1013 lines
49 KiB
Plaintext
1013 lines
49 KiB
Plaintext
PCRETEST(1) PCRETEST(1)
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NAME
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pcretest - a program for testing Perl-compatible regular expressions.
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SYNOPSIS
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pcretest [options] [input file [output file]]
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pcretest was written as a test program for the PCRE regular expression
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library itself, but it can also be used for experimenting with regular
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expressions. This document describes the features of the test program;
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for details of the regular expressions themselves, see the pcrepattern
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documentation. For details of the PCRE library function calls and their
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options, see the pcreapi , pcre16 and pcre32 documentation.
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The input for pcretest is a sequence of regular expression patterns and
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strings to be matched, as described below. The output shows the result
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of each match. Options on the command line and the patterns control
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PCRE options and exactly what is output.
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As PCRE has evolved, it has acquired many different features, and as a
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result, pcretest now has rather a lot of obscure options for testing
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every possible feature. Some of these options are specifically designed
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for use in conjunction with the test script and data files that are
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distributed as part of PCRE, and are unlikely to be of use otherwise.
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They are all documented here, but without much justification.
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PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
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From release 8.30, two separate PCRE libraries can be built. The origi-
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nal one supports 8-bit character strings, whereas the newer 16-bit
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library supports character strings encoded in 16-bit units. From
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release 8.32, a third library can be built, supporting character
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strings encoded in 32-bit units. The pcretest program can be used to
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test all three libraries. However, it is itself still an 8-bit program,
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reading 8-bit input and writing 8-bit output. When testing the 16-bit
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or 32-bit library, the patterns and data strings are converted to 16-
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or 32-bit format before being passed to the PCRE library functions.
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Results are converted to 8-bit for output.
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References to functions and structures of the form pcre[16|32]_xx below
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mean "pcre_xx when using the 8-bit library or pcre16_xx when using the
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16-bit library".
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COMMAND LINE OPTIONS
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-8 If both the 8-bit library has been built, this option causes
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the 8-bit library to be used (which is the default); if the
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8-bit library has not been built, this option causes an
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error.
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-16 If both the 8-bit or the 32-bit, and the 16-bit libraries
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have been built, this option causes the 16-bit library to be
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used. If only the 16-bit library has been built, this is the
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default (so has no effect). If only the 8-bit or the 32-bit
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library has been built, this option causes an error.
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-32 If both the 8-bit or the 16-bit, and the 32-bit libraries
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have been built, this option causes the 32-bit library to be
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used. If only the 32-bit library has been built, this is the
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default (so has no effect). If only the 8-bit or the 16-bit
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library has been built, this option causes an error.
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-b Behave as if each pattern has the /B (show byte code) modi-
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fier; the internal form is output after compilation.
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-C Output the version number of the PCRE library, and all avail-
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able information about the optional features that are
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included, and then exit. All other 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 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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linksize the internal link size (2, 3, or 4)
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newline the default newline setting:
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CR, LF, CRLF, ANYCRLF, or ANY
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The following options output 1 for true or zero for false:
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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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pcre16 the 16-bit library was built
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pcre32 the 32-bit library was built
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pcre8 the 8-bit library was built
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ucp Unicode property support is available
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utf UTF-8 and/or UTF-16 and/or UTF-32 support is
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available
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-d Behave as if each pattern has the /D (debug) modifier; the
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internal form and information about the compiled pattern is
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output after compilation; -d is equivalent to -b -i.
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-dfa Behave as if each data line contains the \D escape sequence;
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this causes the alternative matching function,
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pcre[16|32]_dfa_exec(), to be used instead of the standard
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pcre[16|32]_exec() function (more detail is given below).
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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 /I modifier; information
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about the compiled pattern is given after compilation.
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-M Behave as if each data line contains the \M escape sequence;
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this causes PCRE to discover the minimum MATCH_LIMIT and
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MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
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repeatedly with different limits.
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-m Output the size of each compiled pattern after it has been
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compiled. This is equivalent to adding /M to each regular
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expression. The size is given in bytes for both libraries.
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-o osize Set the number of elements in the output vector that is used
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when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
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be osize. The default value is 45, which is enough for 14
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capturing subexpressions for pcre[16|32]_exec() or 22 differ-
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ent matches for pcre[16|32]_dfa_exec(). The vector size can
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be changed for individual matching calls by including \O in
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the data line (see below).
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-p Behave as if each pattern has the /P modifier; the POSIX
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wrapper API is used to call PCRE. None of the other options
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has any effect when -p is set. This option can be used only
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with the 8-bit library.
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-q Do not output the version number of pcretest 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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-s or -s+ Behave as if each pattern has the /S modifier; in other
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words, force each pattern to be studied. If -s+ is used, all
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the JIT compile options are passed to pcre[16|32]_study(),
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causing just-in-time optimization to be set up if it is
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available, for both full and partial matching. Specific JIT
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compile options can be selected by following -s+ with a digit
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in the range 1 to 7, which selects the JIT compile modes as
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follows:
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1 normal match only
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2 soft partial match only
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3 normal match and soft partial match
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4 hard partial match only
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6 soft and hard partial match
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7 all three modes (default)
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If -s++ is used instead of -s+ (with or without a following
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digit), the text "(JIT)" is added to the first output line
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after a match or no match when JIT-compiled code was actually
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used.
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Note that there are pattern options that can override -s,
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either specifying no studying at all, or suppressing JIT com-
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pilation.
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If the /I or /D option is present on a pattern (requesting
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output about the compiled pattern), information about the
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result of studying is not included when studying is caused
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only by -s and neither -i nor -d is present on the command
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line. This behaviour means that the output from tests that
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are run with and without -s should be identical, except when
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options that output information about the actual running of a
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match are set.
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The -M, -t, and -tm options, which give information about
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resources used, are likely to produce different output with
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and without -s. Output may also differ if the /C option is
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present on an individual pattern. This uses callouts to trace
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the the matching process, and this may be different between
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studied and non-studied patterns. If the pattern contains
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(*MARK) items there may also be differences, for the same
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reason. The -s command line option can be overridden for spe-
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cific patterns that should never be studied (see the /S pat-
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tern modifier below).
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-t Run each compile, study, and match many times with a timer,
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and output resulting time per compile or match (in millisec-
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onds). Do not set -m with -t, because you will then get the
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size output a zillion times, and the timing will be dis-
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torted. You can control the number of iterations that are
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used for timing by following -t with a number (as a separate
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item on the command line). For example, "-t 1000" would iter-
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ate 1000 times. The default is to iterate 500000 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 or study phases.
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DESCRIPTION
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If pcretest is given two filename arguments, it reads from the first
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and writes to the second. If it is given only one filename argument, it
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reads from that file and writes to stdout. Otherwise, it reads from
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stdin and writes to stdout, and prompts for each line of input, using
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"re>" to prompt for regular expressions, and "data>" to prompt for data
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lines.
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When pcretest is built, a configuration option can specify that it
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should be linked with the libreadline library. When this is done, if
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the input is from a terminal, it is read using the readline() function.
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This provides line-editing and history facilities. The output from the
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-help option states whether or not readline() will be used.
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The program handles any number of sets of input on a single input file.
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Each set starts with a regular expression, and continues with any num-
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ber of data lines to be matched against the pattern.
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Each data line is matched separately and independently. If you want to
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do multi-line matches, you have to use the \n escape sequence (or \r or
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\r\n, etc., depending on the newline setting) in a single line of input
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to encode the newline sequences. There is no limit on the length of
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data lines; the input buffer is automatically extended if it is too
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small.
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An empty line signals the end of the data lines, at which point a new
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regular expression is read. The regular expressions are given enclosed
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in any non-alphanumeric delimiters other than backslash, for example:
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/(a|bc)x+yz/
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White space before the initial delimiter is ignored. A regular expres-
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sion may be continued over several input lines, in which case the new-
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line characters are included within it. It is possible to include the
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delimiter within the pattern by escaping it, for example
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/abc\/def/
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If you do so, the escape and the delimiter form part of the pattern,
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but since delimiters are always 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 pcretest to read the next line as a continuation of the regular
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expression.
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PATTERN MODIFIERS
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A pattern may be followed by any number of modifiers, which are mostly
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single characters, though some of these can be qualified by further
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characters. Following Perl usage, these are referred to below as, for
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example, "the /i modifier", even though the delimiter of the pattern
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need not always be a slash, and no slash is used when writing modi-
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fiers. White space may appear between the final pattern delimiter and
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the first modifier, and between the modifiers themselves. For refer-
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ence, here is a complete list of modifiers. They fall into several
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groups that are described in detail in the following sections.
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/8 set UTF mode
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/? disable UTF validity check
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/+ show remainder of subject after match
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/= show all captures (not just those that are set)
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/A set PCRE_ANCHORED
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/B show compiled code
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/C set PCRE_AUTO_CALLOUT
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/D same as /B plus /I
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/E set PCRE_DOLLAR_ENDONLY
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/F flip byte order in compiled pattern
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/f set PCRE_FIRSTLINE
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/G find all matches (shorten string)
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/g find all matches (use startoffset)
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/I show information about pattern
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/i set PCRE_CASELESS
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/J set PCRE_DUPNAMES
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/K show backtracking control names
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/L set locale
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/M show compiled memory size
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/m set PCRE_MULTILINE
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/N set PCRE_NO_AUTO_CAPTURE
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/P use the POSIX wrapper
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/S study the pattern after compilation
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/s set PCRE_DOTALL
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/T select character tables
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/U set PCRE_UNGREEDY
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/W set PCRE_UCP
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/X set PCRE_EXTRA
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/x set PCRE_EXTENDED
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/Y set PCRE_NO_START_OPTIMIZE
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/Z don't show lengths in /B output
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/<any> set PCRE_NEWLINE_ANY
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/<anycrlf> set PCRE_NEWLINE_ANYCRLF
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/<cr> set PCRE_NEWLINE_CR
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/<crlf> set PCRE_NEWLINE_CRLF
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/<lf> set PCRE_NEWLINE_LF
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/<bsr_anycrlf> set PCRE_BSR_ANYCRLF
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/<bsr_unicode> set PCRE_BSR_UNICODE
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/<JS> set PCRE_JAVASCRIPT_COMPAT
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Perl-compatible modifiers
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The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
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PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
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pcre[16|32]_compile() is called. These four modifier letters have the
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same effect as they do in Perl. For example:
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/caseless/i
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Modifiers for other PCRE options
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The following table shows additional modifiers for setting PCRE com-
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pile-time options that do not correspond to anything in Perl:
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/8 PCRE_UTF8 ) when using the 8-bit
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/? PCRE_NO_UTF8_CHECK ) library
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/8 PCRE_UTF16 ) when using the 16-bit
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/? PCRE_NO_UTF16_CHECK ) library
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/8 PCRE_UTF32 ) when using the 32-bit
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/? PCRE_NO_UTF32_CHECK ) library
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/A PCRE_ANCHORED
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/C PCRE_AUTO_CALLOUT
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/E PCRE_DOLLAR_ENDONLY
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/f PCRE_FIRSTLINE
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/J PCRE_DUPNAMES
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/N PCRE_NO_AUTO_CAPTURE
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/U PCRE_UNGREEDY
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/W PCRE_UCP
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/X PCRE_EXTRA
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/Y PCRE_NO_START_OPTIMIZE
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/<any> PCRE_NEWLINE_ANY
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/<anycrlf> PCRE_NEWLINE_ANYCRLF
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/<cr> PCRE_NEWLINE_CR
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/<crlf> PCRE_NEWLINE_CRLF
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/<lf> PCRE_NEWLINE_LF
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/<bsr_anycrlf> PCRE_BSR_ANYCRLF
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/<bsr_unicode> PCRE_BSR_UNICODE
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/<JS> PCRE_JAVASCRIPT_COMPAT
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The modifiers that are enclosed in angle brackets are literal strings
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as shown, including the angle brackets, but the letters within can be
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in either case. This example sets multiline matching with CRLF as the
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line ending sequence:
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/^abc/m<CRLF>
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As well as turning on the PCRE_UTF8/16/32 option, the /8 modifier
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causes all non-printing characters in output strings to be printed
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using the \x{hh...} notation. Otherwise, those less than 0x100 are out-
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put in hex without the curly brackets.
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Full details of the PCRE options are given in the pcreapi documenta-
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tion.
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Finding all matches in a string
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Searching for all possible matches within each subject string can be
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requested by the /g or /G modifier. After finding a match, PCRE is
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called again to search the remainder of the subject string. The differ-
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ence between /g and /G is that the former uses the startoffset argument
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to pcre[16|32]_exec() to start searching at a new point within the
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entire string (which is in effect what Perl does), whereas the latter
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passes over a shortened substring. This makes a difference to the
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matching process if the pattern begins with a lookbehind assertion
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(including \b or \B).
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If any call to pcre[16|32]_exec() in a /g or /G sequence matches an
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empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
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PCRE_ANCHORED flags set in order to search for another, non-empty,
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match at the same point. If this second match fails, the start offset
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is advanced, and the normal match is retried. This imitates the way
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Perl handles such cases when using the /g modifier or the split() func-
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tion. Normally, the start offset is advanced by one character, but if
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the newline convention recognizes CRLF as a newline, and the current
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character is CR followed by LF, an advance of two is used.
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Other modifiers
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There are yet more modifiers for controlling the way pcretest operates.
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The /+ modifier requests that as well as outputting the substring that
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matched the entire pattern, pcretest should in addition output the
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remainder of the subject string. This is useful for tests where the
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subject contains multiple copies of the same substring. If the + modi-
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fier appears twice, the same action is taken for captured substrings.
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In each case the remainder is output on the following line with a plus
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character following the capture number. Note that this modifier must
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not immediately follow the /S modifier because /S+ and /S++ have other
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meanings.
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The /= modifier requests that the values of all potential captured
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parentheses be output after a match. By default, only those up to the
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highest one actually used in the match are output (corresponding to the
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return code from pcre[16|32]_exec()). Values in the offsets vector cor-
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responding to higher numbers should be set to -1, and these are output
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as "<unset>". This modifier gives a way of checking that this is hap-
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pening.
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The /B modifier is a debugging feature. It requests that pcretest out-
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put a representation of the compiled code after compilation. Normally
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this information contains length and offset values; however, if /Z is
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also present, this data is replaced by spaces. This is a special fea-
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ture for use in the automatic test scripts; it ensures that the same
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output is generated for different internal link sizes.
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The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
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that is, both the /B and the /I modifiers.
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The /F modifier causes pcretest to flip the byte order of the 2-byte
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and 4-byte fields in the compiled pattern. This facility is for testing
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the feature in PCRE that allows it to execute patterns that were com-
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piled on a host with a different endianness. This feature is not avail-
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able when the POSIX interface to PCRE is being used, that is, when the
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/P pattern modifier is specified. See also the section about saving and
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reloading compiled patterns below.
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The /I modifier requests that pcretest output information about the
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compiled pattern (whether it is anchored, has a fixed first character,
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and so on). It does this by calling pcre[16|32]_fullinfo() after com-
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piling a pattern. If the pattern is studied, the results of that are
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also output.
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The /K modifier requests pcretest to show names from backtracking con-
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trol verbs that are returned from calls to pcre[16|32]_exec(). It
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causes pcretest to create a pcre[16|32]_extra block if one has not
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already been created by a call to pcre[16|32]_study(), and to set the
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PCRE_EXTRA_MARK flag and the mark field within it, every time that
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pcre[16|32]_exec() is called. If the variable that the mark field
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points to is non-NULL for a match, non-match, or partial match,
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pcretest prints the string to which it points. For a match, this is
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shown on a line by itself, tagged with "MK:". For a non-match it is
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added to the message.
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The /L modifier must be followed directly by the name of a locale, for
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example,
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/pattern/Lfr_FR
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For this reason, it must be the last modifier. The given locale is set,
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pcre[16|32]_maketables() is called to build a set of character tables
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for the locale, and this is then passed to pcre[16|32]_compile() when
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compiling the regular expression. Without an /L (or /T) modifier, NULL
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is passed as the tables pointer; that is, /L applies only to the
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expression on which it appears.
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The /M modifier causes the size in bytes of the memory block used to
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hold the compiled pattern to be output. This does not include the size
|
|
of the pcre[16|32] block; it is just the actual compiled data. If the
|
|
pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
|
|
the size of the JIT compiled code is also output.
|
|
|
|
The /S modifier causes pcre[16|32]_study() to be called after the
|
|
expression has been compiled, and the results used when the expression
|
|
is matched. There are a number of qualifying characters that may follow
|
|
/S. They may appear in any order.
|
|
|
|
If S is followed by an exclamation mark, pcre[16|32]_study() is called
|
|
with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
|
|
pcre_extra block, even when studying discovers no useful information.
|
|
|
|
If /S is followed by a second S character, it suppresses studying, even
|
|
if it was requested externally by the -s command line option. This
|
|
makes it possible to specify that certain patterns are always studied,
|
|
and others are never studied, independently of -s. This feature is used
|
|
in the test files in a few cases where the output is different when the
|
|
pattern is studied.
|
|
|
|
If the /S modifier is followed by a + character, the call to
|
|
pcre[16|32]_study() is made with all the JIT study options, requesting
|
|
just-in-time optimization support if it is available, for both normal
|
|
and partial matching. If you want to restrict the JIT compiling modes,
|
|
you can follow /S+ with a digit in the range 1 to 7:
|
|
|
|
1 normal match only
|
|
2 soft partial match only
|
|
3 normal match and soft partial match
|
|
4 hard partial match only
|
|
6 soft and hard partial match
|
|
7 all three modes (default)
|
|
|
|
If /S++ is used instead of /S+ (with or without a following digit), the
|
|
text "(JIT)" is added to the first output line after a match or no
|
|
match when JIT-compiled code was actually used.
|
|
|
|
Note that there is also an independent /+ modifier; it must not be
|
|
given immediately after /S or /S+ because this will be misinterpreted.
|
|
|
|
If JIT studying is successful, the compiled JIT code will automatically
|
|
be used when pcre[16|32]_exec() is run, except when incompatible run-
|
|
time options are specified. For more details, see the pcrejit documen-
|
|
tation. See also the \J escape sequence below for a way of setting the
|
|
size of the JIT stack.
|
|
|
|
Finally, if /S is followed by a minus character, JIT compilation is
|
|
suppressed, even if it was requested externally by the -s command line
|
|
option. This makes it possible to specify that JIT is never to be used
|
|
for certain patterns.
|
|
|
|
The /T modifier must be followed by a single digit. It causes a spe-
|
|
cific set of built-in character tables to be passed to pcre[16|32]_com-
|
|
pile(). It is used in the standard PCRE tests to check behaviour with
|
|
different character tables. The digit specifies the tables as follows:
|
|
|
|
0 the default ASCII tables, as distributed in
|
|
pcre_chartables.c.dist
|
|
1 a set of tables defining ISO 8859 characters
|
|
|
|
In table 1, some characters whose codes are greater than 128 are iden-
|
|
tified as letters, digits, spaces, etc.
|
|
|
|
Using the POSIX wrapper API
|
|
|
|
The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
|
|
rather than its native API. This supports only the 8-bit library. When
|
|
/P is set, the following modifiers set options for the regcomp() func-
|
|
tion:
|
|
|
|
/i REG_ICASE
|
|
/m REG_NEWLINE
|
|
/N REG_NOSUB
|
|
/s REG_DOTALL )
|
|
/U REG_UNGREEDY ) These options are not part of
|
|
/W REG_UCP ) the POSIX standard
|
|
/8 REG_UTF8 )
|
|
|
|
The /+ modifier works as described above. All other modifiers are
|
|
ignored.
|
|
|
|
|
|
DATA LINES
|
|
|
|
Before each data line is passed to pcre[16|32]_exec(), leading and
|
|
trailing white space is removed, and it is then scanned for \ escapes.
|
|
Some of these are pretty esoteric features, intended for checking out
|
|
some of the more complicated features of PCRE. If you are just testing
|
|
"ordinary" regular expressions, you probably don't need any of these.
|
|
The following escapes are recognized:
|
|
|
|
\a alarm (BEL, \x07)
|
|
\b backspace (\x08)
|
|
\e escape (\x27)
|
|
\f form feed (\x0c)
|
|
\n newline (\x0a)
|
|
\qdd set the PCRE_MATCH_LIMIT limit to dd
|
|
(any number of digits)
|
|
\r carriage return (\x0d)
|
|
\t tab (\x09)
|
|
\v vertical tab (\x0b)
|
|
\nnn octal character (up to 3 octal digits); always
|
|
a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
|
|
\xhh hexadecimal byte (up to 2 hex digits)
|
|
\x{hh...} hexadecimal character (any number of hex digits)
|
|
\A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\Cdd call pcre[16|32]_copy_substring() for substring dd
|
|
after a successful match (number less than 32)
|
|
\Cname call pcre[16|32]_copy_named_substring() for substring
|
|
"name" after a successful match (name termin-
|
|
ated by next non alphanumeric character)
|
|
\C+ show the current captured substrings at callout
|
|
time
|
|
\C- do not supply a callout function
|
|
\C!n return 1 instead of 0 when callout number n is
|
|
reached
|
|
\C!n!m return 1 instead of 0 when callout number n is
|
|
reached for the nth time
|
|
\C*n pass the number n (may be negative) as callout
|
|
data; this is used as the callout return value
|
|
\D use the pcre[16|32]_dfa_exec() match function
|
|
\F only shortest match for pcre[16|32]_dfa_exec()
|
|
\Gdd call pcre[16|32]_get_substring() for substring dd
|
|
after a successful match (number less than 32)
|
|
\Gname call pcre[16|32]_get_named_substring() for substring
|
|
"name" after a successful match (name termin-
|
|
ated by next non-alphanumeric character)
|
|
\Jdd set up a JIT stack of dd kilobytes maximum (any
|
|
number of digits)
|
|
\L call pcre[16|32]_get_substringlist() after a
|
|
successful match
|
|
\M discover the minimum MATCH_LIMIT and
|
|
MATCH_LIMIT_RECURSION settings
|
|
\N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec(); if used twice, pass the
|
|
PCRE_NOTEMPTY_ATSTART option
|
|
\Odd set the size of the output vector passed to
|
|
pcre[16|32]_exec() to dd (any number of digits)
|
|
\P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec(); if used twice, pass the
|
|
PCRE_PARTIAL_HARD option
|
|
\Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
|
|
(any number of digits)
|
|
\R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
|
|
\S output details of memory get/free calls during matching
|
|
\Y pass the PCRE_NO_START_OPTIMIZE option to
|
|
pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
|
|
pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
|
|
\>dd start the match at offset dd (optional "-"; then
|
|
any number of digits); this sets the startoffset
|
|
argument for pcre[16|32]_exec() or
|
|
pcre[16|32]_dfa_exec()
|
|
\<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
\<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
|
|
or pcre[16|32]_dfa_exec()
|
|
|
|
The use of \x{hh...} is not dependent on the use of the /8 modifier on
|
|
the pattern. It is recognized always. There may be any number of hexa-
|
|
decimal digits inside the braces; invalid values provoke error mes-
|
|
sages.
|
|
|
|
Note that \xhh specifies one byte rather than one character in UTF-8
|
|
mode; this makes it possible to construct invalid UTF-8 sequences for
|
|
testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
|
|
character in UTF-8 mode, generating more than one byte if the value is
|
|
greater than 127. When testing the 8-bit library not in UTF-8 mode,
|
|
\x{hh} generates one byte for values less than 256, and causes an error
|
|
for greater values.
|
|
|
|
In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
|
|
possible to construct invalid UTF-16 sequences for testing purposes.
|
|
|
|
In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
|
|
makes it possible to construct invalid UTF-32 sequences for testing
|
|
purposes.
|
|
|
|
The escapes that specify line ending sequences are literal strings,
|
|
exactly as shown. No more than one newline setting should be present in
|
|
any data line.
|
|
|
|
A backslash followed by anything else just escapes the anything else.
|
|
If the very last character is a backslash, it is ignored. This gives a
|
|
way of passing an empty line as data, since a real empty line termi-
|
|
nates the data input.
|
|
|
|
The \J escape provides a way of setting the maximum stack size that is
|
|
used by the just-in-time optimization code. It is ignored if JIT opti-
|
|
mization is not being used. Providing a stack that is larger than the
|
|
default 32K is necessary only for very complicated patterns.
|
|
|
|
If \M is present, pcretest calls pcre[16|32]_exec() several times, with
|
|
different values in the match_limit and match_limit_recursion fields of
|
|
the pcre[16|32]_extra data structure, until it finds the minimum num-
|
|
bers for each parameter that allow pcre[16|32]_exec() to complete with-
|
|
out error. Because this is testing a specific feature of the normal
|
|
interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza-
|
|
tion that might have been set up by the /S+ qualifier of -s+ option is
|
|
disabled.
|
|
|
|
The match_limit number is a measure of the amount of backtracking that
|
|
takes place, and checking it out 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 match_limit_recursion
|
|
number is a measure of how much stack (or, if PCRE is compiled with
|
|
NO_RECURSE, how much heap) memory is needed to complete the match
|
|
attempt.
|
|
|
|
When \O is used, the value specified may be higher or lower than the
|
|
size set by the -O command line option (or defaulted to 45); \O applies
|
|
only to the call of pcre[16|32]_exec() for the line in which it
|
|
appears.
|
|
|
|
If the /P modifier was present on the pattern, causing the POSIX wrap-
|
|
per API to be used, the only option-setting sequences that have any
|
|
effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
|
|
REG_NOTEOL, respectively, to be passed to regexec().
|
|
|
|
|
|
THE ALTERNATIVE MATCHING FUNCTION
|
|
|
|
By default, pcretest uses the standard PCRE matching function,
|
|
pcre[16|32]_exec() to match each data line. PCRE also supports an
|
|
alternative matching function, pcre[16|32]_dfa_test(), which operates
|
|
in a different way, and has some restrictions. The differences between
|
|
the two functions are described in the pcrematching documentation.
|
|
|
|
If a data line contains the \D escape sequence, or if the command line
|
|
contains the -dfa option, the alternative matching function is used.
|
|
This function finds all possible matches at a given point. If, however,
|
|
the \F escape sequence is present in the data line, it stops after the
|
|
first match is found. This is always the shortest possible match.
|
|
|
|
|
|
DEFAULT OUTPUT FROM PCRETEST
|
|
|
|
This section describes the output when the normal matching function,
|
|
pcre[16|32]_exec(), is being used.
|
|
|
|
When a match succeeds, pcretest outputs the list of captured substrings
|
|
that pcre[16|32]_exec() returns, starting with number 0 for the string
|
|
that matched the whole pattern. Otherwise, it outputs "No match" when
|
|
the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
|
|
partially matching substring when pcre[16|32]_exec() returns
|
|
PCRE_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, pcretest outputs the PCRE negative
|
|
error number and a short descriptive phrase. If the error is a failed
|
|
UTF string check, the offset of the start of the failing character and
|
|
the reason code are also output, provided that the size of the output
|
|
vector is at least two. Here is an example of an interactive pcretest
|
|
run.
|
|
|
|
$ pcretest
|
|
PCRE version 8.13 2011-04-30
|
|
|
|
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 returned by pcre[16|32]_exec(), and are not shown by pcretest. 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 pattern has the /+ modifier,
|
|
the output for substring 0 is followed by the the rest of the subject
|
|
string, identified by "0+" like this:
|
|
|
|
re> /cat/+
|
|
data> cataract
|
|
0: cat
|
|
0+ aract
|
|
|
|
If the pattern has the /g or /G modifier, 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 \>4 is
|
|
past the end of the subject string):
|
|
|
|
re> /xyz/
|
|
data> xyz\>4
|
|
Error -24 (bad offset value)
|
|
|
|
If any of the sequences \C, \G, or \L are present in a data line that
|
|
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 paren-
|
|
theses after each string for \C and \G.
|
|
|
|
Note that whereas patterns can be continued over several lines (a plain
|
|
">" prompt is used for continuations), data lines may not. However new-
|
|
lines can be included in data 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, pcre[16|32]_dfa_exec(), is used
|
|
(by means of the \D escape sequence or the -dfa command line option),
|
|
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 exam-
|
|
ple:
|
|
|
|
re> /(tang|tangerine|tan)/
|
|
data> yellow tangerine\D
|
|
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 PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
|
|
lowed 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, \K, \b, or \B was involved.)
|
|
|
|
If /g is present on the pattern, 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\D
|
|
0: tangerine
|
|
1: tang
|
|
2: tan
|
|
0: tang
|
|
1: tan
|
|
0: tan
|
|
|
|
Since the matching function does not support substring capture, the
|
|
escape sequences that are concerned with captured substrings are not
|
|
relevant.
|
|
|
|
|
|
RESTARTING AFTER A PARTIAL MATCH
|
|
|
|
When the alternative matching function has given the PCRE_ERROR_PARTIAL
|
|
return, indicating that the subject partially matched the pattern, you
|
|
can restart the match with additional subject data by means of the \R
|
|
escape sequence. For example:
|
|
|
|
re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
|
|
data> 23ja\P\D
|
|
Partial match: 23ja
|
|
data> n05\R\D
|
|
0: n05
|
|
|
|
For further information about partial matching, see the pcrepartial
|
|
documentation.
|
|
|
|
|
|
CALLOUTS
|
|
|
|
If the pattern contains any callout requests, pcretest's callout func-
|
|
tion is called during matching. This works with both matching func-
|
|
tions. By default, the called function displays the callout number, the
|
|
start and current positions in the 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 of the data, and when the next
|
|
pattern item was \d. Just one circumflex is output if the start and
|
|
current positions are the same.
|
|
|
|
Callouts numbered 255 are assumed to be automatic callouts, inserted as
|
|
a result of the /C 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]\*/C
|
|
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/C
|
|
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.
|
|
|
|
The callout function in pcretest returns zero (carry on matching) by
|
|
default, but you can use a \C item in a data line (as described above)
|
|
to change this and other parameters of the callout.
|
|
|
|
Inserting callouts can be helpful when using pcretest to check compli-
|
|
cated regular expressions. For further information about callouts, see
|
|
the pcrecallout documentation.
|
|
|
|
|
|
NON-PRINTING CHARACTERS
|
|
|
|
When pcretest is outputting text in the compiled version of a pattern,
|
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bytes other than 32-126 are always treated as non-printing characters
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are are therefore shown as hex escapes.
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When pcretest is outputting text that is a matched part of a subject
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string, it behaves in the same way, unless a different locale has been
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set for the pattern (using the /L modifier). In this case, the
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isprint() function to distinguish printing and non-printing characters.
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SAVING AND RELOADING COMPILED PATTERNS
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The facilities described in this section are not available when the
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POSIX interface to PCRE is being used, that is, when the /P pattern
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modifier is specified.
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When the POSIX interface is not in use, you can cause pcretest to write
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|
a compiled pattern to a file, by following the modifiers with > and a
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file name. For example:
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/pattern/im >/some/file
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See the pcreprecompile documentation for a discussion about saving and
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|
re-using compiled patterns. Note that if the pattern was successfully
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|
studied with JIT optimization, the JIT data cannot be saved.
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|
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|
The data that is written is binary. The first eight bytes are the
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|
length of the compiled pattern data followed by the length of the
|
|
optional study data, each written as four bytes in big-endian order
|
|
(most significant byte first). If there is no study data (either the
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|
pattern was not studied, or studying did not return any data), the sec-
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|
ond length is zero. The lengths are followed by an exact copy of the
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|
compiled pattern. If there is additional study data, this (excluding
|
|
any JIT data) follows immediately after the compiled pattern. After
|
|
writing the file, pcretest expects to read a new pattern.
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|
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|
A saved pattern can be reloaded into pcretest by specifying < and a
|
|
file name instead of a pattern. The name of the file must not contain a
|
|
< character, as otherwise pcretest will interpret the line as a pattern
|
|
delimited by < characters. For example:
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|
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|
re> </some/file
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|
Compiled pattern loaded from /some/file
|
|
No study data
|
|
|
|
If the pattern was previously studied with the JIT optimization, the
|
|
JIT information cannot be saved and restored, and so is lost. When the
|
|
pattern has been loaded, pcretest proceeds to read data lines in the
|
|
usual way.
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|
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|
You can copy a file written by pcretest to a different host and reload
|
|
it there, even if the new host has opposite endianness to the one on
|
|
which the pattern was compiled. For example, you can compile on an i86
|
|
machine and run on a SPARC machine. When a pattern is reloaded on a
|
|
host with different endianness, the confirmation message is changed to:
|
|
|
|
Compiled pattern (byte-inverted) loaded from /some/file
|
|
|
|
The test suite contains some saved pre-compiled patterns with different
|
|
endianness. These are reloaded using "<!" instead of just "<". This
|
|
suppresses the "(byte-inverted)" text so that the output is the same on
|
|
all hosts. It also forces debugging output once the pattern has been
|
|
reloaded.
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|
|
|
File names for saving and reloading can be absolute or relative, but
|
|
note that the shell facility of expanding a file name that starts with
|
|
a tilde (~) is not available.
|
|
|
|
The ability to save and reload files in pcretest is intended for test-
|
|
ing and experimentation. It is not intended for production use because
|
|
only a single pattern can be written to a file. Furthermore, there is
|
|
no facility for supplying custom character tables for use with a
|
|
reloaded pattern. If the original pattern was compiled with custom
|
|
tables, an attempt to match a subject string using a reloaded pattern
|
|
is likely to cause pcretest to crash. Finally, if you attempt to load
|
|
a file that is not in the correct format, the result is undefined.
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|
|
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|
SEE ALSO
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|
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|
pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
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|
pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
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AUTHOR
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|
Philip Hazel
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University Computing Service
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|
Cambridge CB2 3QH, England.
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REVISION
|
|
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|
Last updated: 10 September 2012
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Copyright (c) 1997-2012 University of Cambridge.
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