In perl.git, the branch blead has been updated
<https://perl5.git.perl.org/perl.git/commitdiff/44abdc3a8a76a7ca901b7f513b33f72cc9f21495?hp=3c1b037f652c65ec12fbb10e4d08e0b1599b6aa5>
- Log -----------------------------------------------------------------
commit 44abdc3a8a76a7ca901b7f513b33f72cc9f21495
Author: Karl Williamson <k...@cpan.org>
Date: Sun Dec 16 12:38:28 2018 -0700
regcomp.c: Tighten embedded patterns in regex sets
In the (?[ ... ]) regex sets features, one can embed another compiled
regex set pattern. Such compiled patterns always have a flag of '^',
which we weren't looking for prior to this commit. That meant that
uncompiled patterns would be mistaken for compiled ones.
commit 1c484ed4bdbb071c7ad4fc9a259c1aa027d27719
Author: Karl Williamson <k...@cpan.org>
Date: Sun Dec 16 12:36:02 2018 -0700
perlrecharclass: Clarify embedding in regex sets
commit fdec910a2ad5554e242cfe0137c49704248664df
Author: Karl Williamson <k...@cpan.org>
Date: Sun Dec 16 12:33:15 2018 -0700
perlre: Italicize variable text
-----------------------------------------------------------------------
Summary of changes:
pod/perlre.pod | 2 +-
pod/perlrecharclass.pod | 30 +++++++++++++++---------------
regcomp.c | 19 ++++++++-----------
t/re/reg_mesg.t | 4 ++--
4 files changed, 26 insertions(+), 29 deletions(-)
diff --git a/pod/perlre.pod b/pod/perlre.pod
index e97d6c87df..5329df2f86 100644
--- a/pod/perlre.pod
+++ b/pod/perlre.pod
@@ -2051,7 +2051,7 @@ Full syntax: C<< (?(<name>)then|else) >>
Checks whether the pattern matches (or does not match, for the C<"!">
variants).
-Full syntax: C<< (?(?=lookahead)then|else) >>
+Full syntax: C<< (?(?=I<lookahead>)I<then>|I<else>) >>
=item C<(?{ I<CODE> })>
diff --git a/pod/perlrecharclass.pod b/pod/perlrecharclass.pod
index 225a092c05..fb9dc432b0 100644
--- a/pod/perlrecharclass.pod
+++ b/pod/perlrecharclass.pod
@@ -1171,8 +1171,15 @@ closing C<])> characters.
Just as in all regular expressions, the pattern can be built up by
including variables that are interpolated at regex compilation time.
-Care must be taken to ensure that you are getting what you expect. For
-example:
+But its best to compile each sub-component.
+
+ my $thai_or_lao = qr/(?[ \p{Thai} + \p{Lao} ])/;
+ my $lower = qr/(?[ \p{Lower} + \p{Digit} ])/;
+
+When these are embedded in another pattern, what they match does not
+change, regardless of parenthesization or what modifiers are in effect
+in that outer pattern. If you fail to compile the subcomponents, you
+can get some nasty surprises. For example:
my $thai_or_lao = '\p{Thai} + \p{Lao}';
...
@@ -1182,10 +1189,10 @@ compiles to
qr/(?[ \p{Digit} & \p{Thai} + \p{Lao} ])/;
-But this does not have the effect that someone reading the code would
-likely expect, as the intersection applies just to C<\p{Thai}>,
-excluding the Laotian. Pitfalls like this can be avoided by
-parenthesizing the component pieces:
+But this does not have the effect that someone reading the source code
+would likely expect, as the intersection applies just to C<\p{Thai}>,
+excluding the Laotian. Its best to compile the subcomponents, but you
+could also parenthesize the component pieces:
my $thai_or_lao = '( \p{Thai} + \p{Lao} )';
@@ -1194,15 +1201,8 @@ But any modifiers will still apply to all the components:
my $lower = '\p{Lower} + \p{Digit}';
qr/(?[ \p{Greek} & $lower ])/i;
-matches upper case things. You can avoid surprises by making the
-components into instances of this construct by compiling them:
-
- my $thai_or_lao = qr/(?[ \p{Thai} + \p{Lao} ])/;
- my $lower = qr/(?[ \p{Lower} + \p{Digit} ])/;
-
-When these are embedded in another pattern, what they match does not
-change, regardless of parenthesization or what modifiers are in effect
-in that outer pattern.
+matches upper case things. So just, compile the subcomponents, as
+illustrated above.
Due to the way that Perl parses things, your parentheses and brackets
may need to be balanced, even including comments. If you run into any
diff --git a/regcomp.c b/regcomp.c
index 0fc793626f..83e7029d50 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -15822,10 +15822,11 @@ redo_curchar:
case '(':
- if ( RExC_parse < RExC_end - 1
- && (UCHARAT(RExC_parse + 1) == '?'))
+ if ( RExC_parse < RExC_end - 2
+ && UCHARAT(RExC_parse + 1) == '?'
+ && UCHARAT(RExC_parse + 2) == '^')
{
- /* If is a '(?', could be an embedded '(?flags:(?[...])'.
+ /* If is a '(?', could be an embedded '(?^flags:(?[...])'.
* This happens when we have some thing like
*
* my $thai_or_lao = qr/(?[ \p{Thai} + \p{Lao} ])/;
@@ -15843,14 +15844,11 @@ redo_curchar:
RExC_parse += 2; /* Skip past the '(?' */
save_parse = RExC_parse;
- /* Parse any flags for the '(?' */
+ /* Parse the flags for the '(?'. We already know the first
+ * flag to parse is a '^' */
parse_lparen_question_flags(pRExC_state);
- if (RExC_parse == save_parse /* Makes sure there was at
- least one flag (or else
- this embedding wasn't
- compiled) */
- || RExC_parse >= RExC_end - 4
+ if ( RExC_parse >= RExC_end - 4
|| UCHARAT(RExC_parse) != ':'
|| UCHARAT(++RExC_parse) != '('
|| UCHARAT(++RExC_parse) != '?'
@@ -15859,8 +15857,7 @@ redo_curchar:
/* In combination with the above, this moves the
* pointer to the point just after the first erroneous
- * character (or if there are no flags, to where they
- * should have been) */
+ * character. */
if (RExC_parse >= RExC_end - 4) {
RExC_parse = RExC_end;
}
diff --git a/t/re/reg_mesg.t b/t/re/reg_mesg.t
index 81f1441ae2..13a37b534b 100644
--- a/t/re/reg_mesg.t
+++ b/t/re/reg_mesg.t
@@ -261,8 +261,8 @@ my @death =
'm/(?[[a-\pM]])/' => 'False [] range "a-\pM" {#} m/(?[[a-\pM{#}]])/',
'm/(?[[\pM-x]])/' => 'False [] range "\pM-" {#} m/(?[[\pM-{#}x]])/',
'm/(?[[^\N{LATIN CAPITAL LETTER A WITH MACRON AND GRAVE}]])/' => '\N{} in
inverted character class or as a range end-point is restricted to one character
{#} m/(?[[^\N{U+100.300{#}}]])/',
- 'm/(?[ \p{Digit} & (?(?[ \p{Thai} | \p{Lao} ]))])/' => 'Sequence (?(...) not
recognized {#} m/(?[ \p{Digit} & (?({#}?[ \p{Thai} | \p{Lao} ]))])/',
- 'm/(?[ \p{Digit} & (?:(?[ \p{Thai} | \p{Lao} ]))])/' => 'Expecting
\'(?flags:(?[...\' {#} m/(?[ \p{Digit} & (?{#}:(?[ \p{Thai} | \p{Lao} ]))])/',
+ 'm/(?[ \p{Digit} & (?^(?[ \p{Thai} | \p{Lao} ]))])/' => 'Sequence (?^(...)
not recognized {#} m/(?[ \p{Digit} & (?^({#}?[ \p{Thai} | \p{Lao} ]))])/',
+ 'm/(?[ \p{Digit} & (?(?[ \p{Thai} | \p{Lao} ]))])/' => 'Unexpected character
{#} m/(?[ \p{Digit} & (?{#}(?[ \p{Thai} | \p{Lao} ]))])/',
'm/\o{/' => 'Missing right brace on \o{ {#} m/\o{{#}/',
'm/\o/' => 'Missing braces on \o{} {#} m/\o{#}/',
'm/\o{}/' => 'Number with no digits {#} m/\o{}{#}/',
--
Perl5 Master Repository
