Update HTML docs.

doc/html/pcre2api.html

@@ -1914,6 +1914,13 @@ Extra compile options
 <P>
 The option bits that can be set in a compile context by calling the
 <b>pcre2_set_compile_extra_options()</b> function are as follows:
+<pre>
+  PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK
+</pre>
+Since release 10.38 PCRE2 has forbidden the use of \K within lookaround 
+assertions, following Perl's lead. This option is provided to re-enable the 
+previous behaviour (act in positive lookarounds, ignore in negative ones) in 
+case anybody is relying on it.   
 <pre>
   PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES
 </pre>
@@ -4001,7 +4008,7 @@ Cambridge, England.
 </P>
 <br><a name="SEC42" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 28 August 2021
+Last updated: 30 August 2021
 <br>
 Copyright &copy; 1997-2021 University of Cambridge.
 <br>

doc/html/pcre2compat.html

@@ -153,8 +153,10 @@ letters, regardless of case, when case independence is specified.
 </P>
 <P>
 16. From release 5.32.0, Perl locks out the use of \K in lookaround
-assertions. In PCRE2, \K is acted on when it occurs in positive assertions,
+assertions. From release 10.38 PCRE2 does the same by default. However, there
-but is ignored in negative assertions.
+is an option for re-enabling the previous behaviour. When this option is set,
+\K is acted on when it occurs in positive assertions, but is ignored in
+negative assertions.
 </P>
 <P>
 17. PCRE2 provides some extensions to the Perl regular expression facilities.
@@ -237,7 +239,7 @@ AUTHOR
 <P>
 Philip Hazel
 <br>
-University Computing Service
+Retired from University Computing Service
 <br>
 Cambridge, England.
 <br>
@@ -246,9 +248,9 @@ Cambridge, England.
 REVISION
 </b><br>
 <P>
-Last updated: 06 October 2020
+Last updated: 30 August 2021
 <br>
-Copyright &copy; 1997-2019 University of Cambridge.
+Copyright &copy; 1997-2021 University of Cambridge.
 <br>
 <p>
 Return to the <a href="index.html">PCRE2 index page</a>.

doc/html/pcre2demo.html

@@ -234,9 +234,12 @@ pcre2_match_data_create_from_pattern() above. */
 if (rc == 0)
   printf("ovector was not big enough for all the captured substrings\n");
 
-/* We must guard against patterns such as /(?=.\K)/ that use \K in an assertion
+/* Since release 10.38 PCRE2 has locked out the use of \K in lookaround 
-to set the start of a match later than its end. In this demonstration program,
+assertions. However, there is an option to re-enable the old behaviour. If that 
-we just detect this case and give up. */
+is set, it is possible to run patterns such as /(?=.\K)/ that use \K in an
+assertion to set the start of a match later than its end. In this demonstration
+program, we show how to detect this case, but it shouldn't arise because the 
+option is never set. */
 
 if (ovector[0] > ovector[1])
   {

doc/html/pcre2pattern.html

@@ -1175,9 +1175,11 @@ For example, when the pattern
 matches "foobar", the first substring is still set to "foo".
 </P>
 <P>
-Perl used to document that the use of \K within lookaround assertions is "not
+From version 5.32.0 Perl forbids the use of \K in lookaround assertions. From 
-well defined", but from version 5.32.0 Perl does not support this usage at all.
+release 10.38 PCRE2 also forbids this by default. However, the 
-In PCRE2, \K is acted upon when it occurs inside positive assertions, but is
+PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK option can be used when calling 
+<b>pcre2_compile()</b> to re-enable the previous behaviour. When this option is 
+set, \K is acted upon when it occurs inside positive assertions, but is
 ignored in negative assertions. Note that when a pattern such as (?=ab\K)
 matches, the reported start of the match can be greater than the end of the
 match. Using \K in a lookbehind assertion at the start of a pattern can also
@@ -3845,16 +3847,16 @@ there is a backtrack at the outer level.
 <P>
 Philip Hazel
 <br>
-University Computing Service
+Retired from University Computing Service
 <br>
 Cambridge, England.
 <br>
 </P>
 <br><a name="SEC32" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 06 October 2020
+Last updated: 30 August 2021
 <br>
-Copyright &copy; 1997-2020 University of Cambridge.
+Copyright &copy; 1997-2021 University of Cambridge.
 <br>
 <p>
 Return to the <a href="index.html">PCRE2 index page</a>.

doc/html/pcre2syntax.html

@@ -429,6 +429,9 @@ but some of them use Unicode properties if PCRE2_UCP is set. You can use
 <pre>
   \K          set reported start of match
 </pre>
+From release 10.38 \K is not permitted by default in lookaround assertions, 
+for compatibility with Perl. However, if the PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK
+option is set, the previous behaviour is re-enabled. When this option is set,
 \K is honoured in positive assertions, but ignored in negative ones.
 </P>
 <br><a name="SEC12" href="#TOC1">ALTERNATION</a><br>
@@ -682,16 +685,16 @@ delimiter }. To encode the ending delimiter within the string, double it.
 <P>
 Philip Hazel
 <br>
-University Computing Service
+Retired from University Computing Service
 <br>
 Cambridge, England.
 <br>
 </P>
 <br><a name="SEC29" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 28 December 2019
+Last updated: 30 August 2021
 <br>
-Copyright &copy; 1997-2019 University of Cambridge.
+Copyright &copy; 1997-2021 University of Cambridge.
 <br>
 <p>
 Return to the <a href="index.html">PCRE2 index page</a>.

doc/html/pcre2test.html

@@ -59,12 +59,7 @@ patterns, and the subject lines specify PCRE2 function options, control how the
 subject is processed, and what output is produced.
 </P>
 <P>
-As the original fairly simple PCRE library evolved, it acquired many different
+There are many obscure modifiers, some of which are specifically designed for
-features, and as a result, the original <b>pcretest</b> program ended up with a
-lot of options in a messy, arcane syntax for testing all the features. The
-move to the new PCRE2 API provided an opportunity to re-implement the test
-program as <b>pcre2test</b>, with a cleaner modifier syntax. Nevertheless, there
-are still many obscure modifiers, some of which are specifically designed for
 use in conjunction with the test script and data files that are distributed as
 part of PCRE2. All the modifiers are documented here, some without much
 justification, but many of them are unlikely to be of use except when testing
@@ -89,10 +84,10 @@ names used in the libraries have a suffix _8, _16, or _32, as appropriate.
 <br><a name="SEC3" href="#TOC1">INPUT ENCODING</a><br>
 <P>
 Input to <b>pcre2test</b> is processed line by line, either by calling the C
-library's <b>fgets()</b> function, or via the <b>libreadline</b> library. In some
+library's <b>fgets()</b> function, or via the <b>libreadline</b> or <b>libedit</b> 
-Windows environments character 26 (hex 1A) causes an immediate end of file, and
+library. In some Windows environments character 26 (hex 1A) causes an immediate
-no further data is read, so this character should be avoided unless you really
+end of file, and no further data is read, so this character should be avoided
-want that action.
+unless you really want that action.
 </P>
 <P>
 The input is processed using using C's string functions, so must not
@@ -514,11 +509,11 @@ A pattern can be followed by a modifier list (details below).
 </P>
 <br><a name="SEC9" href="#TOC1">SUBJECT LINE SYNTAX</a><br>
 <P>
-Before each subject line is passed to <b>pcre2_match()</b> or
+Before each subject line is passed to <b>pcre2_match()</b>,
-<b>pcre2_dfa_match()</b>, leading and trailing white space is removed, and the
+<b>pcre2_dfa_match()</b>, or <b>pcre2_jit_match()</b>, leading and trailing white
-line is scanned for backslash escapes, unless the <b>subject_literal</b>
+space is removed, and the line is scanned for backslash escapes, unless the
-modifier was set for the pattern. The following provide a means of encoding
+<b>subject_literal</b> modifier was set for the pattern. The following provide a
-non-printing characters in a visible way:
+means of encoding non-printing characters in a visible way:
 <pre>
   \a         alarm (BEL, \x07)
   \b         backspace (\x08)
@@ -615,6 +610,7 @@ way <b>pcre2_compile()</b> behaves. See
 for a description of the effects of these options.
 <pre>
       allow_empty_class         set PCRE2_ALLOW_EMPTY_CLASS
+      allow_lookaround_bsk      set PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK 
       allow_surrogate_escapes   set PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES
       alt_bsux                  set PCRE2_ALT_BSUX
       alt_circumflex            set PCRE2_ALT_CIRCUMFLEX
@@ -2126,7 +2122,7 @@ Cambridge, England.
 </P>
 <br><a name="SEC21" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 28 August 2021
+Last updated: 30 August 2021
 <br>
 Copyright &copy; 1997-2021 University of Cambridge.
 <br>

doc/pcre2demo.3

@@ -234,9 +234,12 @@ pcre2_match_data_create_from_pattern() above. */
 if (rc == 0)
   printf("ovector was not big enough for all the captured substrings\en");
 
-/* We must guard against patterns such as /(?=.\eK)/ that use \eK in an assertion
+/* Since release 10.38 PCRE2 has locked out the use of \eK in lookaround 
-to set the start of a match later than its end. In this demonstration program,
+assertions. However, there is an option to re-enable the old behaviour. If that 
-we just detect this case and give up. */
+is set, it is possible to run patterns such as /(?=.\eK)/ that use \eK in an
+assertion to set the start of a match later than its end. In this demonstration
+program, we show how to detect this case, but it shouldn't arise because the 
+option is never set. */
 
 if (ovector[0] > ovector[1])
   {

doc/pcre2test.txt

@@ -24,17 +24,11 @@ SYNOPSIS
        tion  options, control how the subject is processed, and what output is
        produced.
 
-       As the original fairly simple PCRE library evolved,  it  acquired  many
+       There are many obscure modifiers, some of which  are  specifically  de-
-       different  features,  and  as  a  result, the original pcretest program
+       signed  for use in conjunction with the test script and data files that
-       ended up with a lot of options in a messy, arcane  syntax  for  testing
+       are distributed as part of PCRE2.  All  the  modifiers  are  documented
-       all the features. The move to the new PCRE2 API provided an opportunity
+       here, some without much justification, but many of them are unlikely to
-       to re-implement the test program as pcre2test, with a cleaner  modifier
+       be of use except when testing the libraries.
-       syntax.  Nevertheless,  there are still many obscure modifiers, some of
-       which are specifically designed for use in conjunction  with  the  test
-       script  and  data  files that are distributed as part of PCRE2. All the
-       modifiers are documented here, some  without  much  justification,  but
-       many  of  them  are  unlikely  to be of use except when testing the li-
-       braries.
 
 
 PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
@@ -58,10 +52,10 @@ PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
 INPUT ENCODING
 
        Input  to  pcre2test is processed line by line, either by calling the C
-       library's fgets() function, or via the  libreadline  library.  In  some
+       library's fgets() function, or via the libreadline or libedit  library.
-       Windows  environments  character 26 (hex 1A) causes an immediate end of
+       In  some Windows environments character 26 (hex 1A) causes an immediate
-       file, and no further data is read, so this character should be  avoided
+       end of file, and no further data is read, so this character  should  be
-       unless you really want that action.
+       avoided unless you really want that action.
 
        The  input  is  processed using using C's string functions, so must not
        contain binary zeros, even though in  Unix-like  environments,  fgets()
@@ -454,11 +448,11 @@ PATTERN SYNTAX
 
 SUBJECT LINE SYNTAX
 
-       Before   each   subject   line   is   passed   to   pcre2_match()    or
+       Before each subject line is passed to pcre2_match(), pcre2_dfa_match(),
-       pcre2_dfa_match(), leading and trailing white space is removed, and the
+       or  pcre2_jit_match(), leading and trailing white space is removed, and
-       line is scanned for backslash escapes, unless the subject_literal modi-
+       the line is scanned for backslash escapes, unless  the  subject_literal
-       fier was set for the pattern. The following provide a means of encoding
+       modifier  was set for the pattern. The following provide a means of en-
-       non-printing characters in a visible way:
+       coding non-printing characters in a visible way:
 
          \a         alarm (BEL, \x07)
          \b         backspace (\x08)
@@ -553,6 +547,7 @@ PATTERN MODIFIERS
        options.
 
              allow_empty_class         set PCRE2_ALLOW_EMPTY_CLASS
+             allow_lookaround_bsk      set PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK
              allow_surrogate_escapes   set PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES
              alt_bsux                  set PCRE2_ALT_BSUX
              alt_circumflex            set PCRE2_ALT_CIRCUMFLEX
@@ -1938,5 +1933,5 @@ AUTHOR
 
 REVISION
 
-       Last updated: 28 August 2021
+       Last updated: 30 August 2021
        Copyright (c) 1997-2021 University of Cambridge.