This convenience function finds, for a compiled pattern, the first and last -entries for a given name in the table that translates capturing parenthesis -names into numbers. +entries for a given name in the table that translates capture group names into +numbers.
code Compiled regular expression name Name whose entries required diff --git a/doc/html/pcre2api.html b/doc/html/pcre2api.html index 018a077..bbfaeaa 100644 --- a/doc/html/pcre2api.html +++ b/doc/html/pcre2api.html @@ -49,7 +49,7 @@ please consult the man page, in case the conversion went wrong.
PCRE2_DUPNAMES-If this bit is set, names used to identify capturing subpatterns need not be -unique. This can be helpful for certain types of pattern when it is known that -only one instance of the named subpattern can ever be matched. There are more -details of named subpatterns below; see also the +If this bit is set, names used to identify capture groups need not be unique. +This can be helpful for certain types of pattern when it is known that only one +instance of the named group can ever be matched. There are more details of +named capture groups below; see also the pcre2pattern documentation.
@@ -1526,11 +1526,11 @@ the end of the subject.
If this bit is set, most white space characters in the pattern are totally
ignored except when escaped or inside a character class. However, white space
is not allowed within sequences such as (?> that introduce various
-parenthesized subpatterns, nor within numerical quantifiers such as {1,3}.
-Ignorable white space is permitted between an item and a following quantifier
-and between a quantifier and a following + that indicates possessiveness.
-PCRE2_EXTENDED is equivalent to Perl's /x option, and it can be changed within
-a pattern by a (?x) option setting.
+parenthesized groups, nor within numerical quantifiers such as {1,3}. Ignorable
+white space is permitted between an item and a following quantifier and between
+a quantifier and a following + that indicates possessiveness. PCRE2_EXTENDED is
+equivalent to Perl's /x option, and it can be changed within a pattern by a
+(?x) option setting.
When PCRE2 is compiled without Unicode support, PCRE2_EXTENDED recognizes as
@@ -1606,7 +1606,7 @@ error.
PCRE2_MATCH_UNSET_BACKREF
-If this option is set, a backreference to an unset subpattern group matches an
+If this option is set, a backreference to an unset capture group matches an
empty string (by default this causes the current matching alternative to fail).
A pattern such as (\1)(a) succeeds when this option is set (assuming it can
find an "a" in the subject), whereas it fails by default, for Perl
@@ -1668,7 +1668,7 @@ If this option is set, it disables the use of numbered capturing parentheses in
the pattern. Any opening parenthesis that is not followed by ? behaves as if it
were followed by ?: but named parentheses can still be used for capturing (and
they acquire numbers in the usual way). This is the same as Perl's /n option.
-Note that, when this option is set, references to capturing groups
+Note that, when this option is set, references to capture groups
(backreferences or recursion/subroutine calls) may only refer to named groups,
though the reference can be by name or by number.
@@ -1687,7 +1687,7 @@ purposes.
If this option is set, it disables an optimization that is applied when .* is
the first significant item in a top-level branch of a pattern, and all the
other branches also start with .* or with \A or \G or ^. The optimization is
-automatically disabled for .* if it is inside an atomic group or a capturing
+automatically disabled for .* if it is inside an atomic group or a capture
group that is the subject of a backreference, or if the pattern contains
(*PRUNE) or (*SKIP). When the optimization is not disabled, such a pattern is
automatically anchored if PCRE2_DOTALL is set for all the .* items and
@@ -2066,7 +2066,7 @@ When .* is the first significant item, anchoring is possible only when all the
following are true:
.* is not in an atomic group
- .* is not in a capturing group that is the subject of a backreference
+ .* is not in a capture group that is the subject of a backreference
PCRE2_DOTALL is in force for .*
Neither (*PRUNE) nor (*SKIP) appears in the pattern
PCRE2_NO_DOTSTAR_ANCHOR is not set
@@ -2077,12 +2077,12 @@ options returned for PCRE2_INFO_ALLOPTIONS.
PCRE2_INFO_BACKREFMAX
Return the number of the highest backreference in the pattern. The third
-argument should point to an uint32_t variable. Named subpatterns acquire
-numbers as well as names, and these count towards the highest backreference.
-Backreferences such as \4 or \g{12} match the captured characters of the
-given group, but in addition, the check that a capturing group is set in a
-conditional subpattern such as (?(3)a|b) is also a backreference. Zero is
-returned if there are no backreferences.
+argument should point to an uint32_t variable. Named capture groups
+acquire numbers as well as names, and these count towards the highest
+backreference. Backreferences such as \4 or \g{12} match the captured
+characters of the given group, but in addition, the check that a capture
+group is set in a conditional group such as (?(3)a|b) is also a backreference.
+Zero is returned if there are no backreferences.
PCRE2_INFO_BSR
@@ -2093,9 +2093,9 @@ that \R matches only CR, LF, or CRLF.
PCRE2_INFO_CAPTURECOUNT
-Return the highest capturing subpattern number in the pattern. In patterns
-where (?| is not used, this is also the total number of capturing subpatterns.
-The third argument should point to an uint32_t variable.
+Return the highest capture group number in the pattern. In patterns where (?|
+is not used, this is also the total number of capture groups. The third
+argument should point to an uint32_t variable.
PCRE2_INFO_DEPTHLIMIT
@@ -2143,7 +2143,7 @@ Return the size (in bytes) of the data frames that are used to remember
backtracking positions when the pattern is processed by pcre2_match()
without the use of JIT. The third argument should point to a size_t
variable. The frame size depends on the number of capturing parentheses in the
-pattern. Each additional capturing group adds two PCRE2_SIZE variables.
+pattern. Each additional capture group adds two PCRE2_SIZE variables.
PCRE2_INFO_HASBACKSLASHC
@@ -2267,20 +2267,20 @@ the parenthesis number. The rest of the entry is the corresponding name, zero
terminated.
-The names are in alphabetical order. If (?| is used to create multiple groups
-with the same number, as described in the
-section on duplicate subpattern numbers
+The names are in alphabetical order. If (?| is used to create multiple capture
+groups with the same number, as described in the
+section on duplicate group numbers
in the
pcre2pattern
page, the groups may be given the same name, but there is only one entry in the
table. Different names for groups of the same number are not permitted.
-Duplicate names for subpatterns with different numbers are permitted, but only
-if PCRE2_DUPNAMES is set. They appear in the table in the order in which they
-were found in the pattern. In the absence of (?| this is the order of
+Duplicate names for capture groups with different numbers are permitted, but
+only if PCRE2_DUPNAMES is set. They appear in the table in the order in which
+they were found in the pattern. In the absence of (?| this is the order of
increasing number; when (?| is used this is not necessarily the case because
-later subpatterns may have lower numbers.
+later capture groups may have lower numbers.
As a simple example of the name/number table, consider the following pattern
@@ -2289,16 +2289,16 @@ space - including newlines - is ignored):
(?<date> (?<year>(\d\d)?\d\d) - (?<month>\d\d) - (?<day>\d\d) )
-There are four named subpatterns, so the table has four entries, and each entry
-in the table is eight bytes long. The table is as follows, with non-printing
-bytes shows in hexadecimal, and undefined bytes shown as ??:
+There are four named capture groups, so the table has four entries, and each
+entry in the table is eight bytes long. The table is as follows, with
+non-printing bytes shows in hexadecimal, and undefined bytes shown as ??:
00 01 d a t e 00 ??
00 05 d a y 00 ?? ??
00 04 m o n t h 00
00 02 y e a r 00 ??
-When writing code to extract data from named subpatterns using the
+When writing code to extract data from named capture groups using the
name-to-number map, remember that the length of the entries is likely to be
different for each compiled pattern.
@@ -2741,12 +2741,12 @@ valid newline sequence and explicit \r or \n escapes appear in the pattern.
In general, a pattern matches a certain portion of the subject, and in
addition, further substrings from the subject may be picked out by
parenthesized parts of the pattern. Following the usage in Jeffrey Friedl's
-book, this is called "capturing" in what follows, and the phrase "capturing
-subpattern" or "capturing group" is used for a fragment of a pattern that picks
-out a substring. PCRE2 supports several other kinds of parenthesized subpattern
-that do not cause substrings to be captured. The pcre2_pattern_info()
-function can be used to find out how many capturing subpatterns there are in a
-compiled pattern.
+book, this is called "capturing" in what follows, and the phrase "capture
+group" (Perl terminology) is used for a fragment of a pattern that picks out a
+substring. PCRE2 supports several other kinds of parenthesized group that do
+not cause substrings to be captured. The pcre2_pattern_info() function
+can be used to find out how many capture groups there are in a compiled
+pattern.
You can use auxiliary functions for accessing captured substrings
@@ -2795,9 +2795,8 @@ For example, if the pattern (?=ab\K) is matched against "ab", the start and
end offset values for the match are 2 and 0.
-If a capturing subpattern group is matched repeatedly within a single match
-operation, it is the last portion of the subject that it matched that is
-returned.
+If a capture group is matched repeatedly within a single match operation, it is
+the last portion of the subject that it matched that is returned.
If the ovector is too small to hold all the captured substring offsets, as much
@@ -2806,21 +2805,20 @@ substrings are not of interest, pcre2_match() may be called with a match
data block whose ovector is of minimum length (that is, one pair).
-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 return from the
-function is 4, and subpatterns 1 and 3 are matched, but 2 is not. When this
-happens, both values in the offset pairs corresponding to unused subpatterns
-are set to PCRE2_UNSET.
+It is possible for capture group number n+1 to match some part of the
+subject when group n has not been used at all. For example, if the string
+"abc" is matched against the pattern (a|(z))(bc) the return from the function
+is 4, and groups 1 and 3 are matched, but 2 is not. When this happens, both
+values in the offset pairs corresponding to unused groups are set to
+PCRE2_UNSET.
-Offset values that correspond to unused subpatterns at the end of the
-expression are also set to PCRE2_UNSET. For example, if the string "abc" is
-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 capturing
-subpattern number is 1. The offsets for for the second and third capturing
-subpatterns (assuming the vector is large enough, of course) are set to
-PCRE2_UNSET.
+Offset values that correspond to unused groups at the end of the expression are
+also set to PCRE2_UNSET. For example, if the string "abc" is matched against
+the pattern (abc)(x(yz)?)? groups 2 and 3 are not matched. The return from the
+function is 2, because the highest used capture group number is 1. The offsets
+for for the second and third capture groupss (assuming the vector is large
+enough, of course) are set to PCRE2_UNSET.
Elements in the ovector that do not correspond to capturing parentheses in the
@@ -2993,11 +2991,11 @@ as NULL.
This error is returned when pcre2_match() detects a recursion loop within
the pattern. Specifically, it means that either the whole pattern or a
-subpattern has been called recursively for the second time at the same position
-in the subject string. Some simple patterns that might do this are detected and
-faulted at compile time, but more complicated cases, in particular mutual
-recursions between two different subpatterns, cannot be detected until matching
-is attempted.
+capture group has been called recursively for the second time at the same
+position in the subject string. Some simple patterns that might do this are
+detected and faulted at compile time, but more complicated cases, in particular
+mutual recursions between two different groups, cannot be detected until
+matching is attempted.
OBTAINING A TEXTUAL ERROR MESSAGE
@@ -3074,7 +3072,7 @@ The pcre2_substring_copy_bynumber() function copies a captured substring
into a supplied buffer, whereas pcre2_substring_get_bynumber() copies it
into new memory, obtained using the same memory allocation function that was
used for the match data block. The first two arguments of these functions are a
-pointer to the match data block and a capturing group number.
+pointer to the match data block and a capture group number.
The final arguments of pcre2_substring_copy_bynumber() are a pointer to
@@ -3150,9 +3148,9 @@ calling pcre2_substring_list_free().
If this function encounters a substring that is unset, which can happen when
-capturing subpattern number n+1 matches some part of the subject, but
-subpattern n has not been used at all, it returns an empty string. This
-can be distinguished from a genuine zero-length substring by inspecting the
+capture group number n+1 matches some part of the subject, but group
+n has not been used at all, it returns an empty string. This can be
+distinguished from a genuine zero-length substring by inspecting the
appropriate offset in the ovector, which contain PCRE2_UNSET for unset
substrings, or by calling pcre2_substring_length_bynumber().
@@ -3182,21 +3180,21 @@ For example, for this pattern:
(a+)b(?<xxx>\d+)...
-the number of the subpattern called "xxx" is 2. If the name is known to be
+the number of the capture group called "xxx" is 2. If the name is known to be
unique (PCRE2_DUPNAMES was not set), you can find the number from the name by
calling pcre2_substring_number_from_name(). The first argument is the
compiled pattern, and the second is the name. The yield of the function is the
-subpattern number, PCRE2_ERROR_NOSUBSTRING if there is no subpattern of that
-name, or PCRE2_ERROR_NOUNIQUESUBSTRING if there is more than one subpattern of
-that name. Given the number, you can extract the substring directly from the
-ovector, or use one of the "bynumber" functions described above.
+group number, PCRE2_ERROR_NOSUBSTRING if there is no group with that name, or
+PCRE2_ERROR_NOUNIQUESUBSTRING if there is more than one group with that name.
+Given the number, you can extract the substring directly from the ovector, or
+use one of the "bynumber" functions described above.
For convenience, there are also "byname" functions that correspond to the
"bynumber" functions, the only difference being that the second argument is a
name instead of a number. If PCRE2_DUPNAMES is set and there are duplicate
names, these functions scan all the groups with the given name, and return the
-first named string that is set.
+captured substring from the first named group that is set.
If there are no groups with the given name, PCRE2_ERROR_NOSUBSTRING is
@@ -3207,13 +3205,13 @@ set, PCRE2_ERROR_UNSET is returned.
Warning: If the pattern uses the (?| feature to set up multiple
-subpatterns with the same number, as described in the
-section on duplicate subpattern numbers
+capture groups with the same number, as described in the
+section on duplicate group numbers
in the
pcre2pattern
-page, you cannot use names to distinguish the different subpatterns, because
+page, you cannot use names to distinguish the different capture groups, because
names are not included in the compiled code. The matching process uses only
-numbers. For this reason, the use of different names for subpatterns of the
+numbers. For this reason, the use of different names for groups with the
same number causes an error at compile time.
CREATING A NEW STRING WITH SUBSTITUTIONS
@@ -3276,7 +3274,7 @@ length is in code units, not bytes.
In the replacement string, which is interpreted as a UTF string in UTF mode,
and is checked for UTF validity unless the PCRE2_NO_UTF_CHECK option is set, a
dollar character is an escape character that can specify the insertion of
-characters from capturing groups or names from (*MARK) or other control verbs
+characters from capture groups or names from (*MARK) or other control verbs
in the pattern. The following forms are always recognized:
$$ insert a dollar character
@@ -3345,13 +3343,13 @@ efficient to allocate a large buffer and free the excess afterwards, instead of
using PCRE2_SUBSTITUTE_OVERFLOW_LENGTH.
-PCRE2_SUBSTITUTE_UNKNOWN_UNSET causes references to capturing groups that do
+PCRE2_SUBSTITUTE_UNKNOWN_UNSET causes references to capture groups that do
not appear in the pattern to be treated as unset groups. This option should be
used with care, because it means that a typo in a group name or number no
longer causes the PCRE2_ERROR_NOSUBSTRING error.
-PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capturing groups (including unknown
+PCRE2_SUBSTITUTE_UNSET_EMPTY causes unset capture groups (including unknown
groups when PCRE2_SUBSTITUTE_UNKNOWN_UNSET is set) to be treated as empty
strings when inserted as described above. If this option is not set, an attempt
to insert an unset group causes the PCRE2_ERROR_UNSET error. This option does
@@ -3379,7 +3377,7 @@ terminating a \Q quoted sequence) reverts to no case forcing. The sequences
\u and \l force the next character (if it is a letter) to upper or lower
case, respectively, and then the state automatically reverts to no case
forcing. Case forcing applies to all inserted characters, including those from
-captured groups and letters within \Q...\E quoted sequences.
+capture groups and letters within \Q...\E quoted sequences.
Note that case forcing sequences such as \U...\E do not nest. For example,
@@ -3388,7 +3386,8 @@ effect.
The second effect of setting PCRE2_SUBSTITUTE_EXTENDED is to add more
-flexibility to group substitution. The syntax is similar to that used by Bash:
+flexibility to capture group substitution. The syntax is similar to that used
+by Bash:
${<n>:-<string>}
${<n>:+<string1>:<string2>}
@@ -3518,20 +3517,21 @@ PCRE2_SUBSTITUTE_GLOBAL is not set), the the rest of the input is copied to the
output and the call to pcre2_substitute() exits, returning the number of
matches so far.
-
DUPLICATE SUBPATTERN NAMES
+
DUPLICATE CAPTURE GROUP NAMES
int pcre2_substring_nametable_scan(const pcre2_code *code,
PCRE2_SPTR name, PCRE2_SPTR *first, PCRE2_SPTR *last);
-When a pattern is compiled with the PCRE2_DUPNAMES option, names for
-subpatterns are not required to be unique. Duplicate names are always allowed
-for subpatterns with the same number, created by using the (?| feature. Indeed,
-if such subpatterns are named, they are required to use the same names.
+When a pattern is compiled with the PCRE2_DUPNAMES option, names for capture
+groups are not required to be unique. Duplicate names are always allowed for
+groups with the same number, created by using the (?| feature. Indeed, if such
+groups are named, they are required to use the same names.
-Normally, patterns with duplicate names are such that in any one match, only
-one of the named subpatterns participates. An example is shown in the
+Normally, patterns that use duplicate names are such that in any one match,
+only one of each set of identically-named groups participates. An example is
+shown in the
pcre2pattern
documentation.
@@ -3703,9 +3703,8 @@ the three matched strings are
On success, the yield of the function is a number greater than zero, which is
the number of matched substrings. The offsets of the substrings are returned in
the ovector, and can be extracted by number in the same way as for
-pcre2_match(), but the numbers bear no relation to any capturing groups
-that may exist in the pattern, because DFA matching does not support group
-capture.
+pcre2_match(), but the numbers bear no relation to any capture groups
+that may exist in the pattern, because DFA matching does not support capturing.
Calls to the convenience functions that extract substrings by name
@@ -3747,7 +3746,7 @@ a backreference.
This return is given if pcre2_dfa_match() encounters a condition item
that uses a backreference for the condition, or a test for recursion in a
-specific group. These are not supported.
+specific capture group. These are not supported.
PCRE2_ERROR_DFA_WSSIZE
@@ -3756,9 +3755,9 @@ This return is given if pcre2_dfa_match() runs out of space in the
PCRE2_ERROR_DFA_RECURSE
-When a recursive subpattern is processed, the matching function calls itself
-recursively, using private memory for the ovector and workspace. This
-error is given if the internal ovector is not large enough. This should be
+When a recursion or subroutine call is processed, the matching function calls
+itself recursively, using private memory for the ovector and workspace.
+This error is given if the internal ovector is not large enough. This should be
extremely rare, as a vector of size 1000 is used.
PCRE2_ERROR_DFA_BADRESTART
@@ -3785,7 +3784,7 @@ Cambridge, England.
REVISION
-Last updated: 04 January 2019
+Last updated: 04 February 2019
Copyright © 1997-2019 University of Cambridge.
diff --git a/doc/html/pcre2callout.html b/doc/html/pcre2callout.html
index bc26812..899a476 100644
--- a/doc/html/pcre2callout.html
+++ b/doc/html/pcre2callout.html
@@ -151,7 +151,7 @@ branch, automatic anchoring occurs if all branches are anchorable.
This optimization is disabled, however, if .* is in an atomic group or if there
-is a backreference to the capturing group in which it appears. It is also
+is a backreference to the capture group in which it appears. It is also
disabled if the pattern contains (*PRUNE) or (*SKIP). However, the presence of
callouts does not affect it.
@@ -354,8 +354,8 @@ callout before an assertion such as (?=ab) the length is 3. For an an
alternation bar or a closing parenthesis, the length is one, unless a closing
parenthesis is followed by a quantifier, in which case its length is included.
(This changed in release 10.23. In earlier releases, before an opening
-parenthesis the length was that of the entire subpattern, and before an
-alternation bar or a closing parenthesis the length was zero.)
+parenthesis the length was that of the entire group, and before an alternation
+bar or a closing parenthesis the length was zero.)
The pattern_position and next_item_length fields are intended to
@@ -471,9 +471,9 @@ Cambridge, England.
REVISION
-Last updated: 17 September 2018
+Last updated: 03 February 2019
-Copyright © 1997-2018 University of Cambridge.
+Copyright © 1997-2019 University of Cambridge.
Return to the PCRE2 index page.
diff --git a/doc/html/pcre2compat.html b/doc/html/pcre2compat.html
index f593204..f110e33 100644
--- a/doc/html/pcre2compat.html
+++ b/doc/html/pcre2compat.html
@@ -36,10 +36,9 @@ assertion just once). Perl allows some repeat quantifiers on other assertions,
for example, \b* (but not \b{3}), but these do not seem to have any use.
-3. Capturing subpatterns that occur inside negative lookaround assertions are
-counted, but their entries in the offsets vector are set only when a negative
-assertion is a condition that has a matching branch (that is, the condition is
-false).
+3. Capture groups that occur inside negative lookaround assertions are counted,
+but their entries in the offsets vector are set only when a negative assertion
+is a condition that has a matching branch (that is, the condition is false).
4. The following Perl escape sequences are not supported: \F, \l, \L, \u,
@@ -94,13 +93,13 @@ to PCRE2 release 10.23, but from release 10.30 this changed, and backtracking
into subroutine calls is now supported, as in Perl.
-9. If any of the backtracking control verbs are used in a subpattern that is
-called as a subroutine (whether or not recursively), their effect is confined
-to that subpattern; it does not extend to the surrounding pattern. This is not
-always the case in Perl. In particular, if (*THEN) is present in a group that
-is called as a subroutine, its action is limited to that group, even if the
-group does not contain any | characters. Note that such subpatterns are
-processed as anchored at the point where they are tested.
+9. If any of the backtracking control verbs are used in a group that is called
+as a subroutine (whether or not recursively), their effect is confined to that
+group; it does not extend to the surrounding pattern. This is not always the
+case in Perl. In particular, if (*THEN) is present in a group that is called as
+a subroutine, its action is limited to that group, even if the group does not
+contain any | characters. Note that such groups are processed as anchored
+at the point where they are tested.
10. If a pattern contains more than one backtracking control verb, the first
@@ -120,22 +119,21 @@ the pattern /^(a(b)?)+$/ in Perl leaves $2 unset, but in PCRE2 it is set to
"b".
-13. PCRE2's handling of duplicate subpattern numbers and duplicate subpattern
-names is not as general as Perl's. This is a consequence of the fact the PCRE2
-works internally just with numbers, using an external table to translate
-between numbers and names. In particular, a pattern such as (?|(?<a>A)|(?<b>B),
-where the two capturing parentheses have the same number but different names,
-is not supported, and causes an error at compile time. If it were allowed, it
-would not be possible to distinguish which parentheses matched, because both
-names map to capturing subpattern number 1. To avoid this confusing situation,
-an error is given at compile time.
+13. PCRE2's handling of duplicate capture group numbers and names is not as
+general as Perl's. This is a consequence of the fact the PCRE2 works internally
+just with numbers, using an external table to translate between numbers and
+names. In particular, a pattern such as (?|(?<a>A)|(?<b>B), where the two
+capture groups have the same number but different names, is not supported, and
+causes an error at compile time. If it were allowed, it would not be possible
+to distinguish which group matched, because both names map to capture group
+number 1. To avoid this confusing situation, an error is given at compile time.
14. Perl used to recognize comments in some places that PCRE2 does not, for
-example, between the ( and ? at the start of a subpattern. If the /x modifier
-is set, Perl allowed white space between ( and ? though the latest Perls give
-an error (for a while it was just deprecated). There may still be some cases
-where Perl behaves differently.
+example, between the ( and ? at the start of a group. If the /x modifier is
+set, Perl allowed white space between ( and ? though the latest Perls give an
+error (for a while it was just deprecated). There may still be some cases where
+Perl behaves differently.
15. Perl, when in warning mode, gives warnings for character classes such as
@@ -235,9 +233,9 @@ Cambridge, England.
REVISION
-Last updated: 28 July 2018
+Last updated: 03 February 2019
-Copyright © 1997-2018 University of Cambridge.
+Copyright © 1997-2019 University of Cambridge.
Return to the PCRE2 index page.
diff --git a/doc/html/pcre2limits.html b/doc/html/pcre2limits.html
index d90cdc3..c8bc01b 100644
--- a/doc/html/pcre2limits.html
+++ b/doc/html/pcre2limits.html
@@ -50,17 +50,17 @@ All values in repeating quantifiers must be less than 65536.
The maximum length of a lookbehind assertion is 65535 characters.
-There is no limit to the number of parenthesized subpatterns, but there can be
-no more than 65535 capturing subpatterns. There is, however, a limit to the
-depth of nesting of parenthesized subpatterns of all kinds. This is imposed in
-order to limit the amount of system stack used at compile time. The default
-limit can be specified when PCRE2 is built; if not, the default is set to 250.
-An application can change this limit by calling pcre2_set_parens_nest_limit()
-to set the limit in a compile context.
+There is no limit to the number of parenthesized groups, but there can be no
+more than 65535 capture groups, and there is a limit to the depth of nesting of
+parenthesized subpatterns of all kinds. This is imposed in order to limit the
+amount of system stack used at compile time. The default limit can be specified
+when PCRE2 is built; if not, the default is set to 250. An application can
+change this limit by calling pcre2_set_parens_nest_limit() to set the limit in
+a compile context.
-The maximum length of name for a named subpattern is 32 code units, and the
-maximum number of named subpatterns is 10000.
+The maximum length of name for a named capture group is 32 code units, and the
+maximum number of such groups is 10000.
The maximum length of a name in a (*MARK), (*PRUNE), (*SKIP), or (*THEN) verb
@@ -86,9 +86,9 @@ Cambridge, England.
REVISION
-Last updated: 30 March 2017
+Last updated: 02 February 2019
-Copyright © 1997-2017 University of Cambridge.
+Copyright © 1997-2019 University of Cambridge.
Return to the PCRE2 index page.
diff --git a/doc/html/pcre2pattern.html b/doc/html/pcre2pattern.html
index 7ccb32f..d57dcea 100644
--- a/doc/html/pcre2pattern.html
+++ b/doc/html/pcre2pattern.html
@@ -26,18 +26,18 @@ please consult the man page, in case the conversion went wrong.
-This document discusses the patterns that are supported by PCRE2 when its main -matching function, pcre2_match(), is used. PCRE2 also has an alternative -matching function, pcre2_dfa_match(), which matches using a different -algorithm that is not Perl-compatible. Some of the features discussed below are -not available when DFA matching is used. The advantages and disadvantages of -the alternative function, and how it differs from the normal function, are -discussed in the +This document discusses the regular expression patterns that are supported by +PCRE2 when its main matching function, pcre2_match(), is used. PCRE2 also +has an alternative matching function, pcre2_dfa_match(), which matches +using a different algorithm that is not Perl-compatible. Some of the features +discussed below are not available when DFA matching is used. The advantages and +disadvantages of the alternative function, and how it differs from the normal +function, are discussed in the pcre2matching page.
@@ -183,8 +183,8 @@ also an explicit memory limit that can be set.These facilities are provided to catch runaway matches that are provoked by -patterns with huge matching trees (a typical example is a pattern with nested -unlimited repeats applied to a long string that does not match). When one of +patterns with huge matching trees. A common example is a pattern with nested +unlimited repeats applied to a long string that does not match. When one of these limits is reached, pcre2_match() gives an error return. The limits can also be set by items at the start of the pattern of the form
@@ -290,10 +290,10 @@ caseless matching is specified (the PCRE2_CASELESS option), letters are matched independently of case.Part of a pattern that is in square brackets is called a "character class". In @@ -323,7 +320,7 @@ a character class the only metacharacters are: \ general escape character ^ negate the class, but only if the first character - indicates character range - [ POSIX character class (only if followed by POSIX syntax) + [ POSIX character class (if followed by POSIX syntax) ] terminates the character class The following sections describe the use of each of the metacharacters. @@ -331,7 +328,7 @@ The following sections describe the use of each of the metacharacters.-The power of regular expressions comes from the ability to include 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. +The power of regular expressions comes from the ability to include wild cards, +character classes, 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 recognized @@ -307,14 +307,11 @@ are as follows: . match any character except newline (by default) [ start character class definition | start of alternative branch - ( start subpattern - ) end subpattern - ? extends the meaning of ( - also 0 or 1 quantifier - also quantifier minimizer + ( start group or control verb + ) end group or control verb * 0 or more quantifier - + 1 or more quantifier - also "possessive quantifier" + + 1 or more quantifier; also "possessive quantifier" + ? 0 or 1 quantifier; also quantifier minimizer { start min/max quantifier
The backslash character has several uses. Firstly, if it is followed by a -character that is not a number or a letter, it takes away any special meaning +character that is not a digit or a letter, it takes away any special meaning that character may have. This use of backslash as an escape character applies both inside and outside character classes.
@@ -343,7 +340,7 @@ precede a non-alphanumeric with backslash to specify that it stands for itself. In particular, if you want to match a backslash, you write \\.-In a UTF mode, only ASCII numbers and letters have any special meaning after a +In a UTF mode, only ASCII digits and letters have any special meaning after a backslash. All other characters (in particular, those whose code points are greater than 127) are treated as literals.
@@ -355,13 +352,13 @@ escaping backslash can be used to include a white space or # character as part of the pattern.-If you want to remove the special meaning from a sequence of characters, you -can do so by putting them between \Q and \E. This is different from Perl in -that $ and @ are handled as literals in \Q...\E sequences in PCRE2, whereas -in Perl, $ and @ cause variable interpolation. Also, Perl does "double-quotish -backslash interpolation" on any backslashes between \Q and \E which, its -documentation says, "may lead to confusing results". PCRE2 treats a backslash -between \Q and \E just like any other character. Note the following examples: +If you want to treat all characters in a sequence as literals, you can do so by +putting them between \Q and \E. This is different from Perl in that $ and @ +are handled as literals in \Q...\E sequences in PCRE2, whereas in Perl, $ and +@ cause variable interpolation. Also, Perl does "double-quotish backslash +interpolation" on any backslashes between \Q and \E which, its documentation +says, "may lead to confusing results". PCRE2 treats a backslash between \Q and +\E just like any other character. Note the following examples: