1624 lines
78 KiB
Plaintext
1624 lines
78 KiB
Plaintext
PCRE2TEST(1) General Commands Manual PCRE2TEST(1)
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NAME
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pcre2test - a program for testing Perl-compatible regular expressions.
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SYNOPSIS
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pcre2test [options] [input file [output file]]
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pcre2test is a test program for the PCRE2 regular expression libraries,
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but it can also be used for experimenting with regular expressions.
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This document describes the features of the test program; for details
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of the regular expressions themselves, see the pcre2pattern documenta-
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tion. For details of the PCRE2 library function calls and their
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options, see the pcre2api documentation.
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The input for pcre2test is a sequence of regular expression patterns
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and subject strings to be matched. There are also command lines for
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setting defaults and controlling some special actions. The output shows
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the result of each match attempt. Modifiers on external or internal
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command lines, the patterns, and the subject lines specify PCRE2 func-
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tion options, control how the subject is processed, and what output is
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produced.
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As the original fairly simple PCRE library evolved, it acquired many
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different features, and as a result, the original pcretest program
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ended up with a lot of options in a messy, arcane syntax for testing
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all the features. The move to the new PCRE2 API provided an opportunity
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to re-implement the test program as pcre2test, with a cleaner modifier
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syntax. Nevertheless, there are still many obscure modifiers, some of
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which are specifically designed for use in conjunction with the test
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script and data files that are distributed as part of PCRE2. All the
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modifiers are documented here, some without much justification, but
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many of them are unlikely to be of use except when testing the
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libraries.
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PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
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Different versions of the PCRE2 library can be built to support charac-
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ter strings that are encoded in 8-bit, 16-bit, or 32-bit code units.
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One, two, or all three of these libraries may be simultaneously
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installed. The pcre2test program can be used to test all the libraries.
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However, its own input and output are always in 8-bit format. When
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testing the 16-bit or 32-bit libraries, patterns and subject strings
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are converted to 16-bit or 32-bit format before being passed to the
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library functions. Results are converted back to 8-bit code units for
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output.
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In the rest of this document, the names of library functions and struc-
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tures are given in generic form, for example, pcre_compile(). The
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actual names used in the libraries have a suffix _8, _16, or _32, as
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appropriate.
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INPUT ENCODING
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Input to pcre2test is processed line by line, either by calling the C
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library's fgets() function, or via the libreadline library. In some
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Windows environments character 26 (hex 1A) causes an immediate end of
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file, and no further data is read, so this character should be avoided
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unless you really want that action.
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The input is processed using using C's string functions, so must not
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contain binary zeroes, even though in Unix-like environments, fgets()
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treats any bytes other than newline as data characters. An error is
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generated if a binary zero is encountered. Subject lines are processed
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for backslash escapes, which makes it possible to include any data
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value in strings that are passed to the library for matching. For pat-
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terns, there is a facility for specifying some or all of the 8-bit
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input characters as hexadecimal pairs, which makes it possible to
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include binary zeros.
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Input for the 16-bit and 32-bit libraries
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When testing the 16-bit or 32-bit libraries, there is a need to be able
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to generate character code points greater than 255 in the strings that
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are passed to the library. For subject lines, backslash escapes can be
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used. In addition, when the utf modifier (see "Setting compilation
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options" below) is set, the pattern and any following subject lines are
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interpreted as UTF-8 strings and translated to UTF-16 or UTF-32 as
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appropriate.
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For non-UTF testing of wide characters, the utf8_input modifier can be
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used. This is mutually exclusive with utf, and is allowed only in
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16-bit or 32-bit mode. It causes the pattern and following subject
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lines to be treated as UTF-8 according to the original definition (RFC
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2279), which allows for character values up to 0x7fffffff. Each charac-
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ter is placed in one 16-bit or 32-bit code unit (in the 16-bit case,
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values greater than 0xffff cause an error to occur).
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UTF-8 (in its original definition) is not capable of encoding values
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greater than 0x7fffffff, but such values can be handled by the 32-bit
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library. When testing this library in non-UTF mode with utf8_input set,
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if any character is preceded by the byte 0xff (which is an illegal byte
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in UTF-8) 0x80000000 is added to the character's value. This is the
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only way of passing such code points in a pattern string. For subject
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strings, using an escape sequence is preferable.
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COMMAND LINE OPTIONS
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-8 If the 8-bit library has been built, this option causes it to
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be used (this is the default). If the 8-bit library has not
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been built, this option causes an error.
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-16 If the 16-bit library has been built, this option causes it
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to be used. If only the 16-bit library has been built, this
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is the default. If the 16-bit library has not been built,
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this option causes an error.
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-32 If the 32-bit library has been built, this option causes it
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to be used. If only the 32-bit library has been built, this
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is the default. If the 32-bit library has not been built,
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this option causes an error.
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-ac Behave as if each pattern has the auto_callout modifier, that
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is, insert automatic callouts into every pattern that is com-
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piled.
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-b Behave as if each pattern has the fullbincode modifier; the
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full internal binary form of the pattern is output after com-
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pilation.
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-C Output the version number of the PCRE2 library, and all
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available information about the optional features that are
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included, and then exit with zero exit code. All other
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options are ignored.
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-C option Output information about a specific build-time option, then
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exit. This functionality is intended for use in scripts such
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as RunTest. The following options output the value and set
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the exit code as indicated:
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ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
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0x15 or 0x25
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0 if used in an ASCII environment
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exit code is always 0
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linksize the configured internal link size (2, 3, or 4)
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exit code is set to the link size
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newline the default newline setting:
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CR, LF, CRLF, ANYCRLF, or ANY
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exit code is always 0
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bsr the default setting for what \R matches:
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ANYCRLF or ANY
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exit code is always 0
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The following options output 1 for true or 0 for false, and
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set the exit code to the same value:
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backslash-C \C is supported (not locked out)
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ebcdic compiled for an EBCDIC environment
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jit just-in-time support is available
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pcre2-16 the 16-bit library was built
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pcre2-32 the 32-bit library was built
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pcre2-8 the 8-bit library was built
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unicode Unicode support is available
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If an unknown option is given, an error message is output;
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the exit code is 0.
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-d Behave as if each pattern has the debug modifier; the inter-
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nal form and information about the compiled pattern is output
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after compilation; -d is equivalent to -b -i.
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-dfa Behave as if each subject line has the dfa modifier; matching
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is done using the pcre2_dfa_match() function instead of the
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default pcre2_match().
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-error number[,number,...]
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Call pcre2_get_error_message() for each of the error numbers
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in the comma-separated list, display the resulting messages
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on the standard output, then exit with zero exit code. The
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numbers may be positive or negative. This is a convenience
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facility for PCRE2 maintainers.
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-help Output a brief summary these options and then exit.
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-i Behave as if each pattern has the info modifier; information
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about the compiled pattern is given after compilation.
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-jit Behave as if each pattern line has the jit modifier; after
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successful compilation, each pattern is passed to the just-
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in-time compiler, if available.
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-pattern modifier-list
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Behave as if each pattern line contains the given modifiers.
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-q Do not output the version number of pcre2test at the start of
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execution.
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-S size On Unix-like systems, set the size of the run-time stack to
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size megabytes.
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-subject modifier-list
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Behave as if each subject line contains the given modifiers.
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-t Run each compile and match many times with a timer, and out-
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put the resulting times per compile or match. When JIT is
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used, separate times are given for the initial compile and
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the JIT compile. You can control the number of iterations
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that are used for timing by following -t with a number (as a
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separate item on the command line). For example, "-t 1000"
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iterates 1000 times. The default is to iterate 500,000 times.
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-tm This is like -t except that it times only the matching phase,
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not the compile phase.
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-T -TM These behave like -t and -tm, but in addition, at the end of
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a run, the total times for all compiles and matches are out-
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put.
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-version Output the PCRE2 version number and then exit.
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DESCRIPTION
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If pcre2test is given two filename arguments, it reads from the first
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and writes to the second. If the first name is "-", input is taken from
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the standard input. If pcre2test is given only one argument, it reads
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from that file and writes to stdout. Otherwise, it reads from stdin and
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writes to stdout.
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When pcre2test is built, a configuration option can specify that it
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should be linked with the libreadline or libedit library. When this is
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done, if the input is from a terminal, it is read using the readline()
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function. This provides line-editing and history facilities. The output
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from the -help option states whether or not readline() will be used.
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The program handles any number of tests, each of which consists of a
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set of input lines. Each set starts with a regular expression pattern,
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followed by any number of subject lines to be matched against that pat-
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tern. In between sets of test data, command lines that begin with # may
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appear. This file format, with some restrictions, can also be processed
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by the perltest.sh script that is distributed with PCRE2 as a means of
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checking that the behaviour of PCRE2 and Perl is the same.
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When the input is a terminal, pcre2test prompts for each line of input,
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using "re>" to prompt for regular expression patterns, and "data>" to
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prompt for subject lines. Command lines starting with # can be entered
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only in response to the "re>" prompt.
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Each subject line is matched separately and independently. If you want
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to do multi-line matches, you have to use the \n escape sequence (or \r
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or \r\n, etc., depending on the newline setting) in a single line of
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input to encode the newline sequences. There is no limit on the length
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of subject lines; the input buffer is automatically extended if it is
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too small. There are replication features that makes it possible to
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generate long repetitive pattern or subject lines without having to
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supply them explicitly.
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An empty line or the end of the file signals the end of the subject
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lines for a test, at which point a new pattern or command line is
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expected if there is still input to be read.
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COMMAND LINES
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In between sets of test data, a line that begins with # is interpreted
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as a command line. If the first character is followed by white space or
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an exclamation mark, the line is treated as a comment, and ignored.
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Otherwise, the following commands are recognized:
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#forbid_utf
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Subsequent patterns automatically have the PCRE2_NEVER_UTF and
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PCRE2_NEVER_UCP options set, which locks out the use of the PCRE2_UTF
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and PCRE2_UCP options and the use of (*UTF) and (*UCP) at the start of
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patterns. This command also forces an error if a subsequent pattern
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contains any occurrences of \P, \p, or \X, which are still supported
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when PCRE2_UTF is not set, but which require Unicode property support
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to be included in the library.
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This is a trigger guard that is used in test files to ensure that UTF
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or Unicode property tests are not accidentally added to files that are
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used when Unicode support is not included in the library. Setting
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PCRE2_NEVER_UTF and PCRE2_NEVER_UCP as a default can also be obtained
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by the use of #pattern; the difference is that #forbid_utf cannot be
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unset, and the automatic options are not displayed in pattern informa-
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tion, to avoid cluttering up test output.
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#load <filename>
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This command is used to load a set of precompiled patterns from a file,
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as described in the section entitled "Saving and restoring compiled
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patterns" below.
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#newline_default [<newline-list>]
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When PCRE2 is built, a default newline convention can be specified.
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This determines which characters and/or character pairs are recognized
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as indicating a newline in a pattern or subject string. The default can
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be overridden when a pattern is compiled. The standard test files con-
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tain tests of various newline conventions, but the majority of the
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tests expect a single linefeed to be recognized as a newline by
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default. Without special action the tests would fail when PCRE2 is com-
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piled with either CR or CRLF as the default newline.
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The #newline_default command specifies a list of newline types that are
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acceptable as the default. The types must be one of CR, LF, CRLF, ANY-
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CRLF, or ANY (in upper or lower case), for example:
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#newline_default LF Any anyCRLF
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If the default newline is in the list, this command has no effect. Oth-
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erwise, except when testing the POSIX API, a newline modifier that
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specifies the first newline convention in the list (LF in the above
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example) is added to any pattern that does not already have a newline
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modifier. If the newline list is empty, the feature is turned off. This
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command is present in a number of the standard test input files.
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When the POSIX API is being tested there is no way to override the
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default newline convention, though it is possible to set the newline
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convention from within the pattern. A warning is given if the posix
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modifier is used when #newline_default would set a default for the non-
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POSIX API.
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#pattern <modifier-list>
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This command sets a default modifier list that applies to all subse-
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quent patterns. Modifiers on a pattern can change these settings.
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#perltest
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The appearance of this line causes all subsequent modifier settings to
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be checked for compatibility with the perltest.sh script, which is used
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to confirm that Perl gives the same results as PCRE2. Also, apart from
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comment lines, none of the other command lines are permitted, because
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they and many of the modifiers are specific to pcre2test, and should
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not be used in test files that are also processed by perltest.sh. The
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#perltest command helps detect tests that are accidentally put in the
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wrong file.
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#pop [<modifiers>]
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#popcopy [<modifiers>]
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These commands are used to manipulate the stack of compiled patterns,
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as described in the section entitled "Saving and restoring compiled
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patterns" below.
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#save <filename>
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This command is used to save a set of compiled patterns to a file, as
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described in the section entitled "Saving and restoring compiled pat-
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terns" below.
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#subject <modifier-list>
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This command sets a default modifier list that applies to all subse-
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quent subject lines. Modifiers on a subject line can change these set-
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tings.
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MODIFIER SYNTAX
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Modifier lists are used with both pattern and subject lines. Items in a
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list are separated by commas followed by optional white space. Trailing
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whitespace in a modifier list is ignored. Some modifiers may be given
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for both patterns and subject lines, whereas others are valid only for
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one or the other. Each modifier has a long name, for example
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"anchored", and some of them must be followed by an equals sign and a
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value, for example, "offset=12". Values cannot contain comma charac-
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ters, but may contain spaces. Modifiers that do not take values may be
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preceded by a minus sign to turn off a previous setting.
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A few of the more common modifiers can also be specified as single let-
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ters, for example "i" for "caseless". In documentation, following the
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Perl convention, these are written with a slash ("the /i modifier") for
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clarity. Abbreviated modifiers must all be concatenated in the first
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item of a modifier list. If the first item is not recognized as a long
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modifier name, it is interpreted as a sequence of these abbreviations.
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For example:
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/abc/ig,newline=cr,jit=3
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This is a pattern line whose modifier list starts with two one-letter
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modifiers (/i and /g). The lower-case abbreviated modifiers are the
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same as used in Perl.
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PATTERN SYNTAX
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A pattern line must start with one of the following characters (common
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symbols, excluding pattern meta-characters):
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/ ! " ' ` - = _ : ; , % & @ ~
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This is interpreted as the pattern's delimiter. A regular expression
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may be continued over several input lines, in which case the newline
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characters are included within it. It is possible to include the delim-
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iter within the pattern by escaping it with a backslash, for example
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/abc\/def/
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If you do this, the escape and the delimiter form part of the pattern,
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but since the delimiters are all non-alphanumeric, this does not affect
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its interpretation. If the terminating delimiter is immediately fol-
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lowed by a backslash, for example,
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/abc/\
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then a backslash is added to the end of the pattern. This is done to
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provide a way of testing the error condition that arises if a pattern
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finishes with a backslash, because
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/abc\/
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is interpreted as the first line of a pattern that starts with "abc/",
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causing pcre2test to read the next line as a continuation of the regu-
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lar expression.
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A pattern can be followed by a modifier list (details below).
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SUBJECT LINE SYNTAX
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Before each subject line is passed to pcre2_match() or
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pcre2_dfa_match(), leading and trailing white space is removed, and the
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line is scanned for backslash escapes. The following provide a means of
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encoding non-printing characters in a visible way:
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\a alarm (BEL, \x07)
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\b backspace (\x08)
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\e escape (\x27)
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\f form feed (\x0c)
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\n newline (\x0a)
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\r carriage return (\x0d)
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\t tab (\x09)
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\v vertical tab (\x0b)
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\nnn octal character (up to 3 octal digits); always
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a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
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\o{dd...} octal character (any number of octal digits}
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\xhh hexadecimal byte (up to 2 hex digits)
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\x{hh...} hexadecimal character (any number of hex digits)
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The use of \x{hh...} is not dependent on the use of the utf modifier on
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the pattern. It is recognized always. There may be any number of hexa-
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decimal digits inside the braces; invalid values provoke error mes-
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sages.
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Note that \xhh specifies one byte rather than one character in UTF-8
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mode; this makes it possible to construct invalid UTF-8 sequences for
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testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
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character in UTF-8 mode, generating more than one byte if the value is
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greater than 127. When testing the 8-bit library not in UTF-8 mode,
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\x{hh} generates one byte for values less than 256, and causes an error
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for greater values.
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In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
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possible to construct invalid UTF-16 sequences for testing purposes.
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In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
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makes it possible to construct invalid UTF-32 sequences for testing
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purposes.
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There is a special backslash sequence that specifies replication of one
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or more characters:
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\[<characters>]{<count>}
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This makes it possible to test long strings without having to provide
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them as part of the file. For example:
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\[abc]{4}
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is converted to "abcabcabcabc". This feature does not support nesting.
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To include a closing square bracket in the characters, code it as \x5D.
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A backslash followed by an equals sign marks the end of the subject
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string and the start of a modifier list. For example:
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abc\=notbol,notempty
|
|
|
|
If the subject string is empty and \= is followed by whitespace, the
|
|
line is treated as a comment line, and is not used for matching. For
|
|
example:
|
|
|
|
\= This is a comment.
|
|
abc\= This is an invalid modifier list.
|
|
|
|
A backslash followed by any other non-alphanumeric character just
|
|
escapes that character. A backslash followed by anything else causes an
|
|
error. However, if the very last character in the line is a backslash
|
|
(and there is no modifier list), it is ignored. This gives a way of
|
|
passing an empty line as data, since a real empty line terminates the
|
|
data input.
|
|
|
|
|
|
PATTERN MODIFIERS
|
|
|
|
There are several types of modifier that can appear in pattern lines.
|
|
Except where noted below, they may also be used in #pattern commands. A
|
|
pattern's modifier list can add to or override default modifiers that
|
|
were set by a previous #pattern command.
|
|
|
|
Setting compilation options
|
|
|
|
The following modifiers set options for pcre2_compile(). The most com-
|
|
mon ones have single-letter abbreviations. See pcre2api for a descrip-
|
|
tion of their effects.
|
|
|
|
allow_empty_class set PCRE2_ALLOW_EMPTY_CLASS
|
|
alt_bsux set PCRE2_ALT_BSUX
|
|
alt_circumflex set PCRE2_ALT_CIRCUMFLEX
|
|
alt_verbnames set PCRE2_ALT_VERBNAMES
|
|
anchored set PCRE2_ANCHORED
|
|
auto_callout set PCRE2_AUTO_CALLOUT
|
|
/i caseless set PCRE2_CASELESS
|
|
dollar_endonly set PCRE2_DOLLAR_ENDONLY
|
|
/s dotall set PCRE2_DOTALL
|
|
dupnames set PCRE2_DUPNAMES
|
|
/x extended set PCRE2_EXTENDED
|
|
firstline set PCRE2_FIRSTLINE
|
|
match_unset_backref set PCRE2_MATCH_UNSET_BACKREF
|
|
/m multiline set PCRE2_MULTILINE
|
|
never_backslash_c set PCRE2_NEVER_BACKSLASH_C
|
|
never_ucp set PCRE2_NEVER_UCP
|
|
never_utf set PCRE2_NEVER_UTF
|
|
no_auto_capture set PCRE2_NO_AUTO_CAPTURE
|
|
no_auto_possess set PCRE2_NO_AUTO_POSSESS
|
|
no_dotstar_anchor set PCRE2_NO_DOTSTAR_ANCHOR
|
|
no_start_optimize set PCRE2_NO_START_OPTIMIZE
|
|
no_utf_check set PCRE2_NO_UTF_CHECK
|
|
ucp set PCRE2_UCP
|
|
ungreedy set PCRE2_UNGREEDY
|
|
use_offset_limit set PCRE2_USE_OFFSET_LIMIT
|
|
utf set PCRE2_UTF
|
|
|
|
As well as turning on the PCRE2_UTF option, the utf modifier causes all
|
|
non-printing characters in output strings to be printed using the
|
|
\x{hh...} notation. Otherwise, those less than 0x100 are output in hex
|
|
without the curly brackets. Setting utf in 16-bit or 32-bit mode also
|
|
causes pattern and subject strings to be translated to UTF-16 or
|
|
UTF-32, respectively, before being passed to library functions.
|
|
|
|
Setting compilation controls
|
|
|
|
The following modifiers affect the compilation process or request
|
|
information about the pattern:
|
|
|
|
bsr=[anycrlf|unicode] specify \R handling
|
|
/B bincode show binary code without lengths
|
|
callout_info show callout information
|
|
debug same as info,fullbincode
|
|
framesize show matching frame size
|
|
fullbincode show binary code with lengths
|
|
/I info show info about compiled pattern
|
|
hex unquoted characters are hexadecimal
|
|
jit[=<number>] use JIT
|
|
jitfast use JIT fast path
|
|
jitverify verify JIT use
|
|
locale=<name> use this locale
|
|
max_pattern_length=<n> set the maximum pattern length
|
|
memory show memory used
|
|
newline=<type> set newline type
|
|
null_context compile with a NULL context
|
|
parens_nest_limit=<n> set maximum parentheses depth
|
|
posix use the POSIX API
|
|
posix_nosub use the POSIX API with REG_NOSUB
|
|
push push compiled pattern onto the stack
|
|
pushcopy push a copy onto the stack
|
|
stackguard=<number> test the stackguard feature
|
|
tables=[0|1|2] select internal tables
|
|
use_length do not zero-terminate the pattern
|
|
utf8_input treat input as UTF-8
|
|
|
|
The effects of these modifiers are described in the following sections.
|
|
|
|
Newline and \R handling
|
|
|
|
The bsr modifier specifies what \R in a pattern should match. If it is
|
|
set to "anycrlf", \R matches CR, LF, or CRLF only. If it is set to
|
|
"unicode", \R matches any Unicode newline sequence. The default is
|
|
specified when PCRE2 is built, with the default default being Unicode.
|
|
|
|
The newline modifier specifies which characters are to be interpreted
|
|
as newlines, both in the pattern and in subject lines. The type must be
|
|
one of CR, LF, CRLF, ANYCRLF, or ANY (in upper or lower case).
|
|
|
|
Information about a pattern
|
|
|
|
The debug modifier is a shorthand for info,fullbincode, requesting all
|
|
available information.
|
|
|
|
The bincode modifier causes a representation of the compiled code to be
|
|
output after compilation. This information does not contain length and
|
|
offset values, which ensures that the same output is generated for dif-
|
|
ferent internal link sizes and different code unit widths. By using
|
|
bincode, the same regression tests can be used in different environ-
|
|
ments.
|
|
|
|
The fullbincode modifier, by contrast, does include length and offset
|
|
values. This is used in a few special tests that run only for specific
|
|
code unit widths and link sizes, and is also useful for one-off tests.
|
|
|
|
The info modifier requests information about the compiled pattern
|
|
(whether it is anchored, has a fixed first character, and so on). The
|
|
information is obtained from the pcre2_pattern_info() function. Here
|
|
are some typical examples:
|
|
|
|
re> /(?i)(^a|^b)/m,info
|
|
Capturing subpattern count = 1
|
|
Compile options: multiline
|
|
Overall options: caseless multiline
|
|
First code unit at start or follows newline
|
|
Subject length lower bound = 1
|
|
|
|
re> /(?i)abc/info
|
|
Capturing subpattern count = 0
|
|
Compile options: <none>
|
|
Overall options: caseless
|
|
First code unit = 'a' (caseless)
|
|
Last code unit = 'c' (caseless)
|
|
Subject length lower bound = 3
|
|
|
|
"Compile options" are those specified by modifiers; "overall options"
|
|
have added options that are taken or deduced from the pattern. If both
|
|
sets of options are the same, just a single "options" line is output;
|
|
if there are no options, the line is omitted. "First code unit" is
|
|
where any match must start; if there is more than one they are listed
|
|
as "starting code units". "Last code unit" is the last literal code
|
|
unit that must be present in any match. This is not necessarily the
|
|
last character. These lines are omitted if no starting or ending code
|
|
units are recorded.
|
|
|
|
The framesize modifier shows the size, in bytes, of the storage frames
|
|
used by pcre2_match() for handling backtracking. The size depends on
|
|
the number of capturing parentheses in the pattern.
|
|
|
|
The callout_info modifier requests information about all the callouts
|
|
in the pattern. A list of them is output at the end of any other infor-
|
|
mation that is requested. For each callout, either its number or string
|
|
is given, followed by the item that follows it in the pattern.
|
|
|
|
Passing a NULL context
|
|
|
|
Normally, pcre2test passes a context block to pcre2_compile(). If the
|
|
null_context modifier is set, however, NULL is passed. This is for
|
|
testing that pcre2_compile() behaves correctly in this case (it uses
|
|
default values).
|
|
|
|
Specifying the pattern's length
|
|
|
|
By default, patterns are passed to the compiling functions as zero-ter-
|
|
minated strings. When using the POSIX wrapper API, there is no other
|
|
option. However, when using PCRE2's native API, patterns can be passed
|
|
by length instead of being zero-terminated. The use_length modifier
|
|
causes this to happen. Using a length happens automatically (whether
|
|
or not use_length is set) when hex is set, because patterns specified
|
|
in hexadecimal may contain binary zeros.
|
|
|
|
Specifying pattern characters in hexadecimal
|
|
|
|
The hex modifier specifies that the characters of the pattern, except
|
|
for substrings enclosed in single or double quotes, are to be inter-
|
|
preted as pairs of hexadecimal digits. This feature is provided as a
|
|
way of creating patterns that contain binary zeros and other non-print-
|
|
ing characters. White space is permitted between pairs of digits. For
|
|
example, this pattern contains three characters:
|
|
|
|
/ab 32 59/hex
|
|
|
|
Parts of such a pattern are taken literally if quoted. This pattern
|
|
contains nine characters, only two of which are specified in hexadeci-
|
|
mal:
|
|
|
|
/ab "literal" 32/hex
|
|
|
|
Either single or double quotes may be used. There is no way of includ-
|
|
ing the delimiter within a substring. The hex and expand modifiers are
|
|
mutually exclusive.
|
|
|
|
The POSIX API cannot be used with patterns specified in hexadecimal
|
|
because they may contain binary zeros, which conflicts with regcomp()'s
|
|
requirement for a zero-terminated string. Such patterns are always
|
|
passed to pcre2_compile() as a string with a length, not as zero-termi-
|
|
nated.
|
|
|
|
Specifying wide characters in 16-bit and 32-bit modes
|
|
|
|
In 16-bit and 32-bit modes, all input is automatically treated as UTF-8
|
|
and translated to UTF-16 or UTF-32 when the utf modifier is set. For
|
|
testing the 16-bit and 32-bit libraries in non-UTF mode, the utf8_input
|
|
modifier can be used. It is mutually exclusive with utf. Input lines
|
|
are interpreted as UTF-8 as a means of specifying wide characters. More
|
|
details are given in "Input encoding" above.
|
|
|
|
Generating long repetitive patterns
|
|
|
|
Some tests use long patterns that are very repetitive. Instead of cre-
|
|
ating a very long input line for such a pattern, you can use a special
|
|
repetition feature, similar to the one described for subject lines
|
|
above. If the expand modifier is present on a pattern, parts of the
|
|
pattern that have the form
|
|
|
|
\[<characters>]{<count>}
|
|
|
|
are expanded before the pattern is passed to pcre2_compile(). For exam-
|
|
ple, \[AB]{6000} is expanded to "ABAB..." 6000 times. This construction
|
|
cannot be nested. An initial "\[" sequence is recognized only if "]{"
|
|
followed by decimal digits and "}" is found later in the pattern. If
|
|
not, the characters remain in the pattern unaltered. The expand and hex
|
|
modifiers are mutually exclusive.
|
|
|
|
If part of an expanded pattern looks like an expansion, but is really
|
|
part of the actual pattern, unwanted expansion can be avoided by giving
|
|
two values in the quantifier. For example, \[AB]{6000,6000} is not rec-
|
|
ognized as an expansion item.
|
|
|
|
If the info modifier is set on an expanded pattern, the result of the
|
|
expansion is included in the information that is output.
|
|
|
|
JIT compilation
|
|
|
|
Just-in-time (JIT) compiling is a heavyweight optimization that can
|
|
greatly speed up pattern matching. See the pcre2jit documentation for
|
|
details. JIT compiling happens, optionally, after a pattern has been
|
|
successfully compiled into an internal form. The JIT compiler converts
|
|
this to optimized machine code. It needs to know whether the match-time
|
|
options PCRE2_PARTIAL_HARD and PCRE2_PARTIAL_SOFT are going to be used,
|
|
because different code is generated for the different cases. See the
|
|
partial modifier in "Subject Modifiers" below for details of how these
|
|
options are specified for each match attempt.
|
|
|
|
JIT compilation is requested by the /jit pattern modifier, which may
|
|
optionally be followed by an equals sign and a number in the range 0 to
|
|
7. The three bits that make up the number specify which of the three
|
|
JIT operating modes are to be compiled:
|
|
|
|
1 compile JIT code for non-partial matching
|
|
2 compile JIT code for soft partial matching
|
|
4 compile JIT code for hard partial matching
|
|
|
|
The possible values for the jit modifier are therefore:
|
|
|
|
0 disable JIT
|
|
1 normal matching only
|
|
2 soft partial matching only
|
|
3 normal and soft partial matching
|
|
4 hard partial matching only
|
|
6 soft and hard partial matching only
|
|
7 all three modes
|
|
|
|
If no number is given, 7 is assumed. The phrase "partial matching"
|
|
means a call to pcre2_match() with either the PCRE2_PARTIAL_SOFT or the
|
|
PCRE2_PARTIAL_HARD option set. Note that such a call may return a com-
|
|
plete match; the options enable the possibility of a partial match, but
|
|
do not require it. Note also that if you request JIT compilation only
|
|
for partial matching (for example, /jit=2) but do not set the partial
|
|
modifier on a subject line, that match will not use JIT code because
|
|
none was compiled for non-partial matching.
|
|
|
|
If JIT compilation is successful, the compiled JIT code will automati-
|
|
cally be used when an appropriate type of match is run, except when
|
|
incompatible run-time options are specified. For more details, see the
|
|
pcre2jit documentation. See also the jitstack modifier below for a way
|
|
of setting the size of the JIT stack.
|
|
|
|
If the jitfast modifier is specified, matching is done using the JIT
|
|
"fast path" interface, pcre2_jit_match(), which skips some of the san-
|
|
ity checks that are done by pcre2_match(), and of course does not work
|
|
when JIT is not supported. If jitfast is specified without jit, jit=7
|
|
is assumed.
|
|
|
|
If the jitverify modifier is specified, information about the compiled
|
|
pattern shows whether JIT compilation was or was not successful. If
|
|
jitverify is specified without jit, jit=7 is assumed. If JIT compila-
|
|
tion is successful when jitverify is set, the text "(JIT)" is added to
|
|
the first output line after a match or non match when JIT-compiled code
|
|
was actually used in the match.
|
|
|
|
Setting a locale
|
|
|
|
The locale modifier must specify the name of a locale, for example:
|
|
|
|
/pattern/locale=fr_FR
|
|
|
|
The given locale is set, pcre2_maketables() is called to build a set of
|
|
character tables for the locale, and this is then passed to pcre2_com-
|
|
pile() when compiling the regular expression. The same tables are used
|
|
when matching the following subject lines. The locale modifier applies
|
|
only to the pattern on which it appears, but can be given in a #pattern
|
|
command if a default is needed. Setting a locale and alternate charac-
|
|
ter tables are mutually exclusive.
|
|
|
|
Showing pattern memory
|
|
|
|
The memory modifier causes the size in bytes of the memory used to hold
|
|
the compiled pattern to be output. This does not include the size of
|
|
the pcre2_code block; it is just the actual compiled data. If the pat-
|
|
tern is subsequently passed to the JIT compiler, the size of the JIT
|
|
compiled code is also output. Here is an example:
|
|
|
|
re> /a(b)c/jit,memory
|
|
Memory allocation (code space): 21
|
|
Memory allocation (JIT code): 1910
|
|
|
|
|
|
Limiting nested parentheses
|
|
|
|
The parens_nest_limit modifier sets a limit on the depth of nested
|
|
parentheses in a pattern. Breaching the limit causes a compilation
|
|
error. The default for the library is set when PCRE2 is built, but
|
|
pcre2test sets its own default of 220, which is required for running
|
|
the standard test suite.
|
|
|
|
Limiting the pattern length
|
|
|
|
The max_pattern_length modifier sets a limit, in code units, to the
|
|
length of pattern that pcre2_compile() will accept. Breaching the limit
|
|
causes a compilation error. The default is the largest number a
|
|
PCRE2_SIZE variable can hold (essentially unlimited).
|
|
|
|
Using the POSIX wrapper API
|
|
|
|
The /posix and posix_nosub modifiers cause pcre2test to call PCRE2 via
|
|
the POSIX wrapper API rather than its native API. When posix_nosub is
|
|
used, the POSIX option REG_NOSUB is passed to regcomp(). The POSIX
|
|
wrapper supports only the 8-bit library. Note that it does not imply
|
|
POSIX matching semantics; for more detail see the pcre2posix documenta-
|
|
tion. The following pattern modifiers set options for the regcomp()
|
|
function:
|
|
|
|
caseless REG_ICASE
|
|
multiline REG_NEWLINE
|
|
dotall REG_DOTALL )
|
|
ungreedy REG_UNGREEDY ) These options are not part of
|
|
ucp REG_UCP ) the POSIX standard
|
|
utf REG_UTF8 )
|
|
|
|
The regerror_buffsize modifier specifies a size for the error buffer
|
|
that is passed to regerror() in the event of a compilation error. For
|
|
example:
|
|
|
|
/abc/posix,regerror_buffsize=20
|
|
|
|
This provides a means of testing the behaviour of regerror() when the
|
|
buffer is too small for the error message. If this modifier has not
|
|
been set, a large buffer is used.
|
|
|
|
The aftertext and allaftertext subject modifiers work as described
|
|
below. All other modifiers are either ignored, with a warning message,
|
|
or cause an error.
|
|
|
|
Testing the stack guard feature
|
|
|
|
The stackguard modifier is used to test the use of pcre2_set_com-
|
|
pile_recursion_guard(), a function that is provided to enable stack
|
|
availability to be checked during compilation (see the pcre2api docu-
|
|
mentation for details). If the number specified by the modifier is
|
|
greater than zero, pcre2_set_compile_recursion_guard() is called to set
|
|
up callback from pcre2_compile() to a local function. The argument it
|
|
receives is the current nesting parenthesis depth; if this is greater
|
|
than the value given by the modifier, non-zero is returned, causing the
|
|
compilation to be aborted.
|
|
|
|
Using alternative character tables
|
|
|
|
The value specified for the tables modifier must be one of the digits
|
|
0, 1, or 2. It causes a specific set of built-in character tables to be
|
|
passed to pcre2_compile(). This is used in the PCRE2 tests to check be-
|
|
haviour with different character tables. The digit specifies the tables
|
|
as follows:
|
|
|
|
0 do not pass any special character tables
|
|
1 the default ASCII tables, as distributed in
|
|
pcre2_chartables.c.dist
|
|
2 a set of tables defining ISO 8859 characters
|
|
|
|
In table 2, some characters whose codes are greater than 128 are iden-
|
|
tified as letters, digits, spaces, etc. Setting alternate character
|
|
tables and a locale are mutually exclusive.
|
|
|
|
Setting certain match controls
|
|
|
|
The following modifiers are really subject modifiers, and are described
|
|
below. However, they may be included in a pattern's modifier list, in
|
|
which case they are applied to every subject line that is processed
|
|
with that pattern. They may not appear in #pattern commands. These mod-
|
|
ifiers do not affect the compilation process.
|
|
|
|
aftertext show text after match
|
|
allaftertext show text after captures
|
|
allcaptures show all captures
|
|
allusedtext show all consulted text
|
|
/g global global matching
|
|
mark show mark values
|
|
replace=<string> specify a replacement string
|
|
startchar show starting character when relevant
|
|
substitute_extended use PCRE2_SUBSTITUTE_EXTENDED
|
|
substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH
|
|
substitute_unknown_unset use PCRE2_SUBSTITUTE_UNKNOWN_UNSET
|
|
substitute_unset_empty use PCRE2_SUBSTITUTE_UNSET_EMPTY
|
|
|
|
These modifiers may not appear in a #pattern command. If you want them
|
|
as defaults, set them in a #subject command.
|
|
|
|
Saving a compiled pattern
|
|
|
|
When a pattern with the push modifier is successfully compiled, it is
|
|
pushed onto a stack of compiled patterns, and pcre2test expects the
|
|
next line to contain a new pattern (or a command) instead of a subject
|
|
line. This facility is used when saving compiled patterns to a file, as
|
|
described in the section entitled "Saving and restoring compiled pat-
|
|
terns" below. If pushcopy is used instead of push, a copy of the com-
|
|
piled pattern is stacked, leaving the original as current, ready to
|
|
match the following input lines. This provides a way of testing the
|
|
pcre2_code_copy() function. The push and pushcopy modifiers are
|
|
incompatible with compilation modifiers such as global that act at
|
|
match time. Any that are specified are ignored (for the stacked copy),
|
|
with a warning message, except for replace, which causes an error. Note
|
|
that jitverify, which is allowed, does not carry through to any subse-
|
|
quent matching that uses a stacked pattern.
|
|
|
|
|
|
SUBJECT MODIFIERS
|
|
|
|
The modifiers that can appear in subject lines and the #subject command
|
|
are of two types.
|
|
|
|
Setting match options
|
|
|
|
The following modifiers set options for pcre2_match() or
|
|
pcre2_dfa_match(). See pcreapi for a description of their effects.
|
|
|
|
anchored set PCRE2_ANCHORED
|
|
dfa_restart set PCRE2_DFA_RESTART
|
|
dfa_shortest set PCRE2_DFA_SHORTEST
|
|
no_jit set PCRE2_NO_JIT
|
|
no_utf_check set PCRE2_NO_UTF_CHECK
|
|
notbol set PCRE2_NOTBOL
|
|
notempty set PCRE2_NOTEMPTY
|
|
notempty_atstart set PCRE2_NOTEMPTY_ATSTART
|
|
noteol set PCRE2_NOTEOL
|
|
partial_hard (or ph) set PCRE2_PARTIAL_HARD
|
|
partial_soft (or ps) set PCRE2_PARTIAL_SOFT
|
|
|
|
The partial matching modifiers are provided with abbreviations because
|
|
they appear frequently in tests.
|
|
|
|
If the posix modifier was present on the pattern, causing the POSIX
|
|
wrapper API to be used, the only option-setting modifiers that have any
|
|
effect are notbol, notempty, and noteol, causing REG_NOTBOL,
|
|
REG_NOTEMPTY, and REG_NOTEOL, respectively, to be passed to regexec().
|
|
The other modifiers are ignored, with a warning message.
|
|
|
|
Setting match controls
|
|
|
|
The following modifiers affect the matching process or request addi-
|
|
tional information. Some of them may also be specified on a pattern
|
|
line (see above), in which case they apply to every subject line that
|
|
is matched against that pattern.
|
|
|
|
aftertext show text after match
|
|
allaftertext show text after captures
|
|
allcaptures show all captures
|
|
allusedtext show all consulted text (non-JIT only)
|
|
altglobal alternative global matching
|
|
callout_capture show captures at callout time
|
|
callout_data=<n> set a value to pass via callouts
|
|
callout_error=<n>[:<m>] control callout error
|
|
callout_fail=<n>[:<m>] control callout failure
|
|
callout_none do not supply a callout function
|
|
copy=<number or name> copy captured substring
|
|
depth_limit=<n> set a depth limit
|
|
dfa use pcre2_dfa_match()
|
|
find_limits find match and recursion limits
|
|
get=<number or name> extract captured substring
|
|
getall extract all captured substrings
|
|
/g global global matching
|
|
jitstack=<n> set size of JIT stack
|
|
mark show mark values
|
|
match_limit=<n> set a match limit
|
|
memory show memory usage
|
|
null_context match with a NULL context
|
|
offset=<n> set starting offset
|
|
offset_limit=<n> set offset limit
|
|
ovector=<n> set size of output vector
|
|
recursion_limit=<n> obsolete synonym for depth_limit
|
|
replace=<string> specify a replacement string
|
|
startchar show startchar when relevant
|
|
startoffset=<n> same as offset=<n>
|
|
substitute_extedded use PCRE2_SUBSTITUTE_EXTENDED
|
|
substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH
|
|
substitute_unknown_unset use PCRE2_SUBSTITUTE_UNKNOWN_UNSET
|
|
substitute_unset_empty use PCRE2_SUBSTITUTE_UNSET_EMPTY
|
|
zero_terminate pass the subject as zero-terminated
|
|
|
|
The effects of these modifiers are described in the following sections.
|
|
When matching via the POSIX wrapper API, the aftertext, allaftertext,
|
|
and ovector subject modifiers work as described below. All other modi-
|
|
fiers are either ignored, with a warning message, or cause an error.
|
|
|
|
Showing more text
|
|
|
|
The aftertext modifier requests that as well as outputting the part of
|
|
the subject string that matched the entire pattern, pcre2test should in
|
|
addition output the remainder of the subject string. This is useful for
|
|
tests where the subject contains multiple copies of the same substring.
|
|
The allaftertext modifier requests the same action for captured sub-
|
|
strings as well as the main matched substring. In each case the remain-
|
|
der is output on the following line with a plus character following the
|
|
capture number.
|
|
|
|
The allusedtext modifier requests that all the text that was consulted
|
|
during a successful pattern match by the interpreter should be shown.
|
|
This feature is not supported for JIT matching, and if requested with
|
|
JIT it is ignored (with a warning message). Setting this modifier
|
|
affects the output if there is a lookbehind at the start of a match, or
|
|
a lookahead at the end, or if \K is used in the pattern. Characters
|
|
that precede or follow the start and end of the actual match are indi-
|
|
cated in the output by '<' or '>' characters underneath them. Here is
|
|
an example:
|
|
|
|
re> /(?<=pqr)abc(?=xyz)/
|
|
data> 123pqrabcxyz456\=allusedtext
|
|
0: pqrabcxyz
|
|
<<< >>>
|
|
|
|
This shows that the matched string is "abc", with the preceding and
|
|
following strings "pqr" and "xyz" having been consulted during the
|
|
match (when processing the assertions).
|
|
|
|
The startchar modifier requests that the starting character for the
|
|
match be indicated, if it is different to the start of the matched
|
|
string. The only time when this occurs is when \K has been processed as
|
|
part of the match. In this situation, the output for the matched string
|
|
is displayed from the starting character instead of from the match
|
|
point, with circumflex characters under the earlier characters. For
|
|
example:
|
|
|
|
re> /abc\Kxyz/
|
|
data> abcxyz\=startchar
|
|
0: abcxyz
|
|
^^^
|
|
|
|
Unlike allusedtext, the startchar modifier can be used with JIT. How-
|
|
ever, these two modifiers are mutually exclusive.
|
|
|
|
Showing the value of all capture groups
|
|
|
|
The allcaptures modifier requests that the values of all potential cap-
|
|
tured parentheses be output after a match. By default, only those up to
|
|
the highest one actually used in the match are output (corresponding to
|
|
the return code from pcre2_match()). Groups that did not take part in
|
|
the match are output as "<unset>". This modifier is not relevant for
|
|
DFA matching (which does no capturing); it is ignored, with a warning
|
|
message, if present.
|
|
|
|
Testing callouts
|
|
|
|
A callout function is supplied when pcre2test calls the library match-
|
|
ing functions, unless callout_none is specified. If callout_capture is
|
|
set, the current captured groups are output when a callout occurs. The
|
|
default return from the callout function is zero, which allows matching
|
|
to continue.
|
|
|
|
The callout_fail modifier can be given one or two numbers. If there is
|
|
only one number, 1 is returned instead of 0 (causing matching to back-
|
|
track) when a callout of that number is reached. If two numbers
|
|
(<n>:<m>) are given, 1 is returned when callout <n> is reached and
|
|
there have been at least <m> callouts. The callout_error modifier is
|
|
similar, except that PCRE2_ERROR_CALLOUT is returned, causing the
|
|
entire matching process to be aborted. If both these modifiers are set
|
|
for the same callout number, callout_error takes precedence.
|
|
|
|
Note that callouts with string arguments are always given the number
|
|
zero. See "Callouts" below for a description of the output when a call-
|
|
out it taken.
|
|
|
|
The callout_data modifier can be given an unsigned or a negative num-
|
|
ber. This is set as the "user data" that is passed to the matching
|
|
function, and passed back when the callout function is invoked. Any
|
|
value other than zero is used as a return from pcre2test's callout
|
|
function.
|
|
|
|
Finding all matches in a string
|
|
|
|
Searching for all possible matches within a subject can be requested by
|
|
the global or altglobal modifier. After finding a match, the matching
|
|
function is called again to search the remainder of the subject. The
|
|
difference between global and altglobal is that the former uses the
|
|
start_offset argument to pcre2_match() or pcre2_dfa_match() to start
|
|
searching at a new point within the entire string (which is what Perl
|
|
does), whereas the latter passes over a shortened subject. This makes a
|
|
difference to the matching process if the pattern begins with a lookbe-
|
|
hind assertion (including \b or \B).
|
|
|
|
If an empty string is matched, the next match is done with the
|
|
PCRE2_NOTEMPTY_ATSTART and PCRE2_ANCHORED flags set, in order to search
|
|
for another, non-empty, match at the same point in the subject. If this
|
|
match fails, the start offset is advanced, and the normal match is
|
|
retried. This imitates the way Perl handles such cases when using the
|
|
/g modifier or the split() function. Normally, the start offset is
|
|
advanced by one character, but if the newline convention recognizes
|
|
CRLF as a newline, and the current character is CR followed by LF, an
|
|
advance of two characters occurs.
|
|
|
|
Testing substring extraction functions
|
|
|
|
The copy and get modifiers can be used to test the pcre2_sub-
|
|
string_copy_xxx() and pcre2_substring_get_xxx() functions. They can be
|
|
given more than once, and each can specify a group name or number, for
|
|
example:
|
|
|
|
abcd\=copy=1,copy=3,get=G1
|
|
|
|
If the #subject command is used to set default copy and/or get lists,
|
|
these can be unset by specifying a negative number to cancel all num-
|
|
bered groups and an empty name to cancel all named groups.
|
|
|
|
The getall modifier tests pcre2_substring_list_get(), which extracts
|
|
all captured substrings.
|
|
|
|
If the subject line is successfully matched, the substrings extracted
|
|
by the convenience functions are output with C, G, or L after the
|
|
string number instead of a colon. This is in addition to the normal
|
|
full list. The string length (that is, the return from the extraction
|
|
function) is given in parentheses after each substring, followed by the
|
|
name when the extraction was by name.
|
|
|
|
Testing the substitution function
|
|
|
|
If the replace modifier is set, the pcre2_substitute() function is
|
|
called instead of one of the matching functions. Note that replacement
|
|
strings cannot contain commas, because a comma signifies the end of a
|
|
modifier. This is not thought to be an issue in a test program.
|
|
|
|
Unlike subject strings, pcre2test does not process replacement strings
|
|
for escape sequences. In UTF mode, a replacement string is checked to
|
|
see if it is a valid UTF-8 string. If so, it is correctly converted to
|
|
a UTF string of the appropriate code unit width. If it is not a valid
|
|
UTF-8 string, the individual code units are copied directly. This pro-
|
|
vides a means of passing an invalid UTF-8 string for testing purposes.
|
|
|
|
The following modifiers set options (in additional to the normal match
|
|
options) for pcre2_substitute():
|
|
|
|
global PCRE2_SUBSTITUTE_GLOBAL
|
|
substitute_extended PCRE2_SUBSTITUTE_EXTENDED
|
|
substitute_overflow_length PCRE2_SUBSTITUTE_OVERFLOW_LENGTH
|
|
substitute_unknown_unset PCRE2_SUBSTITUTE_UNKNOWN_UNSET
|
|
substitute_unset_empty PCRE2_SUBSTITUTE_UNSET_EMPTY
|
|
|
|
|
|
After a successful substitution, the modified string is output, pre-
|
|
ceded by the number of replacements. This may be zero if there were no
|
|
matches. Here is a simple example of a substitution test:
|
|
|
|
/abc/replace=xxx
|
|
=abc=abc=
|
|
1: =xxx=abc=
|
|
=abc=abc=\=global
|
|
2: =xxx=xxx=
|
|
|
|
Subject and replacement strings should be kept relatively short (fewer
|
|
than 256 characters) for substitution tests, as fixed-size buffers are
|
|
used. To make it easy to test for buffer overflow, if the replacement
|
|
string starts with a number in square brackets, that number is passed
|
|
to pcre2_substitute() as the size of the output buffer, with the
|
|
replacement string starting at the next character. Here is an example
|
|
that tests the edge case:
|
|
|
|
/abc/
|
|
123abc123\=replace=[10]XYZ
|
|
1: 123XYZ123
|
|
123abc123\=replace=[9]XYZ
|
|
Failed: error -47: no more memory
|
|
|
|
The default action of pcre2_substitute() is to return
|
|
PCRE2_ERROR_NOMEMORY when the output buffer is too small. However, if
|
|
the PCRE2_SUBSTITUTE_OVERFLOW_LENGTH option is set (by using the sub-
|
|
stitute_overflow_length modifier), pcre2_substitute() continues to go
|
|
through the motions of matching and substituting, in order to compute
|
|
the size of buffer that is required. When this happens, pcre2test shows
|
|
the required buffer length (which includes space for the trailing zero)
|
|
as part of the error message. For example:
|
|
|
|
/abc/substitute_overflow_length
|
|
123abc123\=replace=[9]XYZ
|
|
Failed: error -47: no more memory: 10 code units are needed
|
|
|
|
A replacement string is ignored with POSIX and DFA matching. Specifying
|
|
partial matching provokes an error return ("bad option value") from
|
|
pcre2_substitute().
|
|
|
|
Setting the JIT stack size
|
|
|
|
The jitstack modifier provides a way of setting the maximum stack size
|
|
that is used by the just-in-time optimization code. It is ignored if
|
|
JIT optimization is not being used. The value is a number of kilobytes.
|
|
Providing a stack that is larger than the default 32K is necessary only
|
|
for very complicated patterns.
|
|
|
|
Setting match and depth limits
|
|
|
|
The match_limit and depth_limit modifiers set the appropriate limits in
|
|
the match context. These values are ignored when the find_limits modi-
|
|
fier is specified.
|
|
|
|
Finding minimum limits
|
|
|
|
If the find_limits modifier is present, pcre2test calls pcre2_match()
|
|
several times, setting different values in the match context via
|
|
pcre2_set_match_limit() and pcre2_set_depth_limit() until it finds the
|
|
minimum values for each parameter that allow pcre2_match() to complete
|
|
without error.
|
|
|
|
If JIT is being used, only the match limit is relevant. If DFA matching
|
|
is being used, only the depth limit is relevant, but at present this
|
|
modifier is ignored (with a warning message).
|
|
|
|
The match_limit number is a measure of the amount of backtracking that
|
|
takes place, and learning the minimum value can be instructive. For
|
|
most simple matches, the number is quite small, but for patterns with
|
|
very large numbers of matching possibilities, it can become large very
|
|
quickly with increasing length of subject string. The depth_limit num-
|
|
ber is a measure of how much memory for recording backtracking points
|
|
is needed to complete the match attempt.
|
|
|
|
Showing MARK names
|
|
|
|
|
|
The mark modifier causes the names from backtracking control verbs that
|
|
are returned from calls to pcre2_match() to be displayed. If a mark is
|
|
returned for a match, non-match, or partial match, pcre2test shows it.
|
|
For a match, it is on a line by itself, tagged with "MK:". Otherwise,
|
|
it is added to the non-match message.
|
|
|
|
Showing memory usage
|
|
|
|
The memory modifier causes pcre2test to log all memory allocation and
|
|
freeing calls that occur during a match operation.
|
|
|
|
Setting a starting offset
|
|
|
|
The offset modifier sets an offset in the subject string at which
|
|
matching starts. Its value is a number of code units, not characters.
|
|
|
|
Setting an offset limit
|
|
|
|
The offset_limit modifier sets a limit for unanchored matches. If a
|
|
match cannot be found starting at or before this offset in the subject,
|
|
a "no match" return is given. The data value is a number of code units,
|
|
not characters. When this modifier is used, the use_offset_limit modi-
|
|
fier must have been set for the pattern; if not, an error is generated.
|
|
|
|
Setting the size of the output vector
|
|
|
|
The ovector modifier applies only to the subject line in which it
|
|
appears, though of course it can also be used to set a default in a
|
|
#subject command. It specifies the number of pairs of offsets that are
|
|
available for storing matching information. The default is 15.
|
|
|
|
A value of zero is useful when testing the POSIX API because it causes
|
|
regexec() to be called with a NULL capture vector. When not testing the
|
|
POSIX API, a value of zero is used to cause pcre2_match_data_cre-
|
|
ate_from_pattern() to be called, in order to create a match block of
|
|
exactly the right size for the pattern. (It is not possible to create a
|
|
match block with a zero-length ovector; there is always at least one
|
|
pair of offsets.)
|
|
|
|
Passing the subject as zero-terminated
|
|
|
|
By default, the subject string is passed to a native API matching func-
|
|
tion with its correct length. In order to test the facility for passing
|
|
a zero-terminated string, the zero_terminate modifier is provided. It
|
|
causes the length to be passed as PCRE2_ZERO_TERMINATED. (When matching
|
|
via the POSIX interface, this modifier has no effect, as there is no
|
|
facility for passing a length.)
|
|
|
|
When testing pcre2_substitute(), this modifier also has the effect of
|
|
passing the replacement string as zero-terminated.
|
|
|
|
Passing a NULL context
|
|
|
|
Normally, pcre2test passes a context block to pcre2_match(),
|
|
pcre2_dfa_match() or pcre2_jit_match(). If the null_context modifier is
|
|
set, however, NULL is passed. This is for testing that the matching
|
|
functions behave correctly in this case (they use default values). This
|
|
modifier cannot be used with the find_limits modifier or when testing
|
|
the substitution function.
|
|
|
|
|
|
THE ALTERNATIVE MATCHING FUNCTION
|
|
|
|
By default, pcre2test uses the standard PCRE2 matching function,
|
|
pcre2_match() to match each subject line. PCRE2 also supports an alter-
|
|
native matching function, pcre2_dfa_match(), which operates in a dif-
|
|
ferent way, and has some restrictions. The differences between the two
|
|
functions are described in the pcre2matching documentation.
|
|
|
|
If the dfa modifier is set, the alternative matching function is used.
|
|
This function finds all possible matches at a given point in the sub-
|
|
ject. If, however, the dfa_shortest modifier is set, processing stops
|
|
after the first match is found. This is always the shortest possible
|
|
match.
|
|
|
|
|
|
DEFAULT OUTPUT FROM pcre2test
|
|
|
|
This section describes the output when the normal matching function,
|
|
pcre2_match(), is being used.
|
|
|
|
When a match succeeds, pcre2test outputs the list of captured sub-
|
|
strings, starting with number 0 for the string that matched the whole
|
|
pattern. Otherwise, it outputs "No match" when the return is
|
|
PCRE2_ERROR_NOMATCH, or "Partial match:" followed by the partially
|
|
matching substring when the return is PCRE2_ERROR_PARTIAL. (Note that
|
|
this is the entire substring that was inspected during the partial
|
|
match; it may include characters before the actual match start if a
|
|
lookbehind assertion, \K, \b, or \B was involved.)
|
|
|
|
For any other return, pcre2test outputs the PCRE2 negative error number
|
|
and a short descriptive phrase. If the error is a failed UTF string
|
|
check, the code unit offset of the start of the failing character is
|
|
also output. Here is an example of an interactive pcre2test run.
|
|
|
|
$ pcre2test
|
|
PCRE2 version 10.22 2016-07-29
|
|
|
|
re> /^abc(\d+)/
|
|
data> abc123
|
|
0: abc123
|
|
1: 123
|
|
data> xyz
|
|
No match
|
|
|
|
Unset capturing substrings that are not followed by one that is set are
|
|
not shown by pcre2test unless the allcaptures modifier is specified. In
|
|
the following example, there are two capturing substrings, but when the
|
|
first data line is matched, the second, unset substring is not shown.
|
|
An "internal" unset substring is shown as "<unset>", as for the second
|
|
data line.
|
|
|
|
re> /(a)|(b)/
|
|
data> a
|
|
0: a
|
|
1: a
|
|
data> b
|
|
0: b
|
|
1: <unset>
|
|
2: b
|
|
|
|
If the strings contain any non-printing characters, they are output as
|
|
\xhh escapes if the value is less than 256 and UTF mode is not set.
|
|
Otherwise they are output as \x{hh...} escapes. See below for the defi-
|
|
nition of non-printing characters. If the aftertext modifier is set,
|
|
the output for substring 0 is followed by the the rest of the subject
|
|
string, identified by "0+" like this:
|
|
|
|
re> /cat/aftertext
|
|
data> cataract
|
|
0: cat
|
|
0+ aract
|
|
|
|
If global matching is requested, the results of successive matching
|
|
attempts are output in sequence, like this:
|
|
|
|
re> /\Bi(\w\w)/g
|
|
data> Mississippi
|
|
0: iss
|
|
1: ss
|
|
0: iss
|
|
1: ss
|
|
0: ipp
|
|
1: pp
|
|
|
|
"No match" is output only if the first match attempt fails. Here is an
|
|
example of a failure message (the offset 4 that is specified by the
|
|
offset modifier is past the end of the subject string):
|
|
|
|
re> /xyz/
|
|
data> xyz\=offset=4
|
|
Error -24 (bad offset value)
|
|
|
|
Note that whereas patterns can be continued over several lines (a plain
|
|
">" prompt is used for continuations), subject lines may not. However
|
|
newlines can be included in a subject by means of the \n escape (or \r,
|
|
\r\n, etc., depending on the newline sequence setting).
|
|
|
|
|
|
OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
|
|
|
|
When the alternative matching function, pcre2_dfa_match(), is used, the
|
|
output consists of a list of all the matches that start at the first
|
|
point in the subject where there is at least one match. For example:
|
|
|
|
re> /(tang|tangerine|tan)/
|
|
data> yellow tangerine\=dfa
|
|
0: tangerine
|
|
1: tang
|
|
2: tan
|
|
|
|
Using the normal matching function on this data finds only "tang". The
|
|
longest matching string is always given first (and numbered zero).
|
|
After a PCRE2_ERROR_PARTIAL return, the output is "Partial match:",
|
|
followed by the partially matching substring. Note that this is the
|
|
entire substring that was inspected during the partial match; it may
|
|
include characters before the actual match start if a lookbehind asser-
|
|
tion, \b, or \B was involved. (\K is not supported for DFA matching.)
|
|
|
|
If global matching is requested, the search for further matches resumes
|
|
at the end of the longest match. For example:
|
|
|
|
re> /(tang|tangerine|tan)/g
|
|
data> yellow tangerine and tangy sultana\=dfa
|
|
0: tangerine
|
|
1: tang
|
|
2: tan
|
|
0: tang
|
|
1: tan
|
|
0: tan
|
|
|
|
The alternative matching function does not support substring capture,
|
|
so the modifiers that are concerned with captured substrings are not
|
|
relevant.
|
|
|
|
|
|
RESTARTING AFTER A PARTIAL MATCH
|
|
|
|
When the alternative matching function has given the PCRE2_ERROR_PAR-
|
|
TIAL return, indicating that the subject partially matched the pattern,
|
|
you can restart the match with additional subject data by means of the
|
|
dfa_restart modifier. For example:
|
|
|
|
re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
|
|
data> 23ja\=P,dfa
|
|
Partial match: 23ja
|
|
data> n05\=dfa,dfa_restart
|
|
0: n05
|
|
|
|
For further information about partial matching, see the pcre2partial
|
|
documentation.
|
|
|
|
|
|
CALLOUTS
|
|
|
|
If the pattern contains any callout requests, pcre2test's callout func-
|
|
tion is called during matching unless callout_none is specified. This
|
|
works with both matching functions.
|
|
|
|
The callout function in pcre2test returns zero (carry on matching) by
|
|
default, but you can use a callout_fail modifier in a subject line (as
|
|
described above) to change this and other parameters of the callout.
|
|
|
|
Inserting callouts can be helpful when using pcre2test to check compli-
|
|
cated regular expressions. For further information about callouts, see
|
|
the pcre2callout documentation.
|
|
|
|
The output for callouts with numerical arguments and those with string
|
|
arguments is slightly different.
|
|
|
|
Callouts with numerical arguments
|
|
|
|
By default, the callout function displays the callout number, the start
|
|
and current positions in the subject text at the callout time, and the
|
|
next pattern item to be tested. For example:
|
|
|
|
--->pqrabcdef
|
|
0 ^ ^ \d
|
|
|
|
This output indicates that callout number 0 occurred for a match
|
|
attempt starting at the fourth character of the subject string, when
|
|
the pointer was at the seventh character, and when the next pattern
|
|
item was \d. Just one circumflex is output if the start and current
|
|
positions are the same, or if the current position precedes the start
|
|
position, which can happen if the callout is in a lookbehind assertion.
|
|
|
|
Callouts numbered 255 are assumed to be automatic callouts, inserted as
|
|
a result of the /auto_callout pattern modifier. In this case, instead
|
|
of showing the callout number, the offset in the pattern, preceded by a
|
|
plus, is output. For example:
|
|
|
|
re> /\d?[A-E]\*/auto_callout
|
|
data> E*
|
|
--->E*
|
|
+0 ^ \d?
|
|
+3 ^ [A-E]
|
|
+8 ^^ \*
|
|
+10 ^ ^
|
|
0: E*
|
|
|
|
If a pattern contains (*MARK) items, an additional line is output when-
|
|
ever a change of latest mark is passed to the callout function. For
|
|
example:
|
|
|
|
re> /a(*MARK:X)bc/auto_callout
|
|
data> abc
|
|
--->abc
|
|
+0 ^ a
|
|
+1 ^^ (*MARK:X)
|
|
+10 ^^ b
|
|
Latest Mark: X
|
|
+11 ^ ^ c
|
|
+12 ^ ^
|
|
0: abc
|
|
|
|
The mark changes between matching "a" and "b", but stays the same for
|
|
the rest of the match, so nothing more is output. If, as a result of
|
|
backtracking, the mark reverts to being unset, the text "<unset>" is
|
|
output.
|
|
|
|
Callouts with string arguments
|
|
|
|
The output for a callout with a string argument is similar, except that
|
|
instead of outputting a callout number before the position indicators,
|
|
the callout string and its offset in the pattern string are output
|
|
before the reflection of the subject string, and the subject string is
|
|
reflected for each callout. For example:
|
|
|
|
re> /^ab(?C'first')cd(?C"second")ef/
|
|
data> abcdefg
|
|
Callout (7): 'first'
|
|
--->abcdefg
|
|
^ ^ c
|
|
Callout (20): "second"
|
|
--->abcdefg
|
|
^ ^ e
|
|
0: abcdef
|
|
|
|
|
|
NON-PRINTING CHARACTERS
|
|
|
|
When pcre2test is outputting text in the compiled version of a pattern,
|
|
bytes other than 32-126 are always treated as non-printing characters
|
|
and are therefore shown as hex escapes.
|
|
|
|
When pcre2test is outputting text that is a matched part of a subject
|
|
string, it behaves in the same way, unless a different locale has been
|
|
set for the pattern (using the locale modifier). In this case, the
|
|
isprint() function is used to distinguish printing and non-printing
|
|
characters.
|
|
|
|
|
|
SAVING AND RESTORING COMPILED PATTERNS
|
|
|
|
It is possible to save compiled patterns on disc or elsewhere, and
|
|
reload them later, subject to a number of restrictions. JIT data cannot
|
|
be saved. The host on which the patterns are reloaded must be running
|
|
the same version of PCRE2, with the same code unit width, and must also
|
|
have the same endianness, pointer width and PCRE2_SIZE type. Before
|
|
compiled patterns can be saved they must be serialized, that is, con-
|
|
verted to a stream of bytes. A single byte stream may contain any num-
|
|
ber of compiled patterns, but they must all use the same character
|
|
tables. A single copy of the tables is included in the byte stream (its
|
|
size is 1088 bytes).
|
|
|
|
The functions whose names begin with pcre2_serialize_ are used for
|
|
serializing and de-serializing. They are described in the pcre2serial-
|
|
ize documentation. In this section we describe the features of
|
|
pcre2test that can be used to test these functions.
|
|
|
|
When a pattern with push modifier is successfully compiled, it is
|
|
pushed onto a stack of compiled patterns, and pcre2test expects the
|
|
next line to contain a new pattern (or command) instead of a subject
|
|
line. By contrast, the pushcopy modifier causes a copy of the compiled
|
|
pattern to be stacked, leaving the original available for immediate
|
|
matching. By using push and/or pushcopy, a number of patterns can be
|
|
compiled and retained. These modifiers are incompatible with posix, and
|
|
control modifiers that act at match time are ignored (with a message)
|
|
for the stacked patterns. The jitverify modifier applies only at com-
|
|
pile time.
|
|
|
|
The command
|
|
|
|
#save <filename>
|
|
|
|
causes all the stacked patterns to be serialized and the result written
|
|
to the named file. Afterwards, all the stacked patterns are freed. The
|
|
command
|
|
|
|
#load <filename>
|
|
|
|
reads the data in the file, and then arranges for it to be de-serial-
|
|
ized, with the resulting compiled patterns added to the pattern stack.
|
|
The pattern on the top of the stack can be retrieved by the #pop com-
|
|
mand, which must be followed by lines of subjects that are to be
|
|
matched with the pattern, terminated as usual by an empty line or end
|
|
of file. This command may be followed by a modifier list containing
|
|
only control modifiers that act after a pattern has been compiled. In
|
|
particular, hex, posix, posix_nosub, push, and pushcopy are not
|
|
allowed, nor are any option-setting modifiers. The JIT modifiers are,
|
|
however permitted. Here is an example that saves and reloads two pat-
|
|
terns.
|
|
|
|
/abc/push
|
|
/xyz/push
|
|
#save tempfile
|
|
#load tempfile
|
|
#pop info
|
|
xyz
|
|
|
|
#pop jit,bincode
|
|
abc
|
|
|
|
If jitverify is used with #pop, it does not automatically imply jit,
|
|
which is different behaviour from when it is used on a pattern.
|
|
|
|
The #popcopy command is analagous to the pushcopy modifier in that it
|
|
makes current a copy of the topmost stack pattern, leaving the original
|
|
still on the stack.
|
|
|
|
|
|
SEE ALSO
|
|
|
|
pcre2(3), pcre2api(3), pcre2callout(3), pcre2jit, pcre2matching(3),
|
|
pcre2partial(d), pcre2pattern(3), pcre2serialize(3).
|
|
|
|
|
|
AUTHOR
|
|
|
|
Philip Hazel
|
|
University Computing Service
|
|
Cambridge, England.
|
|
|
|
|
|
REVISION
|
|
|
|
Last updated: 21 March 2017
|
|
Copyright (c) 1997-2017 University of Cambridge.
|