  back reference. A
-        description  of how this works is given later, following the discussion
+        description of how this works is given later, following the  discussion
         of parenthesized subpatterns.
-        Inside a character class, or if the decimal number is  greater  than  9
+        Inside  a  character  class, or if the decimal number is greater than 9
-        and  there have not been that many capturing subpatterns, PCRE re-reads
+        and there have not been that many capturing subpatterns, PCRE  re-reads
         up to three octal digits following the backslash, and uses them to gen-
-        erate  a data character. Any subsequent digits stand for themselves. In
+        erate a data character. Any subsequent digits stand for themselves.  In
-        non-UTF-8 mode, the value of a character specified  in  octal  must  be
+        non-UTF-8  mode,  the  value  of a character specified in octal must be
-        less  than  \400.  In  UTF-8 mode, values up to \777 are permitted. For
+        less than \400. In UTF-8 mode, values up to  \777  are  permitted.  For
         example:
           \040   is another way of writing a space
-Line 2893 
 BACKSLASH
+Line 2914 
 BACKSLASH
           \81    is either a back reference, or a binary zero
                     followed by the two characters "8" and "1"
-        Note that octal values of 100 or greater must not be  introduced  by  a
+        Note  that  octal  values of 100 or greater must not be introduced by a
         leading zero, because no more than three octal digits are ever read.
         All the sequences that define a single character value can be used both
-        inside and outside character classes. In addition, inside  a  character
+        inside  and  outside character classes. In addition, inside a character
-        class,  the  sequence \b is interpreted as the backspace character (hex
+        class, the sequence \b is interpreted as the backspace  character  (hex
-), and the sequences \R and \X are interpreted as the characters  "R"
+),  and the sequences \R and \X are interpreted as the characters "R"
-        and  "X", respectively. Outside a character class, these sequences have
+        and "X", respectively. Outside a character class, these sequences  have
         different meanings (see below).
     Absolute and relative back references
-        The sequence \g followed by a positive or negative  number,  optionally
+        The  sequence  \g followed by a positive or negative number, optionally
-        enclosed  in  braces,  is  an absolute or relative back reference. Back
+        enclosed in braces, is an absolute or relative back reference. A  named
-        references are discussed later, following the discussion  of  parenthe-
+        back  reference can be coded as \g{name}. Back references are discussed
-        sized subpatterns.
+        later, following the discussion of parenthesized subpatterns.
     Generic character types
-Line 2923 
 BACKSLASH
+Line 2944 
 BACKSLASH
           \W     any "non-word" character
         Each pair of escape sequences partitions the complete set of characters
-        into  two disjoint sets. Any given character matches one, and only one,
+        into two disjoint sets. Any given character matches one, and only  one,
         of each pair.
         These character type sequences can appear both inside and outside char-
-        acter  classes.  They each match one character of the appropriate type.
+        acter classes. They each match one character of the  appropriate  type.
-        If the current matching point is at the end of the subject string,  all
+        If  the current matching point is at the end of the subject string, all
         of them fail, since there is no character to match.
-        For  compatibility  with Perl, \s does not match the VT character (code
+        For compatibility with Perl, \s does not match the VT  character  (code
-).  This makes it different from the the POSIX "space" class. The  \s
+).   This makes it different from the the POSIX "space" class. The \s
-        characters  are  HT (9), LF (10), FF (12), CR (13), and space (32). (If
+        characters are HT (9), LF (10), FF (12), CR (13), and space  (32).  (If
         "use locale;" is included in a Perl script, \s may match the VT charac-
         ter. In PCRE, it never does.)
         A "word" character is an underscore or any character less than 256 that
-        is a letter or digit. The definition of  letters  and  digits  is  con-
+        is  a  letter  or  digit.  The definition of letters and digits is con-
-        trolled  by PCRE's low-valued character tables, and may vary if locale-
+        trolled by PCRE's low-valued character tables, and may vary if  locale-
-        specific matching is taking place (see "Locale support" in the  pcreapi
+        specific  matching is taking place (see "Locale support" in the pcreapi
-        page).  For  example,  in  a French locale such as "fr_FR" in Unix-like
+        page). For example, in a French locale such  as  "fr_FR"  in  Unix-like
-        systems, or "french" in Windows, some character codes greater than  128
+        systems,  or "french" in Windows, some character codes greater than 128
         are used for accented letters, and these are matched by \w.
-        In  UTF-8 mode, characters with values greater than 128 never match \d,
+        In UTF-8 mode, characters with values greater than 128 never match  \d,
         \s, or \w, and always match \D, \S, and \W. This is true even when Uni-
-        code  character  property support is available. The use of locales with
+        code character property support is available. The use of  locales  with
         Unicode is discouraged.
     Newline sequences
-        Outside a character class, the escape sequence \R matches  any  Unicode
+        Outside  a  character class, the escape sequence \R matches any Unicode
         newline sequence. This is an extension to Perl. In non-UTF-8 mode \R is
         equivalent to the following:
           (?>\r\n|\n|\x0b|\f|\r|\x85)
-        This is an example of an "atomic group", details  of  which  are  given
+        This  is  an  example  of an "atomic group", details of which are given
         below.  This particular group matches either the two-character sequence
-        CR followed by LF, or  one  of  the  single  characters  LF  (linefeed,
+        CR  followed  by  LF,  or  one  of  the single characters LF (linefeed,
         U+000A), VT (vertical tab, U+000B), FF (formfeed, U+000C), CR (carriage
         return, U+000D), or NEL (next line, U+0085). The two-character sequence
         is treated as a single unit that cannot be split.
-        In  UTF-8  mode, two additional characters whose codepoints are greater
+        In UTF-8 mode, two additional characters whose codepoints  are  greater
         than 255 are added: LS (line separator, U+2028) and PS (paragraph sepa-
-        rator,  U+2029).   Unicode character property support is not needed for
+        rator, U+2029).  Unicode character property support is not  needed  for
         these characters to be recognized.
         Inside a character class, \R matches the letter "R".
-Line 2975 
 BACKSLASH
+Line 2996 
 BACKSLASH
     Unicode character properties
         When PCRE is built with Unicode character property support, three addi-
-        tional  escape  sequences  to  match character properties are available
+        tional escape sequences to match  character  properties  are  available
         when UTF-8 mode is selected. They are:
           \p{xx}   a character with the xx property
           \P{xx}   a character without the xx property
           \X       an extended Unicode sequence
-        The property names represented by xx above are limited to  the  Unicode
+        The  property  names represented by xx above are limited to the Unicode
         script names, the general category properties, and "Any", which matches
         any character (including newline). Other properties such as "InMusical-
-        Symbols"  are  not  currently supported by PCRE. Note that \P{Any} does
+        Symbols" are not currently supported by PCRE. Note  that  \P{Any}  does
         not match any characters, so always causes a match failure.
         Sets of Unicode characters are defined as belonging to certain scripts.
-        A  character from one of these sets can be matched using a script name.
+        A character from one of these sets can be matched using a script  name.
         For example:
           \p{Greek}
           \P{Han}
-        Those that are not part of an identified script are lumped together  as
+        Those  that are not part of an identified script are lumped together as
         "Common". The current list of scripts is:
         Arabic,  Armenian,  Balinese,  Bengali,  Bopomofo,  Braille,  Buginese,
-        Buhid,  Canadian_Aboriginal,  Cherokee,  Common,   Coptic,   Cuneiform,
+        Buhid,   Canadian_Aboriginal,   Cherokee,  Common,  Coptic,  Cuneiform,
         Cypriot, Cyrillic, Deseret, Devanagari, Ethiopic, Georgian, Glagolitic,
-        Gothic, Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew,  Hira-
+        Gothic,  Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew, Hira-
-        gana,  Inherited,  Kannada,  Katakana,  Kharoshthi,  Khmer, Lao, Latin,
+        gana, Inherited, Kannada,  Katakana,  Kharoshthi,  Khmer,  Lao,  Latin,
         Limbu,  Linear_B,  Malayalam,  Mongolian,  Myanmar,  New_Tai_Lue,  Nko,
-        Ogham,  Old_Italic,  Old_Persian, Oriya, Osmanya, Phags_Pa, Phoenician,
+        Ogham, Old_Italic, Old_Persian, Oriya, Osmanya,  Phags_Pa,  Phoenician,
         Runic,  Shavian,  Sinhala,  Syloti_Nagri,  Syriac,  Tagalog,  Tagbanwa,
         Tai_Le, Tamil, Telugu, Thaana, Thai, Tibetan, Tifinagh, Ugaritic, Yi.
-        Each  character has exactly one general category property, specified by
+        Each character has exactly one general category property, specified  by
         a two-letter abbreviation. For compatibility with Perl, negation can be
-        specified  by  including a circumflex between the opening brace and the
+        specified by including a circumflex between the opening brace  and  the
         property name. For example, \p{^Lu} is the same as \P{Lu}.
         If only one letter is specified with \p or \P, it includes all the gen-
-        eral  category properties that start with that letter. In this case, in
+        eral category properties that start with that letter. In this case,  in
-        the absence of negation, the curly brackets in the escape sequence  are
+        the  absence of negation, the curly brackets in the escape sequence are
         optional; these two examples have the same effect:
           \p{L}
-Line 3067 
 BACKSLASH
+Line 3088 
 BACKSLASH
           Zp    Paragraph separator
           Zs    Space separator
-        The  special property L& is also supported: it matches a character that
+        The special property L& is also supported: it matches a character  that
-        has the Lu, Ll, or Lt property, in other words, a letter  that  is  not
+        has  the  Lu,  Ll, or Lt property, in other words, a letter that is not
         classified as a modifier or "other".
-        The  long  synonyms  for  these  properties that Perl supports (such as
+        The long synonyms for these properties  that  Perl  supports  (such  as
-        \p{Letter}) are not supported by PCRE, nor is it  permitted  to  prefix
+        \p{Letter})  are  not  supported by PCRE, nor is it permitted to prefix
         any of these properties with "Is".
         No character that is in the Unicode table has the Cn (unassigned) prop-
         erty.  Instead, this property is assumed for any code point that is not
         in the Unicode table.
-        Specifying  caseless  matching  does not affect these escape sequences.
+        Specifying caseless matching does not affect  these  escape  sequences.
         For example, \p{Lu} always matches only upper case letters.
-        The \X escape matches any number of Unicode  characters  that  form  an
+        The  \X  escape  matches  any number of Unicode characters that form an
         extended Unicode sequence. \X is equivalent to
           (?>\PM\pM*)
-        That  is,  it matches a character without the "mark" property, followed
+        That is, it matches a character without the "mark"  property,  followed
-        by zero or more characters with the "mark"  property,  and  treats  the
+        by  zero  or  more  characters with the "mark" property, and treats the
-        sequence  as  an  atomic group (see below).  Characters with the "mark"
+        sequence as an atomic group (see below).  Characters  with  the  "mark"
         property are typically accents that affect the preceding character.
-        Matching characters by Unicode property is not fast, because  PCRE  has
+        Matching  characters  by Unicode property is not fast, because PCRE has
-        to  search  a  structure  that  contains data for over fifteen thousand
+        to search a structure that contains  data  for  over  fifteen  thousand
         characters. That is why the traditional escape sequences such as \d and
         \w do not use Unicode properties in PCRE.
+    Resetting the match start
+        The escape sequence \K, which is a Perl 5.10 feature, causes any previ-
+        ously  matched  characters  not  to  be  included  in the final matched
+        sequence. For example, the pattern:
+          foo\Kbar
+        matches "foobar", but reports that it has matched "bar".  This  feature
+        is  similar  to  a lookbehind assertion (described below).  However, in
+        this case, the part of the subject before the real match does not  have
+        to  be of fixed length, as lookbehind assertions do. The use of \K does
+        not interfere with the setting of captured  substrings.   For  example,
+        when the pattern
+          (foo)\Kbar
+        matches "foobar", the first substring is still set to "foo".
     Simple assertions
         The  final use of backslash is for certain simple assertions. An asser-
-Line 3858 
 BACK REFERENCES
+Line 3898 
 BACK REFERENCES
         matches  "rah  rah"  and  "RAH RAH", but not "RAH rah", even though the
         original capturing subpattern is matched caselessly.
-        Back references to named subpatterns use the Perl  syntax  \k<name>  or
+        There are several different ways of writing back  references  to  named
-        \k'name'  or  the  Python  syntax (?P=name). We could rewrite the above
+        subpatterns.  The  .NET syntax \k{name} and the Perl syntax \k<name> or
-        example in either of the following ways:
+        \k'name' are supported, as is the Python syntax (?P=name). Perl  5.10's
+        unified back reference syntax, in which \g can be used for both numeric
+        and named references, is also supported. We  could  rewrite  the  above
+        example in any of the following ways:
           (?<p1>(?i)rah)\s+\k<p1>
+          (?'p1'(?i)rah)\s+\k{p1}
           (?P<p1>(?i)rah)\s+(?P=p1)
+          (?<p1>(?i)rah)\s+\g{p1}
-        A subpattern that is referenced by  name  may  appear  in  the  pattern
+        A  subpattern  that  is  referenced  by  name may appear in the pattern
         before or after the reference.
-        There  may be more than one back reference to the same subpattern. If a
+        There may be more than one back reference to the same subpattern. If  a
-        subpattern has not actually been used in a particular match,  any  back
+        subpattern  has  not actually been used in a particular match, any back
         references to it always fail. For example, the pattern
           (a|(bc))\2
-        always  fails if it starts to match "a" rather than "bc". Because there
+        always fails if it starts to match "a" rather than "bc". Because  there
-        may be many capturing parentheses in a pattern,  all  digits  following
+        may  be  many  capturing parentheses in a pattern, all digits following
-        the  backslash  are taken as part of a potential back reference number.
+        the backslash are taken as part of a potential back  reference  number.
         If the pattern continues with a digit character, some delimiter must be
-        used  to  terminate  the back reference. If the PCRE_EXTENDED option is
+        used to terminate the back reference. If the  PCRE_EXTENDED  option  is
-        set, this can be whitespace.  Otherwise an  empty  comment  (see  "Com-
+        set,  this  can  be  whitespace.  Otherwise an empty comment (see "Com-
         ments" below) can be used.
-        A  back reference that occurs inside the parentheses to which it refers
+        A back reference that occurs inside the parentheses to which it  refers
-        fails when the subpattern is first used, so, for example,  (a\1)  never
+        fails  when  the subpattern is first used, so, for example, (a\1) never
-        matches.   However,  such references can be useful inside repeated sub-
+        matches.  However, such references can be useful inside  repeated  sub-
         patterns. For example, the pattern
           (a|b\1)+
         matches any number of "a"s and also "aba", "ababbaa" etc. At each iter-
-        ation  of  the  subpattern,  the  back  reference matches the character
+        ation of the subpattern,  the  back  reference  matches  the  character
-        string corresponding to the previous iteration. In order  for  this  to
+        string  corresponding  to  the previous iteration. In order for this to
-        work,  the  pattern must be such that the first iteration does not need
+        work, the pattern must be such that the first iteration does  not  need
-        to match the back reference. This can be done using alternation, as  in
+        to  match the back reference. This can be done using alternation, as in
         the example above, or by a quantifier with a minimum of zero.
  ASSERTIONS
-        An  assertion  is  a  test on the characters following or preceding the
+        An assertion is a test on the characters  following  or  preceding  the
-        current matching point that does not actually consume  any  characters.
+        current  matching  point that does not actually consume any characters.
-        The  simple  assertions  coded  as  \b, \B, \A, \G, \Z, \z, ^ and $ are
+        The simple assertions coded as \b, \B, \A, \G, \Z,  \z,  ^  and  $  are
         described above.
-        More complicated assertions are coded as  subpatterns.  There  are  two
+        More  complicated  assertions  are  coded as subpatterns. There are two
-        kinds:  those  that  look  ahead of the current position in the subject
+        kinds: those that look ahead of the current  position  in  the  subject
-        string, and those that look  behind  it.  An  assertion  subpattern  is
+        string,  and  those  that  look  behind  it. An assertion subpattern is
-        matched  in  the  normal way, except that it does not cause the current
+        matched in the normal way, except that it does not  cause  the  current
         matching position to be changed.
-        Assertion subpatterns are not capturing subpatterns,  and  may  not  be
+        Assertion  subpatterns  are  not  capturing subpatterns, and may not be
-        repeated,  because  it  makes no sense to assert the same thing several
+        repeated, because it makes no sense to assert the  same  thing  several
-        times. If any kind of assertion contains capturing  subpatterns  within
+        times.  If  any kind of assertion contains capturing subpatterns within
-        it,  these are counted for the purposes of numbering the capturing sub-
+        it, these are counted for the purposes of numbering the capturing  sub-
         patterns in the whole pattern.  However, substring capturing is carried
-        out  only  for  positive assertions, because it does not make sense for
+        out only for positive assertions, because it does not  make  sense  for
         negative assertions.
     Lookahead assertions
-Line 3925 
 ASSERTIONS
+Line 3970 
 ASSERTIONS
           \w+(?=;)
-        matches  a word followed by a semicolon, but does not include the semi-
+        matches a word followed by a semicolon, but does not include the  semi-
         colon in the match, and
           foo(?!bar)
-        matches any occurrence of "foo" that is not  followed  by  "bar".  Note
+        matches  any  occurrence  of  "foo" that is not followed by "bar". Note
         that the apparently similar pattern
           (?!foo)bar
-        does  not  find  an  occurrence  of "bar" that is preceded by something
+        does not find an occurrence of "bar"  that  is  preceded  by  something
-        other than "foo"; it finds any occurrence of "bar" whatsoever,  because
+        other  than "foo"; it finds any occurrence of "bar" whatsoever, because
         the assertion (?!foo) is always true when the next three characters are
         "bar". A lookbehind assertion is needed to achieve the other effect.
         If you want to force a matching failure at some point in a pattern, the
-        most  convenient  way  to  do  it  is with (?!) because an empty string
+        most convenient way to do it is  with  (?!)  because  an  empty  string
-        always matches, so an assertion that requires there not to be an  empty
+        always  matches, so an assertion that requires there not to be an empty
         string must always fail.
     Lookbehind assertions
-        Lookbehind  assertions start with (?<= for positive assertions and (?<!
+        Lookbehind assertions start with (?<= for positive assertions and  (?<!
         for negative assertions. For example,
           (?<!foo)bar
-        does find an occurrence of "bar" that is not  preceded  by  "foo".  The
+        does  find  an  occurrence  of "bar" that is not preceded by "foo". The
-        contents  of  a  lookbehind  assertion are restricted such that all the
+        contents of a lookbehind assertion are restricted  such  that  all  the
         strings it matches must have a fixed length. However, if there are sev-
-        eral  top-level  alternatives,  they  do  not all have to have the same
+        eral top-level alternatives, they do not all  have  to  have  the  same
         fixed length. Thus
           (?<=bullock|donkey)
-Line 3964 
 ASSERTIONS
+Line 4009 
 ASSERTIONS
           (?<!dogs?|cats?)
-        causes an error at compile time. Branches that match  different  length
+        causes  an  error at compile time. Branches that match different length
-        strings  are permitted only at the top level of a lookbehind assertion.
+        strings are permitted only at the top level of a lookbehind  assertion.
-        This is an extension compared with  Perl  (at  least  for  5.8),  which
+        This  is  an  extension  compared  with  Perl (at least for 5.8), which
-        requires  all branches to match the same length of string. An assertion
+        requires all branches to match the same length of string. An  assertion
         such as
           (?<=ab(c|de))
-        is not permitted, because its single top-level  branch  can  match  two
+        is  not  permitted,  because  its single top-level branch can match two
-        different  lengths,  but  it is acceptable if rewritten to use two top-
+        different lengths, but it is acceptable if rewritten to  use  two  top-
         level branches:
           (?<=abc|abde)
-        The implementation of lookbehind assertions is, for  each  alternative,
+        In some cases, the Perl 5.10 escape sequence \K (see above) can be used
-        to  temporarily  move the current position back by the fixed length and
+        instead of a lookbehind assertion; this is not restricted to  a  fixed-
+        length.
+        The  implementation  of lookbehind assertions is, for each alternative,
+        to temporarily move the current position back by the fixed  length  and
         then try to match. If there are insufficient characters before the cur-
         rent position, the assertion fails.
         PCRE does not allow the \C escape (which matches a single byte in UTF-8
-        mode) to appear in lookbehind assertions, because it makes it  impossi-
+        mode)  to appear in lookbehind assertions, because it makes it impossi-
-        ble  to  calculate the length of the lookbehind. The \X and \R escapes,
+        ble to calculate the length of the lookbehind. The \X and  \R  escapes,
         which can match different numbers of bytes, are also not permitted.
-        Possessive quantifiers can  be  used  in  conjunction  with  lookbehind
+        Possessive  quantifiers  can  be  used  in  conjunction with lookbehind
-        assertions  to  specify  efficient  matching  at the end of the subject
+        assertions to specify efficient matching at  the  end  of  the  subject
         string. Consider a simple pattern such as
           abcd$
-        when applied to a long string that does  not  match.  Because  matching
+        when  applied  to  a  long string that does not match. Because matching
         proceeds from left to right, PCRE will look for each "a" in the subject
-        and then see if what follows matches the rest of the  pattern.  If  the
+        and  then  see  if what follows matches the rest of the pattern. If the
         pattern is specified as
           ^.*abcd$
-        the  initial .* matches the entire string at first, but when this fails
+        the initial .* matches the entire string at first, but when this  fails
         (because there is no following "a"), it backtracks to match all but the
-        last  character,  then all but the last two characters, and so on. Once
+        last character, then all but the last two characters, and so  on.  Once
-        again the search for "a" covers the entire string, from right to  left,
+        again  the search for "a" covers the entire string, from right to left,
         so we are no better off. However, if the pattern is written as
           ^.*+(?<=abcd)
-        there  can  be  no backtracking for the .*+ item; it can match only the
+        there can be no backtracking for the .*+ item; it can  match  only  the
-        entire string. The subsequent lookbehind assertion does a  single  test
+        entire  string.  The subsequent lookbehind assertion does a single test
-        on  the last four characters. If it fails, the match fails immediately.
+        on the last four characters. If it fails, the match fails  immediately.
-        For long strings, this approach makes a significant difference  to  the
+        For  long  strings, this approach makes a significant difference to the
         processing time.
     Using multiple assertions
-Line 4021 
 ASSERTIONS
+Line 4070 
 ASSERTIONS
           (?<=\d{3})(?<!999)foo
-        matches  "foo" preceded by three digits that are not "999". Notice that
+        matches "foo" preceded by three digits that are not "999". Notice  that
-        each of the assertions is applied independently at the  same  point  in
+        each  of  the  assertions is applied independently at the same point in
-        the  subject  string.  First  there  is a check that the previous three
+        the subject string. First there is a  check  that  the  previous  three
-        characters are all digits, and then there is  a  check  that  the  same
+        characters  are  all  digits,  and  then there is a check that the same
         three characters are not "999".  This pattern does not match "foo" pre-
-        ceded by six characters, the first of which are  digits  and  the  last
+        ceded  by  six  characters,  the first of which are digits and the last
-        three  of  which  are not "999". For example, it doesn't match "123abc-
+        three of which are not "999". For example, it  doesn't  match  "123abc-
         foo". A pattern to do that is
           (?<=\d{3}...)(?<!999)foo
-        This time the first assertion looks at the  preceding  six  characters,
+        This  time  the  first assertion looks at the preceding six characters,
         checking that the first three are digits, and then the second assertion
         checks that the preceding three characters are not "999".
-Line 4040 
 ASSERTIONS
+Line 4089 
 ASSERTIONS
           (?<=(?<!foo)bar)baz
-        matches an occurrence of "baz" that is preceded by "bar" which in  turn
+        matches  an occurrence of "baz" that is preceded by "bar" which in turn
         is not preceded by "foo", while
           (?<=\d{3}(?!999)...)foo
-        is  another pattern that matches "foo" preceded by three digits and any
+        is another pattern that matches "foo" preceded by three digits and  any
         three characters that are not "999".
  CONDITIONAL SUBPATTERNS
-        It is possible to cause the matching process to obey a subpattern  con-
+        It  is possible to cause the matching process to obey a subpattern con-
-        ditionally  or to choose between two alternative subpatterns, depending
+        ditionally or to choose between two alternative subpatterns,  depending
-        on the result of an assertion, or whether a previous capturing  subpat-
+        on  the result of an assertion, or whether a previous capturing subpat-
-        tern  matched  or not. The two possible forms of conditional subpattern
+        tern matched or not. The two possible forms of  conditional  subpattern
         are
           (?(condition)yes-pattern)
           (?(condition)yes-pattern|no-pattern)
-        If the condition is satisfied, the yes-pattern is used;  otherwise  the
+        If  the  condition is satisfied, the yes-pattern is used; otherwise the
-        no-pattern  (if  present)  is used. If there are more than two alterna-
+        no-pattern (if present) is used. If there are more  than  two  alterna-
         tives in the subpattern, a compile-time error occurs.
-        There are four kinds of condition: references  to  subpatterns,  refer-
+        There  are  four  kinds of condition: references to subpatterns, refer-
         ences to recursion, a pseudo-condition called DEFINE, and assertions.
     Checking for a used subpattern by number
-        If  the  text between the parentheses consists of a sequence of digits,
+        If the text between the parentheses consists of a sequence  of  digits,
-        the condition is true if the capturing subpattern of  that  number  has
+        the  condition  is  true if the capturing subpattern of that number has
-        previously matched.
+        previously matched. An alternative notation is to  precede  the  digits
+        with a plus or minus sign. In this case, the subpattern number is rela-
+        tive rather than absolute.  The most recently opened parentheses can be
+        referenced  by  (?(-1),  the  next most recent by (?(-2), and so on. In
+        looping constructs it can also make sense to refer to subsequent groups
+        with constructs such as (?(+2).
         Consider  the  following  pattern, which contains non-significant white
         space to make it more readable (assume the PCRE_EXTENDED option) and to
-Line 4090 
 CONDITIONAL SUBPATTERNS
+Line 4144 
 CONDITIONAL SUBPATTERNS
         other  words,  this  pattern  matches  a  sequence  of non-parentheses,
         optionally enclosed in parentheses.
+        If you were embedding this pattern in a larger one,  you  could  use  a
+        relative reference:
+          ...other stuff... ( \( )?    [^()]+    (?(-1) \) ) ...
+        This  makes  the  fragment independent of the parentheses in the larger
+        pattern.
     Checking for a used subpattern by name
         Perl uses the syntax (?(<name>)...) or (?('name')...)  to  test  for  a
-Line 4231 
 RECURSIVE PATTERNS
+Line 4293 
 RECURSIVE PATTERNS
           ( \( ( (?>[^()]+) | (?1) )* \) )
         We  have  put the pattern into parentheses, and caused the recursion to
-        refer to them instead of the whole pattern. In a larger pattern,  keep-
+        refer to them instead of the whole pattern.
-        ing  track  of parenthesis numbers can be tricky. It may be more conve-
-        nient to use named parentheses instead. The Perl  syntax  for  this  is
+        In a larger pattern,  keeping  track  of  parenthesis  numbers  can  be
-        (?&name);  PCRE's  earlier syntax (?P>name) is also supported. We could
+        tricky.  This is made easier by the use of relative references. (A Perl
-        rewrite the above example as follows:
+.10 feature.)  Instead of (?1) in the  pattern  above  you  can  write
+        (?-2) to refer to the second most recently opened parentheses preceding
+        the recursion. In other  words,  a  negative  number  counts  capturing
+        parentheses leftwards from the point at which it is encountered.
+        It  is  also  possible  to refer to subsequently opened parentheses, by
+        writing references such as (?+2). However, these  cannot  be  recursive
+        because  the  reference  is  not inside the parentheses that are refer-
+        enced. They are always "subroutine" calls, as  described  in  the  next
+        section.
+        An  alternative  approach is to use named parentheses instead. The Perl
+        syntax for this is (?&name); PCRE's earlier syntax  (?P>name)  is  also
+        supported. We could rewrite the above example as follows:
           (?<pn> \( ( (?>[^()]+) | (?&pn) )* \) )
-        If there is more than one subpattern with the same name,  the  earliest
+        If  there  is more than one subpattern with the same name, the earliest
-        one  is used. This particular example pattern contains nested unlimited
+        one is used.
-        repeats, and so the use of atomic grouping for matching strings of non-
-        parentheses  is  important when applying the pattern to strings that do
+        This particular example pattern that we have been looking  at  contains
-        not match. For example, when this pattern is applied to
+        nested  unlimited repeats, and so the use of atomic grouping for match-
+        ing strings of non-parentheses is important when applying  the  pattern
+        to strings that do not match. For example, when this pattern is applied
+        to
           (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
-Line 4293 
 SUBPATTERNS AS SUBROUTINES
+Line 4371 
 SUBPATTERNS AS SUBROUTINES
         If the syntax for a recursive subpattern reference (either by number or
         by  name)  is used outside the parentheses to which it refers, it oper-
         ates like a subroutine in a programming language. The "called"  subpat-
-        tern  may  be defined before or after the reference. An earlier example
+        tern may be defined before or after the reference. A numbered reference
-        pointed out that the pattern
+        can be absolute or relative, as in these examples:
+          (...(absolute)...)...(?2)...
+          (...(relative)...)...(?-1)...
+          (...(?+1)...(relative)...
+        An earlier example pointed out that the pattern
           (sens|respons)e and \1ibility
-Line 4316 
 SUBPATTERNS AS SUBROUTINES
+Line 4400 
 SUBPATTERNS AS SUBROUTINES
         case-independence are fixed when the subpattern is defined. They cannot
         be changed for different calls. For example, consider this pattern:
-          (abc)(?i:(?1))
+          (abc)(?i:(?-1))
         It matches "abcabc". It does not match "abcABC" because the  change  of
         processing option does not affect the called subpattern.
-Line 4371 
 AUTHOR
+Line 4455 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 29 May 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 4452 
 RESTRICTED PATTERNS FOR PCRE_PARTIAL
+Line 4536 
 RESTRICTED PATTERNS FOR PCRE_PARTIAL
         If PCRE_PARTIAL is set for a pattern  that  does  not  conform  to  the
         restrictions,  pcre_exec() returns the error code PCRE_ERROR_BADPARTIAL
-        (-13).
+        (-13).  You can use the PCRE_INFO_OKPARTIAL call to pcre_fullinfo()  to
+        find out if a compiled pattern can be used for partial matching.
  EXAMPLE OF PARTIAL MATCHING USING PCRETEST
-        If the escape sequence \P is present  in  a  pcretest  data  line,  the
+        If  the  escape  sequence  \P  is  present in a pcretest data line, the
         PCRE_PARTIAL flag is used for the match. Here is a run of pcretest that
         uses the date example quoted above:
-Line 4474 
 EXAMPLE OF PARTIAL MATCHING USING PCRETE
+Line 4559 
 EXAMPLE OF PARTIAL MATCHING USING PCRETE
           data> j\P
           No match
-        The first data string is matched  completely,  so  pcretest  shows  the
+        The  first  data  string  is  matched completely, so pcretest shows the
-        matched  substrings.  The  remaining four strings do not match the com-
+        matched substrings. The remaining four strings do not  match  the  com-
-        plete pattern, but the first two are partial matches.  The  same  test,
+        plete  pattern,  but  the first two are partial matches. The same test,
-        using  pcre_dfa_exec()  matching  (by means of the \D escape sequence),
+        using pcre_dfa_exec() matching (by means of the  \D  escape  sequence),
         produces the following output:
             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
-Line 4492 
 EXAMPLE OF PARTIAL MATCHING USING PCRETE
+Line 4577 
 EXAMPLE OF PARTIAL MATCHING USING PCRETE
           data> j\P\D
           No match
-        Notice that in this case the portion of the string that was matched  is
+        Notice  that in this case the portion of the string that was matched is
         made available.
  MULTI-SEGMENT MATCHING WITH pcre_dfa_exec()
         When a partial match has been found using pcre_dfa_exec(), it is possi-
-        ble to continue the match by  providing  additional  subject  data  and
+        ble  to  continue  the  match  by providing additional subject data and
-        calling  pcre_dfa_exec()  again  with the same compiled regular expres-
+        calling pcre_dfa_exec() again with the same  compiled  regular  expres-
         sion, this time setting the PCRE_DFA_RESTART option. You must also pass
-        the  same working space as before, because this is where details of the
+        the same working space as before, because this is where details of  the
-        previous partial match are stored. Here is an example  using  pcretest,
+        previous  partial  match are stored. Here is an example using pcretest,
         using the \R escape sequence to set the PCRE_DFA_RESTART option (\P and
         \D are as above):
-Line 4513 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
+Line 4598 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
           data> n05\R\D
 : n05
-        The first call has "23ja" as the subject, and requests  partial  match-
+        The  first  call has "23ja" as the subject, and requests partial match-
-        ing;  the  second  call  has  "n05"  as  the  subject for the continued
+        ing; the second call  has  "n05"  as  the  subject  for  the  continued
-        (restarted) match.  Notice that when the match is  complete,  only  the
+        (restarted)  match.   Notice  that when the match is complete, only the
-        last  part  is  shown;  PCRE  does not retain the previously partially-
+        last part is shown; PCRE does  not  retain  the  previously  partially-
-        matched string. It is up to the calling program to do that if it  needs
+        matched  string. It is up to the calling program to do that if it needs
         to.
-        You  can  set  PCRE_PARTIAL  with  PCRE_DFA_RESTART to continue partial
+        You can set PCRE_PARTIAL  with  PCRE_DFA_RESTART  to  continue  partial
         matching over multiple segments. This facility can be used to pass very
-        long  subject  strings to pcre_dfa_exec(). However, some care is needed
+        long subject strings to pcre_dfa_exec(). However, some care  is  needed
         for certain types of pattern.
-. If the pattern contains tests for the beginning or end  of  a  line,
+.  If  the  pattern contains tests for the beginning or end of a line,
-        you  need  to pass the PCRE_NOTBOL or PCRE_NOTEOL options, as appropri-
+        you need to pass the PCRE_NOTBOL or PCRE_NOTEOL options,  as  appropri-
-        ate, when the subject string for any call does not contain  the  begin-
+        ate,  when  the subject string for any call does not contain the begin-
         ning or end of a line.
-.  If  the  pattern contains backward assertions (including \b or \B),
+. If the pattern contains backward assertions (including  \b  or  \B),
-        you need to arrange for some overlap in the subject  strings  to  allow
+        you  need  to  arrange for some overlap in the subject strings to allow
-        for  this.  For  example, you could pass the subject in chunks that are
+        for this. For example, you could pass the subject in  chunks  that  are
-bytes long, but in a buffer of 700 bytes, with the starting  offset
+ bytes long, but in a buffer of 700 bytes, with the starting offset
         set to 200 and the previous 200 bytes at the start of the buffer.
-.  Matching a subject string that is split into multiple segments does
+. Matching a subject string that is split into multiple segments  does
-        not always produce exactly the same result as matching over one  single
+        not  always produce exactly the same result as matching over one single
-        long  string.   The  difference arises when there are multiple matching
+        long string.  The difference arises when there  are  multiple  matching
-        possibilities, because a partial match result is given only when  there
+        possibilities,  because a partial match result is given only when there
-        are  no completed matches in a call to pcre_dfa_exec(). This means that
+        are no completed matches in a call to pcre_dfa_exec(). This means  that
-        as soon as the shortest match has been found,  continuation  to  a  new
+        as  soon  as  the  shortest match has been found, continuation to a new
         subject segment is no longer possible.  Consider this pcretest example:
             re> /dog(sbody)?/
-Line 4553 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
+Line 4638 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
 : dogsbody
 : dog
-        The pattern matches the words "dog" or "dogsbody". When the subject  is
+        The  pattern matches the words "dog" or "dogsbody". When the subject is
-        presented  in  several  parts  ("do" and "gsb" being the first two) the
+        presented in several parts ("do" and "gsb" being  the  first  two)  the
-        match stops when "dog" has been found, and it is not possible  to  con-
+        match  stops  when "dog" has been found, and it is not possible to con-
-        tinue.  On  the  other  hand,  if  "dogsbody"  is presented as a single
+        tinue. On the other hand,  if  "dogsbody"  is  presented  as  a  single
         string, both matches are found.
-        Because of this phenomenon, it does not usually make  sense  to  end  a
+        Because  of  this  phenomenon,  it does not usually make sense to end a
         pattern that is going to be matched in this way with a variable repeat.
 . Patterns that contain alternatives at the top level which do not all
-Line 4568 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
+Line 4653 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
 |3789
-        If the first part of the subject is "ABC123", a partial  match  of  the
+        If  the  first  part of the subject is "ABC123", a partial match of the
-        first  alternative  is found at offset 3. There is no partial match for
+        first alternative is found at offset 3. There is no partial  match  for
         the second alternative, because such a match does not start at the same
-        point  in  the  subject  string. Attempting to continue with the string
+        point in the subject string. Attempting to  continue  with  the  string
         "789" does not yield a match because only those alternatives that match
-        at  one point in the subject are remembered. The problem arises because
+        at one point in the subject are remembered. The problem arises  because
-        the start of the second alternative matches within the  first  alterna-
+        the  start  of the second alternative matches within the first alterna-
         tive. There is no problem with anchored patterns or patterns such as:
 |ABCD
-Line 4591 
 AUTHOR
+Line 4676 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 04 June 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------

 Legend:



Removed from v.155
 


changed lines


 
Added in v.172
 Legend:



Removed from v.155
 


changed lines


 
Added in v.172
-Removed from v.155
+Added in v.172

	ViewVC Help
Powered by ViewVC 1.1.5