3 # pragma for controlling the regex engine
7 our $VERSION = "0.06_03";
8 our @ISA = qw(Exporter);
9 our @EXPORT_OK = qw(is_regexp regexp_pattern);
10 our %EXPORT_OK = map { $_ => 1 } @EXPORT_OK;
12 # *** WARNING *** WARNING *** WARNING *** WARNING *** WARNING ***
14 # If you modify these values see comment below!
17 taint => 0x00100000, # HINT_RE_TAINT
18 eval => 0x00200000, # HINT_RE_EVAL
21 # - File::Basename contains a literal for 'taint' as a fallback. If
22 # taint is changed here, File::Basename must be updated as well.
24 # - ExtUtils::ParseXS uses a hardcoded
25 # BEGIN { $^H |= 0x00200000 }
26 # in it to allow re.xs to be built. So if 'eval' is changed here then
27 # ExtUtils::ParseXS must be changed as well.
29 # *** WARNING *** WARNING *** WARNING *** WARNING *** WARNING ***
32 eval { # Ignore errors
35 my $terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning.
36 my $props = $ENV{PERL_RE_TC} || 'md,me,so,se,us,ue';
37 my @props = split /,/, $props;
38 my $colors = join "\t", map {$terminal->Tputs($_,1)} @props;
41 $ENV{PERL_RE_COLORS} = $colors;
44 $ENV{PERL_RE_COLORS} ||= qq'\t\t> <\t> <\t\t';
64 OFFSETSDBG => 0x040000,
66 OPTIMISEM => 0x100000,
70 $flags{All} = $flags{all} = $flags{DUMP} | $flags{EXECUTE};
71 $flags{Extra} = $flags{EXECUTE} | $flags{COMPILE};
72 $flags{More} = $flags{MORE} = $flags{All} | $flags{TRIEC} | $flags{TRIEM} | $flags{STATE};
73 $flags{State} = $flags{DUMP} | $flags{EXECUTE} | $flags{STATE};
74 $flags{TRIE} = $flags{DUMP} | $flags{EXECUTE} | $flags{TRIEC};
80 if ( ! defined($installed) ) {
82 $installed = eval { XSLoader::load('re', $VERSION) } || 0;
83 $installed_error = $@;
92 die "'re' not installed!? ($installed_error)";
94 # We call install() every time, as if we didn't, we wouldn't
95 # "see" any changes to the color environment var since
96 # the last time it was called.
98 # install() returns an integer, which if casted properly
99 # in C resolves to a structure containing the regex
100 # hooks. Setting it to a random integer will guarantee
102 $^H{regcomp} = install();
114 Carp::carp("Useless use of \"re\" pragma");
116 foreach my $idx (0..$#_){
118 if ($s eq 'Debug' or $s eq 'Debugcolor') {
119 setcolor() if $s =~/color/i;
120 ${^RE_DEBUG_FLAGS} = 0 unless defined ${^RE_DEBUG_FLAGS};
121 for my $idx ($idx+1..$#_) {
122 if ($flags{$_[$idx]}) {
124 ${^RE_DEBUG_FLAGS} |= $flags{$_[$idx]};
126 ${^RE_DEBUG_FLAGS} &= ~ $flags{$_[$idx]};
130 Carp::carp("Unknown \"re\" Debug flag '$_[$idx]', possible flags: ",
131 join(", ",sort keys %flags ) );
134 _load_unload($on ? 1 : ${^RE_DEBUG_FLAGS});
136 } elsif ($s eq 'debug' or $s eq 'debugcolor') {
137 setcolor() if $s =~/color/i;
139 } elsif (exists $bitmask{$s}) {
140 $bits |= $bitmask{$s};
141 } elsif ($EXPORT_OK{$s}) {
144 re->export_to_level(2, 're', $s);
147 Carp::carp("Unknown \"re\" subpragma '$s' (known ones are: ",
148 join(', ', map {qq('$_')} 'debug', 'debugcolor', sort keys %bitmask),
162 $^H &= ~ bits(0, @_);
171 re - Perl pragma to alter regular expression behaviour
176 ($x) = ($^X =~ /^(.*)$/s); # $x is tainted here
178 $pat = '(?{ $foo = 1 })';
180 /foo${pat}bar/; # won't fail (when not under -T switch)
183 no re 'taint'; # the default
184 ($x) = ($^X =~ /^(.*)$/s); # $x is not tainted here
186 no re 'eval'; # the default
187 /foo${pat}bar/; # disallowed (with or without -T switch)
190 use re 'debug'; # output debugging info during
191 /^(.*)$/s; # compile and run time
194 use re 'debugcolor'; # same as 'debug', but with colored output
197 use re qw(Debug All); # Finer tuned debugging options.
198 use re qw(Debug More);
199 no re qw(Debug ALL); # Turn of all re debugging in this scope
201 use re qw(is_regexp regexp_pattern); # import utility functions
202 my ($pat,$mods)=regexp_pattern(qr/foo/i);
203 if (is_regexp($obj)) {
204 print "Got regexp: ",
205 scalar regexp_pattern($obj); # just as perl would stringify it
206 } # but no hassle with blessed re's.
209 (We use $^X in these examples because it's tainted by default.)
215 When C<use re 'taint'> is in effect, and a tainted string is the target
216 of a regex, the regex memories (or values returned by the m// operator
217 in list context) are tainted. This feature is useful when regex operations
218 on tainted data aren't meant to extract safe substrings, but to perform
219 other transformations.
223 When C<use re 'eval'> is in effect, a regex is allowed to contain
224 C<(?{ ... })> zero-width assertions even if regular expression contains
225 variable interpolation. That is normally disallowed, since it is a
226 potential security risk. Note that this pragma is ignored when the regular
227 expression is obtained from tainted data, i.e. evaluation is always
228 disallowed with tainted regular expressions. See L<perlre/(?{ code })>.
230 For the purpose of this pragma, interpolation of precompiled regular
231 expressions (i.e., the result of C<qr//>) is I<not> considered variable
236 I<is> allowed if $pat is a precompiled regular expression, even
237 if $pat contains C<(?{ ... })> assertions.
241 When C<use re 'debug'> is in effect, perl emits debugging messages when
242 compiling and using regular expressions. The output is the same as that
243 obtained by running a C<-DDEBUGGING>-enabled perl interpreter with the
244 B<-Dr> switch. It may be quite voluminous depending on the complexity
245 of the match. Using C<debugcolor> instead of C<debug> enables a
246 form of output that can be used to get a colorful display on terminals
247 that understand termcap color sequences. Set C<$ENV{PERL_RE_TC}> to a
248 comma-separated list of C<termcap> properties to use for highlighting
249 strings on/off, pre-point part on/off.
250 See L<perldebug/"Debugging regular expressions"> for additional info.
252 As of 5.9.5 the directive C<use re 'debug'> and its equivalents are
253 lexically scoped, as the other directives are. However they have both
254 compile-time and run-time effects.
256 See L<perlmodlib/Pragmatic Modules>.
260 Similarly C<use re 'Debug'> produces debugging output, the difference
261 being that it allows the fine tuning of what debugging output will be
262 emitted. Options are divided into three groups, those related to
263 compilation, those related to execution and those related to special
264 purposes. The options are as follows:
268 =item Compile related options
274 Turns on all compile related debug options.
278 Turns on debug output related to the process of parsing the pattern.
282 Enables output related to the optimisation phase of compilation.
286 Detailed info about trie compilation.
290 Dump the final program out after it is compiled and optimised.
295 =item Execute related options
301 Turns on all execute related debug options.
305 Turns on debugging of the main matching loop.
309 Extra debugging of how tries execute.
313 Enable debugging of start point optimisations.
317 =item Extra debugging options
323 Turns on all "extra" debugging options.
327 Enable enhanced TRIE debugging. Enhances both TRIEE
332 Enable debugging of states in the engine.
336 Enable debugging of the recursion stack in the engine. Enabling
337 or disabling this option automatically does the same for debugging
338 states as well. This output from this can be quite large.
342 Enable enhanced optimisation debugging and start point optimisations.
343 Probably not useful except when debugging the regex engine itself.
347 Dump offset information. This can be used to see how regops correlate
348 to the pattern. Output format is
350 NODENUM:POSITION[LENGTH]
352 Where 1 is the position of the first char in the string. Note that position
353 can be 0, or larger than the actual length of the pattern, likewise length
358 Enable debugging of offsets information. This emits copious
359 amounts of trace information and doesn't mesh well with other
362 Almost definitely only useful to people hacking
363 on the offsets part of the debug engine.
367 =item Other useful flags
369 These are useful shortcuts to save on the typing.
375 Enable all compile and execute options at once.
379 Enable DUMP and all execute options. Equivalent to:
387 Enable TRIEM and all execute compile and execute options.
393 As of 5.9.5 the directive C<use re 'debug'> and its equivalents are
394 lexically scoped, as the other directives are. However they have both
395 compile-time and run-time effects.
397 =head2 Exportable Functions
399 As of perl 5.9.5 're' debug contains a number of utility functions that
400 may be optionally exported into the callers namespace. They are listed
405 =item is_regexp($ref)
407 Returns true if the argument is a compiled regular expression as returned
408 by C<qr//>, false if it is not.
410 This function will not be confused by overloading or blessing. In
411 internals terms this extracts the regexp pointer out of the
412 PERL_MAGIC_qr structure so it it cannot be fooled.
414 =item regexp_pattern($ref)
416 If the argument is a compiled regular expression as returned by C<qr//>
417 then this function returns the pattern.
419 In list context it returns a two element list, the first element
420 containing the pattern and the second containing the modifiers used when
421 the pattern was compiled.
423 my ($pat,$mods)=regexp_pattern($ref);
425 In scalar context it returns the same as perl would when strigifying a
426 raw qr// with the same pattern inside. If the argument is not a
427 compiled reference then this routine returns false but defined in scalar
428 context, and the empty list in list context. Thus the following
430 if (regexp_pattern($ref) eq '(?i-xsm:foo)')
432 will be warning free regardless of what $ref actually is.
434 Like c<is_regexp> this function will not be confused by overloading
435 or blessing of the object.
441 L<perlmodlib/Pragmatic Modules>.