1280 lines
50 KiB
Groff
1280 lines
50 KiB
Groff
.TH PCRE2TEST 1 "23 November 2014" "PCRE 10.00"
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.SH NAME
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pcre2test - a program for testing Perl-compatible regular expressions.
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.SH SYNOPSIS
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.rs
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.sp
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.B pcre2test "[options] [input file [output file]]"
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.sp
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\fBpcre2test\fP 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. This
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document describes the features of the test program; for details of the regular
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expressions themselves, see the
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.\" HREF
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\fBpcre2pattern\fP
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.\"
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documentation. For details of the PCRE2 library function calls and their
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options, see the
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.\" HREF
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\fBpcre2api\fP
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.\"
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documentation.
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.P
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The input for \fBpcre2test\fP is a sequence of regular expression patterns and
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subject strings to be matched. The output shows the result of each match
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attempt. Modifiers on the command line, the patterns, and the subject lines
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specify PCRE2 function options, control how the subject is processed, and what
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output is produced.
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.P
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As the original fairly simple PCRE library evolved, it acquired many different
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features, and as a result, the original \fBpcretest\fP program ended up with a
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lot of options in a messy, arcane syntax, for testing all the features. The
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move to the new PCRE2 API provided an opportunity to re-implement the test
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program as \fBpcre2test\fP, with a cleaner modifier syntax. Nevertheless, there
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are still many obscure modifiers, some of which are specifically designed for
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use in conjunction with the test script and data files that are distributed as
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part of PCRE2. All the modifiers are documented here, some without much
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justification, but many of them are unlikely to be of use except when testing
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the libraries.
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.
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.
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.SH "PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES"
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.rs
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.sp
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Different versions of the PCRE2 library can be built to support character
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strings that are encoded in 8-bit, 16-bit, or 32-bit code units. One, two, or
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all three of these libraries may be simultaneously installed. The
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\fBpcre2test\fP program can be used to test all the libraries. However, its own
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input and output are always in 8-bit format. When testing the 16-bit or 32-bit
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libraries, patterns and subject strings are converted to 16- or 32-bit format
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before being passed to the library functions. Results are converted back to
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8-bit code units for output.
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.P
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In the rest of this document, the names of library functions and structures
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are given in generic form, for example, \fBpcre_compile()\fP. The actual
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names used in the libraries have a suffix _8, _16, or _32, as appropriate.
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.
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.
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.SH "INPUT ENCODING"
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.rs
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.sp
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Input to \fBpcre2test\fP is processed line by line, either by calling the C
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library's \fBfgets()\fP function, or via the \fBlibreadline\fP library (see
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below). In Unix-like environments, \fBfgets()\fP treats any bytes other than
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newline as data characters. However, in some Windows environments character 26
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(hex 1A) causes an immediate end of file, and no further data is read. For
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maximum portability, therefore, it is safest to avoid non-printing characters
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in \fBpcre2test\fP input files.
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.
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.
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.SH "COMMAND LINE OPTIONS"
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.rs
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.TP 10
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\fB-8\fP
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If the 8-bit library has been built, this option causes it to be used (this is
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the default). If the 8-bit library has not been built, this option causes an
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error.
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.TP 10
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\fB-16\fP
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If the 16-bit library has been built, this option causes it to be used. If only
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the 16-bit library has been built, this is the default. If the 16-bit library
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has not been built, this option causes an error.
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.TP 10
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\fB-32\fP
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If the 32-bit library has been built, this option causes it to be used. If only
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the 32-bit library has been built, this is the default. If the 32-bit library
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has not been built, this option causes an error.
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.TP 10
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\fB-b\fP
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Behave as if each pattern has the \fB/fullbincode\fP modifier; the full
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internal binary form of the pattern is output after compilation.
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.TP 10
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\fB-C\fP
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Output the version number of the PCRE2 library, and all available information
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about the optional features that are included, and then exit with zero exit
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code. All other options are ignored.
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.TP 10
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\fB-C\fP \fIoption\fP
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Output information about a specific build-time option, then exit. This
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functionality is intended for use in scripts such as \fBRunTest\fP. The
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following options output the value and set the exit code as indicated:
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.sp
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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 \eR matches:
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ANYCRLF or ANY
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exit code is always 0
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.sp
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The following options output 1 for true or 0 for false, and set the exit code
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to the same value:
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.sp
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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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.sp
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If an unknown option is given, an error message is output; the exit code is 0.
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.TP 10
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\fB-d\fP
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Behave as if each pattern has the \fBdebug\fP modifier; the internal
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form and information about the compiled pattern is output after compilation;
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\fB-d\fP is equivalent to \fB-b -i\fP.
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.TP 10
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\fB-dfa\fP
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Behave as if each subject line has the \fBdfa\fP modifier; matching is done
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using the \fBpcre2_dfa_match()\fP function instead of the default
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\fBpcre2_match()\fP.
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.TP 10
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\fB-help\fP
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Output a brief summary these options and then exit.
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.TP 10
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\fB-i\fP
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Behave as if each pattern has the \fB/info\fP modifier; information about the
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compiled pattern is given after compilation.
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.TP 10
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\fB-jit\fP
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Behave as if each pattern line has the \fBjit\fP modifier; after successful
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compilation, each pattern is passed to the just-in-time compiler, if available.
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.TP 10
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\fB-pattern\fB \fImodifier-list\fP
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Behave as if each pattern line contains the given modifiers.
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.TP 10
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\fB-q\fP
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Do not output the version number of \fBpcre2test\fP at the start of execution.
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.TP 10
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\fB-S\fP \fIsize\fP
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On Unix-like systems, set the size of the run-time stack to \fIsize\fP
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megabytes.
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.TP 10
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\fB-subject\fP \fImodifier-list\fP
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Behave as if each subject line contains the given modifiers.
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.TP 10
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\fB-t\fP
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Run each compile and match many times with a timer, and output the resulting
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times per compile or match. When JIT is used, separate times are given for the
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initial compile and the JIT compile. You can control the number of iterations
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that are used for timing by following \fB-t\fP with a number (as a separate
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item on the command line). For example, "-t 1000" iterates 1000 times. The
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default is to iterate 500,000 times.
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.TP 10
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\fB-tm\fP
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This is like \fB-t\fP except that it times only the matching phase, not the
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compile phase.
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.TP 10
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\fB-T\fP \fB-TM\fP
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These behave like \fB-t\fP and \fB-tm\fP, but in addition, at the end of a run,
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the total times for all compiles and matches are output.
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.TP 10
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\fB-version\fP
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Output the PCRE2 version number and then exit.
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.
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.
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.SH "DESCRIPTION"
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.rs
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.sp
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If \fBpcre2test\fP is given two filename arguments, it reads from the first and
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writes to the second. If the first name is "-", input is taken from the
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standard input. If \fBpcre2test\fP is given only one argument, it reads from
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that file and writes to stdout. Otherwise, it reads from stdin and writes to
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stdout. When the input is a terminal, it prompts for each line of input, using
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"re>" to prompt for regular expression patterns, and "data>" to prompt for
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subject lines.
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.P
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When \fBpcre2test\fP is built, a configuration option can specify that it
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should be linked with the \fBlibreadline\fP or \fBlibedit\fP library. When this
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is done, if the input is from a terminal, it is read using the \fBreadline()\fP
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function. This provides line-editing and history facilities. The output from
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the \fB-help\fP option states whether or not \fBreadline()\fP will be used.
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.P
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The program handles any number of tests, each of which consists of a set of
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input lines. Each set starts with a regular expression pattern, followed by any
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number of subject lines to be matched against that pattern. In between sets of
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test data, command lines that begin with a hash (#) character may appear. This
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file format, with some restrictions, can also be processed by the
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\fBperltest.sh\fP script that is distributed with PCRE2 as a means of checking
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that the behaviour of PCRE2 and Perl is the same.
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.P
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Each subject line is matched separately and independently. If you want to do
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multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
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etc., depending on the newline setting) in a single line of input to encode the
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newline sequences. There is no limit on the length of subject lines; the input
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buffer is automatically extended if it is too small. There is a replication
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feature that makes it possible to generate long subject lines without having to
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supply them explicitly.
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.P
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An empty line or the end of the file signals the end of the subject lines for a
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test, at which point a new pattern or command line is expected if there is
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still input to be read.
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.
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.
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.SH "COMMAND LINES"
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.rs
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.sp
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In between sets of test data, a line that begins with a hash (#) character is
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interpreted as a command line. If the first character is followed by white
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space or 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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.sp
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#forbid_utf
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.sp
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Subsequent patterns automatically have the PCRE2_NEVER_UTF and PCRE2_NEVER_UCP
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options set, which locks out the use of UTF and Unicode property features. This
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is a trigger guard that is used in test files to ensure that UTF/Unicode tests
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are not accidentally added to files that are used when UTF support is not
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included in the library. This effect can also be obtained by the use of
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\fB#pattern\fP; the difference is that \fB#forbid_utf\fP cannot be unset, and
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the automatic options are not displayed in pattern information, to avoid
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cluttering up test output.
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.sp
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#pattern <modifier-list>
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.sp
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This command sets a default modifier list that applies to all subsequent
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patterns. Modifiers on a pattern can change these settings.
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.sp
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#perltest
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.sp
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The appearance of this line causes all subsequent modifier settings to be
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checked for compatibility with the \fBperltest.sh\fP script, which is used to
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confirm that Perl gives the same results as PCRE2. Also, apart from comment
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lines, none of the other command lines are permitted, because they and many
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of the modifiers are specific to \fBpcre2test\fP, and should not be used in
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test files that are also processed by \fBperltest.sh\fP. The \fP#perltest\fB
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command helps detect tests that are accidentally put in the wrong file.
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.sp
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#subject <modifier-list>
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.sp
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This command sets a default modifier list that applies to all subsequent
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subject lines. Modifiers on a subject line can change these settings.
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.
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.
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.SH "MODIFIER SYNTAX"
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.rs
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.sp
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Modifier lists are used with both pattern and subject lines. Items in a list
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are separated by commas and optional white space. Some modifiers may be given
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for both patterns and subject lines, whereas others are valid for one or the
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other only. Each modifier has a long name, for example "anchored", and some of
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them must be followed by an equals sign and a value, for example, "offset=12".
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Modifiers that do not take values may be preceded by a minus sign to turn off a
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previous setting.
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.P
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A few of the more common modifiers can also be specified as single letters, for
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example "i" for "caseless". In documentation, following the Perl convention,
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these are written with a slash ("the /i modifier") for clarity. Abbreviated
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modifiers must all be concatenated in the first item of a modifier list. If the
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first item is not recognized as a long modifier name, it is interpreted as a
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sequence of these abbreviations. For example:
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.sp
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/abc/ig,newline=cr,jit=3
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.sp
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This is a pattern line whose modifier list starts with two one-letter modifiers
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(/i and /g). The lower-case abbreviated modifiers are the same as used in Perl.
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.
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.
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.SH "PATTERN SYNTAX"
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.rs
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.sp
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A pattern line must start with one of the following characters (common symbols,
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excluding pattern meta-characters):
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.sp
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/ ! " ' ` - = _ : ; , % & @ ~
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.sp
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This is interpreted as the pattern's delimiter. A regular expression may be
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continued over several input lines, in which case the newline characters are
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included within it. It is possible to include the delimiter within the pattern
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by escaping it with a backslash, for example
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.sp
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/abc\e/def/
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.sp
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If you do this, the escape and the delimiter form part of the pattern, but
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since the delimiters are all non-alphanumeric, this does not affect its
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interpretation. If the terminating delimiter is immediately followed by a
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backslash, for example,
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.sp
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/abc/\e
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.sp
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then a backslash is added to the end of the pattern. This is done to provide a
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way of testing the error condition that arises if a pattern finishes with a
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backslash, because
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.sp
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/abc\e/
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.sp
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is interpreted as the first line of a pattern that starts with "abc/", causing
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pcre2test to read the next line as a continuation of the regular expression.
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.P
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A pattern can be followed by a modifier list (details below).
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.
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.
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.SH "SUBJECT LINE SYNTAX"
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.rs
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.sp
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Before each subject line is passed to \fBpcre2_match()\fP or
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\fBpcre2_dfa_match()\fP, 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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.sp
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\ea alarm (BEL, \ex07)
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\eb backspace (\ex08)
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\ee escape (\ex27)
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\ef form feed (\ex0c)
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\en newline (\ex0a)
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\er carriage return (\ex0d)
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\et tab (\ex09)
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\ev vertical tab (\ex0b)
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\ennn 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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\eo{dd...} octal character (any number of octal digits}
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\exhh hexadecimal byte (up to 2 hex digits)
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\ex{hh...} hexadecimal character (any number of hex digits)
|
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.sp
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|
The use of \ex{hh...} is not dependent on the use of the \fButf\fP modifier on
|
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the pattern. It is recognized always. There may be any number of hexadecimal
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digits inside the braces; invalid values provoke error messages.
|
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.P
|
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Note that \exhh specifies one byte rather than one character in UTF-8 mode;
|
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this makes it possible to construct invalid UTF-8 sequences for testing
|
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purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in
|
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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, \ex{hh} generates one byte
|
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for values less than 256, and causes an error for greater values.
|
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.P
|
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In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it
|
|
possible to construct invalid UTF-16 sequences for testing purposes.
|
|
.P
|
|
In UTF-32 mode, all 4- to 8-digit \ex{...} values are accepted. This makes it
|
|
possible to construct invalid UTF-32 sequences for testing purposes.
|
|
.P
|
|
There is a special backslash sequence that specifies replication of one or more
|
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characters:
|
|
.sp
|
|
\e[<characters>]{<count>}
|
|
.sp
|
|
This makes it possible to test long strings without having to provide them as
|
|
part of the file. For example:
|
|
.sp
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\e[abc]{4}
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|
.sp
|
|
is converted to "abcabcabcabc". This feature does not support nesting. To
|
|
include a closing square bracket in the characters, code it as \ex5D.
|
|
.P
|
|
A backslash followed by an equals sign marks the end of the subject string and
|
|
the start of a modifier list. For example:
|
|
.sp
|
|
abc\e=notbol,notempty
|
|
.sp
|
|
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.
|
|
.
|
|
.
|
|
.SH "PATTERN MODIFIERS"
|
|
.rs
|
|
.sp
|
|
There are three types of modifier that can appear in pattern lines, two of
|
|
which may also be used in a \fB#pattern\fP command. A pattern's modifier list
|
|
can add to or override default modifiers that were set by a previous
|
|
\fB#pattern\fP command.
|
|
.
|
|
.
|
|
.SS "Setting compilation options"
|
|
.rs
|
|
.sp
|
|
The following modifiers set options for \fBpcre2_compile()\fP. The most common
|
|
ones have single-letter abbreviations. See
|
|
.\" HREF
|
|
\fBpcreapi\fP
|
|
.\"
|
|
for a description of their effects.
|
|
.sp
|
|
allow_empty_class set PCRE2_ALLOW_EMPTY_CLASS
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|
alt_bsux set PCRE2_ALT_BSUX
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|
anchored set PCRE2_ANCHORED
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auto_callout set PCRE2_AUTO_CALLOUT
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/i caseless set PCRE2_CASELESS
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dollar_endonly set PCRE2_DOLLAR_ENDONLY
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/s dotall set PCRE2_DOTALL
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dupnames set PCRE2_DUPNAMES
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/x extended set PCRE2_EXTENDED
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firstline set PCRE2_FIRSTLINE
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match_unset_backref set PCRE2_MATCH_UNSET_BACKREF
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/m multiline set PCRE2_MULTILINE
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never_ucp set PCRE2_NEVER_UCP
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never_utf set PCRE2_NEVER_UTF
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no_auto_capture set PCRE2_NO_AUTO_CAPTURE
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|
no_auto_possess set PCRE2_NO_AUTO_POSSESS
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no_start_optimize set PCRE2_NO_START_OPTIMIZE
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|
no_utf_check set PCRE2_NO_UTF_CHECK
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ucp set PCRE2_UCP
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|
ungreedy set PCRE2_UNGREEDY
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|
utf set PCRE2_UTF
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|
.sp
|
|
As well as turning on the PCRE2_UTF option, the \fButf\fP modifier causes all
|
|
non-printing characters in output strings to be printed using the \ex{hh...}
|
|
notation. Otherwise, those less than 0x100 are output in hex without the curly
|
|
brackets.
|
|
.
|
|
.
|
|
.SS "Setting compilation controls"
|
|
.rs
|
|
.sp
|
|
The following modifiers affect the compilation process or request information
|
|
about the pattern:
|
|
.sp
|
|
bsr=[anycrlf|unicode] specify \eR handling
|
|
/B bincode show binary code without lengths
|
|
debug same as info,fullbincode
|
|
fullbincode show binary code with lengths
|
|
/I info show info about compiled pattern
|
|
hex pattern is coded in hexadecimal
|
|
jit[=<number>] use JIT
|
|
jitfast use JIT fast path
|
|
jitverify verify JIT use
|
|
locale=<name> use this locale
|
|
memory show memory used
|
|
newline=<type> set newline type
|
|
parens_nest_limit=<n> set maximum parentheses depth
|
|
perlcompat lock out non-Perl modifiers
|
|
posix use the POSIX API
|
|
stackguard=<number> test the stackguard feature
|
|
tables=[0|1|2] select internal tables
|
|
.sp
|
|
The effects of these modifiers are described in the following sections.
|
|
.
|
|
.
|
|
.SS "Newline and \eR handling"
|
|
.rs
|
|
.sp
|
|
The \fBbsr\fP modifier specifies what \eR in a pattern should match. If it is
|
|
set to "anycrlf", \eR matches CR, LF, or CRLF only. If it is set to "unicode",
|
|
\eR matches any Unicode newline sequence. The default is specified when PCRE2
|
|
is built, with the default default being Unicode.
|
|
.P
|
|
The \fBnewline\fP 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).
|
|
.
|
|
.
|
|
.SS "Information about a pattern"
|
|
.rs
|
|
.sp
|
|
The \fBdebug\fP modifier is a shorthand for \fBinfo,fullbincode\fP, requesting
|
|
all available information.
|
|
.P
|
|
The \fBbincode\fP 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 different internal
|
|
link sizes and different code unit widths. By using \fBbincode\fP, the same
|
|
regression tests can be used in different environments.
|
|
.P
|
|
The \fBfullbincode\fP modifier, by contrast, \fIdoes\fP 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.
|
|
.P
|
|
The \fBinfo\fP 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 \fBpcre2_pattern_info()\fP function. Here are
|
|
some typical examples:
|
|
.sp
|
|
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
|
|
.sp
|
|
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
|
|
.sp
|
|
"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.
|
|
.
|
|
.
|
|
.SS "Specifying a pattern in hex"
|
|
.rs
|
|
.sp
|
|
The \fBhex\fP modifier specifies that the characters of the pattern are to be
|
|
interpreted as pairs of hexadecimal digits. White space is permitted between
|
|
pairs. For example:
|
|
.sp
|
|
/ab 32 59/hex
|
|
.sp
|
|
This feature is provided as a way of creating patterns that contain binary zero
|
|
and other non-printing characters. By default, \fBpcre2test\fP passes patterns
|
|
as zero-terminated strings to \fBpcre2_compile()\fP, giving the length as
|
|
PCRE2_ZERO_TERMINATED. However, for patterns specified in hexadecimal, the
|
|
actual length of the pattern is passed.
|
|
.
|
|
.
|
|
.SS "JIT compilation"
|
|
.rs
|
|
.sp
|
|
The \fB/jit\fP modifier may optionally be followed by an equals sign and a
|
|
number in the range 0 to 7:
|
|
.sp
|
|
0 disable JIT
|
|
1 use JIT for normal match only
|
|
2 use JIT for soft partial match only
|
|
3 use JIT for normal match and soft partial match
|
|
4 use JIT for hard partial match only
|
|
6 use JIT for soft and hard partial match
|
|
7 all three modes
|
|
.sp
|
|
If no number is given, 7 is assumed. If JIT compilation is successful, the
|
|
compiled JIT code will automatically be used when \fBpcre2_match()\fP is run
|
|
for the appropriate type of match, except when incompatible run-time options
|
|
are specified. For more details, see the
|
|
.\" HREF
|
|
\fBpcre2jit\fP
|
|
.\"
|
|
documentation. See also the \fBjitstack\fP modifier below for a way of
|
|
setting the size of the JIT stack.
|
|
.P
|
|
If the \fBjitfast\fP modifier is specified, matching is done using the JIT
|
|
"fast path" interface, \fBpcre2_jit_match(), which skips some of the sanity
|
|
checks that are done by \fBpcre2_match()\fP, and of course does not work when
|
|
JIT is not supported. If \fBjitfast\fP is specified without \fBjit\fP, jit=7 is
|
|
assumed.
|
|
.P
|
|
If the \fBjitverify\fP modifier is specified, information about the compiled
|
|
pattern shows whether JIT compilation was or was not successful. If
|
|
\fBjitverify\fP is specified without \fBjit\fP, jit=7 is assumed. If JIT
|
|
compilation is successful when \fBjitverify\fP 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.
|
|
.
|
|
.
|
|
.SS "Setting a locale"
|
|
.rs
|
|
.sp
|
|
The \fB/locale\fP modifier must specify the name of a locale, for example:
|
|
.sp
|
|
/pattern/locale=fr_FR
|
|
.sp
|
|
The given locale is set, \fBpcre2_maketables()\fP is called to build a set of
|
|
character tables for the locale, and this is then passed to
|
|
\fBpcre2_compile()\fP when compiling the regular expression. The same tables
|
|
are used when matching the following subject lines. The \fB/locale\fP modifier
|
|
applies only to the pattern on which it appears, but can be given in a
|
|
\fB#pattern\fP command if a default is needed. Setting a locale and alternate
|
|
character tables are mutually exclusive.
|
|
.
|
|
.
|
|
.SS "Showing pattern memory"
|
|
.rs
|
|
.sp
|
|
The \fB/memory\fP 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
|
|
\fBpcre2_code\fP block; it is just the actual compiled data. If the pattern is
|
|
subsequently passed to the JIT compiler, the size of the JIT compiled code is
|
|
also output. Here is an example:
|
|
.sp
|
|
re> /a(b)c/jit,memory
|
|
Memory allocation (code space): 21
|
|
Memory allocation (JIT code): 1910
|
|
.sp
|
|
.
|
|
.
|
|
.SS "Limiting nested parentheses"
|
|
.rs
|
|
.sp
|
|
The \fBparens_nest_limit\fP 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 \fBpcre2test\fP
|
|
sets its own default of 220, which is required for running the standard test
|
|
suite.
|
|
.
|
|
.
|
|
.SS "Using the POSIX wrapper API"
|
|
.rs
|
|
.sp
|
|
The \fB/posix\fP modifier causes \fBpcre2test\fP to call PCRE2 via the POSIX
|
|
wrapper API rather than its native API. This supports only the 8-bit library.
|
|
When the POSIX API is being used, the following pattern modifiers set options
|
|
for the \fBregcomp()\fP function:
|
|
.sp
|
|
caseless REG_ICASE
|
|
multiline REG_NEWLINE
|
|
no_auto_capture REG_NOSUB
|
|
dotall REG_DOTALL )
|
|
ungreedy REG_UNGREEDY ) These options are not part of
|
|
ucp REG_UCP ) the POSIX standard
|
|
utf REG_UTF8 )
|
|
.sp
|
|
The \fBaftertext\fP and \fBallaftertext\fP subject modifiers work as described
|
|
below. All other modifiers cause an error.
|
|
.
|
|
.
|
|
.SS "Testing the stack guard feature"
|
|
.rs
|
|
.sp
|
|
The \fB/stackguard\fP modifier is used to test the use of
|
|
\fBpcre2_set_compile_recursion_guard()\fP, a function that is provided to
|
|
enable stack availability to be checked during compilation (see the
|
|
.\" HREF
|
|
\fBpcre2api\fP
|
|
.\"
|
|
documentation for details). If the number specified by the modifier is greater
|
|
than zero, \fBpcre2_set_compile_recursion_guard()\fP is called to set up
|
|
callback from \fBpcre2_compile()\fP 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.
|
|
.
|
|
.
|
|
.SS "Using alternative character tables"
|
|
.rs
|
|
.sp
|
|
The value specified for the \fB/tables\fP 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
|
|
\fBpcre2_compile()\fP. This is used in the PCRE2 tests to check behaviour with
|
|
different character tables. The digit specifies the tables as follows:
|
|
.sp
|
|
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
|
|
.sp
|
|
In table 2, some characters whose codes are greater than 128 are identified as
|
|
letters, digits, spaces, etc. Setting alternate character tables and a locale
|
|
are mutually exclusive.
|
|
.
|
|
.
|
|
.SS "Setting certain match controls"
|
|
.rs
|
|
.sp
|
|
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 do
|
|
not affect the compilation process.
|
|
.sp
|
|
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
|
|
.sp
|
|
These modifiers may not appear in a \fB#pattern\fP command. If you want them as
|
|
defaults, set them in a \fB#subject\fP command.
|
|
.
|
|
.
|
|
.SH "SUBJECT MODIFIERS"
|
|
.rs
|
|
.sp
|
|
The modifiers that can appear in subject lines and the \fB#subject\fP
|
|
command are of two types.
|
|
.
|
|
.
|
|
.SS "Setting match options"
|
|
.rs
|
|
.sp
|
|
The following modifiers set options for \fBpcre2_match()\fP or
|
|
\fBpcre2_dfa_match()\fP. See
|
|
.\" HREF
|
|
\fBpcreapi\fP
|
|
.\"
|
|
for a description of their effects.
|
|
.sp
|
|
anchored set PCRE2_ANCHORED
|
|
dfa_restart set PCRE2_DFA_RESTART
|
|
dfa_shortest set PCRE2_DFA_SHORTEST
|
|
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
|
|
.sp
|
|
The partial matching modifiers are provided with abbreviations because they
|
|
appear frequently in tests.
|
|
.P
|
|
If the \fB/posix\fP modifier was present on the pattern, causing the POSIX
|
|
wrapper API to be used, the only option-setting modifiers that have any effect
|
|
are \fBnotbol\fP, \fBnotempty\fP, and \fBnoteol\fP, causing REG_NOTBOL,
|
|
REG_NOTEMPTY, and REG_NOTEOL, respectively, to be passed to \fBregexec()\fP.
|
|
Any other modifiers cause an error.
|
|
.
|
|
.
|
|
.SS "Setting match controls"
|
|
.rs
|
|
.sp
|
|
The following modifiers affect the matching process or request additional
|
|
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.
|
|
.sp
|
|
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_fail=<n>[:<m>] control callout failure
|
|
callout_none do not supply a callout function
|
|
copy=<number or name> copy captured substring
|
|
dfa use \fBpcre2_dfa_match()\fP
|
|
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
|
|
offset=<n> set starting offset
|
|
ovector=<n> set size of output vector
|
|
recursion_limit=<n> set a recursion limit
|
|
replace=<string> specify a replacement string
|
|
startchar show startchar when relevant
|
|
zero_terminate pass the subject as zero-terminated
|
|
.sp
|
|
The effects of these modifiers are described in the following sections.
|
|
.
|
|
.
|
|
.SS "Showing more text"
|
|
.rs
|
|
.sp
|
|
The \fBaftertext\fP modifier requests that as well as outputting the part of
|
|
the subject string that matched the entire pattern, \fBpcre2test\fP 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
|
|
\fBallaftertext\fP modifier requests the same action for captured substrings as
|
|
well as the main matched substring. In each case the remainder is output on the
|
|
following line with a plus character following the capture number.
|
|
.P
|
|
The \fBallusedtext\fP 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
|
|
\eK is used in the pattern. Characters that precede or follow the start and end
|
|
of the actual match are indicated in the output by '<' or '>' characters
|
|
underneath them. Here is an example:
|
|
.sp
|
|
re> /(?<=pqr)abc(?=xyz)/
|
|
data> 123pqrabcxyz456\e=allusedtext
|
|
0: pqrabcxyz
|
|
<<< >>>
|
|
.sp
|
|
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).
|
|
.P
|
|
The \fBstartchar\fP 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 \eK 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:
|
|
.sp
|
|
re> /abc\eKxyz/
|
|
data> abcxyz\e=startchar
|
|
0: abcxyz
|
|
^^^
|
|
.sp
|
|
Unlike \fBallusedtext\fP, the \fBstartchar\fP modifier can be used with JIT.
|
|
However, these two modifiers are mutually exclusive.
|
|
.
|
|
.
|
|
.SS "Showing the value of all capture groups"
|
|
.rs
|
|
.sp
|
|
The \fBallcaptures\fP modifier requests that the values of all potential
|
|
captured 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 \fBpcre2_match()\fP). Groups that did not take part in the match
|
|
are output as "<unset>".
|
|
.
|
|
.
|
|
.SS "Testing callouts"
|
|
.rs
|
|
.sp
|
|
A callout function is supplied when \fBpcre2test\fP calls the library matching
|
|
functions, unless \fBcallout_none\fP is specified. If \fBcallout_capture\fP is
|
|
set, the current captured groups are output when a callout occurs.
|
|
.P
|
|
The \fBcallout_fail\fP modifier can be given one or two numbers. If there is
|
|
only one number, 1 is returned instead of 0 when a callout of that number is
|
|
reached. If two numbers are given, 1 is returned when callout <n> is reached
|
|
for the <m>th time.
|
|
.P
|
|
The \fBcallout_data\fP modifier can be given an unsigned or a negative number.
|
|
Any value other than zero is used as a return from \fBpcre2test\fP's callout
|
|
function.
|
|
.
|
|
.
|
|
.SS "Finding all matches in a string"
|
|
.rs
|
|
.sp
|
|
Searching for all possible matches within a subject can be requested by the
|
|
\fBglobal\fP or \fB/altglobal\fP modifier. After finding a match, the matching
|
|
function is called again to search the remainder of the subject. The difference
|
|
between \fBglobal\fP and \fBaltglobal\fP is that the former uses the
|
|
\fIstart_offset\fP argument to \fBpcre2_match()\fP or \fBpcre2_dfa_match()\fP
|
|
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 lookbehind
|
|
assertion (including \eb or \eB).
|
|
.P
|
|
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 \fB/g\fP modifier or
|
|
the \fBsplit()\fP 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.
|
|
.
|
|
.
|
|
.SS "Testing substring extraction functions"
|
|
.rs
|
|
.sp
|
|
The \fBcopy\fP and \fBget\fP modifiers can be used to test the
|
|
\fBpcre2_substring_copy_xxx()\fP and \fBpcre2_substring_get_xxx()\fP functions.
|
|
They can be given more than once, and each can specify a group name or number,
|
|
for example:
|
|
.sp
|
|
abcd\e=copy=1,copy=3,get=G1
|
|
.sp
|
|
If the \fB#subject\fP command is used to set default copy and/or get lists,
|
|
these can be unset by specifying a negative number to cancel all numbered
|
|
groups and an empty name to cancel all named groups.
|
|
.P
|
|
The \fBgetall\fP modifier tests \fBpcre2_substring_list_get()\fP, which
|
|
extracts all captured substrings.
|
|
.P
|
|
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.
|
|
.
|
|
.
|
|
.SS "Testing the substitution function"
|
|
.rs
|
|
.sp
|
|
If the \fBreplace\fP modifier is set, the \fBpcre2_substitute()\fP function is
|
|
called instead of one of the matching functions. Unlike subject strings,
|
|
\fBpcre2test\fP 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 provides a means of passing an invalid UTF-8 string for testing
|
|
purposes.
|
|
.P
|
|
If the \fBglobal\fP modifier is set, PCRE2_SUBSTITUTE_GLOBAL is passed to
|
|
\fBpcre2_substitute()\fP. After a successful substitution, the modified string
|
|
is output, preceded by the number of replacements. This may be zero if there
|
|
were no matches. Here is a simple example of a substitution test:
|
|
.sp
|
|
/abc/replace=xxx
|
|
=abc=abc=
|
|
1: =xxx=abc=
|
|
=abc=abc=\e=global
|
|
2: =xxx=xxx=
|
|
.sp
|
|
Subject and replacement strings should be kept relatively short 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 \fBpcre2_substitute()\fP 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:
|
|
.sp
|
|
/abc/
|
|
123abc123\e=replace=[10]XYZ
|
|
1: 123XYZ123
|
|
123abc123\e=replace=[9]XYZ
|
|
Failed: error -47: no more memory
|
|
.sp
|
|
A replacement string is ignored with POSIX and DFA matching. Specifying partial
|
|
matching provokes an error return ("bad option value") from
|
|
\fBpcre2_substitute()\fP.
|
|
.
|
|
.
|
|
.SS "Setting the JIT stack size"
|
|
.rs
|
|
.sp
|
|
The \fBjitstack\fP 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.
|
|
.
|
|
.
|
|
.SS "Setting match and recursion limits"
|
|
.rs
|
|
.sp
|
|
The \fBmatch_limit\fP and \fBrecursion_limit\fP modifiers set the appropriate
|
|
limits in the match context. These values are ignored when the
|
|
\fBfind_limits\fP modifier is specified.
|
|
.
|
|
.
|
|
.SS "Finding minimum limits"
|
|
.rs
|
|
.sp
|
|
If the \fBfind_limits\fP modifier is present, \fBpcre2test\fP calls
|
|
\fBpcre2_match()\fP several times, setting different values in the match
|
|
context via \fBpcre2_set_match_limit()\fP and \fBpcre2_set_recursion_limit()\fP
|
|
until it finds the minimum values for each parameter that allow
|
|
\fBpcre2_match()\fP to complete without error.
|
|
.P
|
|
If JIT is being used, only the match limit is relevant. If DFA matching is
|
|
being used, neither limit is relevant, and this modifier is ignored (with a
|
|
warning message).
|
|
.P
|
|
The \fImatch_limit\fP 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 \fImatch_limit_recursion\fP number is
|
|
a measure of how much stack (or, if PCRE2 is compiled with NO_RECURSE, how much
|
|
heap) memory is needed to complete the match attempt.
|
|
.
|
|
.
|
|
.SS "Showing MARK names"
|
|
.rs
|
|
.sp
|
|
.P
|
|
The \fBmark\fP modifier causes the names from backtracking control verbs that
|
|
are returned from calls to \fBpcre2_match()\fP to be displayed. If a mark is
|
|
returned for a match, non-match, or partial match, \fBpcre2test\fP shows it.
|
|
For a match, it is on a line by itself, tagged with "MK:". Otherwise, it
|
|
is added to the non-match message.
|
|
.
|
|
.
|
|
.SS "Showing memory usage"
|
|
.rs
|
|
.sp
|
|
The \fBmemory\fP modifier causes \fBpcre2test\fP to log all memory allocation
|
|
and freeing calls that occur during a match operation.
|
|
.
|
|
.
|
|
.SS "Setting a starting offset"
|
|
.rs
|
|
.sp
|
|
The \fBoffset\fP modifier sets an offset in the subject string at which
|
|
matching starts. Its value is a number of code units, not characters.
|
|
.
|
|
.
|
|
.SS "Setting the size of the output vector"
|
|
.rs
|
|
.sp
|
|
The \fBovector\fP 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
|
|
\fB#subject\fP command. It specifies the number of pairs of offsets that are
|
|
available for storing matching information. The default is 15.
|
|
.P
|
|
A value of zero is useful when testing the POSIX API because it causes
|
|
\fBregexec()\fP to be called with a NULL capture vector. When not testing the
|
|
POSIX API, a value of zero is used to cause
|
|
\fBpcre2_match_data_create_from_pattern()\fP 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.)
|
|
.
|
|
.
|
|
.SS "Passing the subject as zero-terminated"
|
|
.rs
|
|
.sp
|
|
By default, the subject string is passed to a native API matching function with
|
|
its correct length. In order to test the facility for passing a zero-terminated
|
|
string, the \fBzero_terminate\fP 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.)
|
|
.P
|
|
When testing \fBpcre2_substitute()\fP, this modifier also has the effect of
|
|
passing the replacement string as zero-terminated.
|
|
.
|
|
.
|
|
.SH "THE ALTERNATIVE MATCHING FUNCTION"
|
|
.rs
|
|
.sp
|
|
By default, \fBpcre2test\fP uses the standard PCRE2 matching function,
|
|
\fBpcre2_match()\fP to match each subject line. PCRE2 also supports an
|
|
alternative matching function, \fBpcre2_dfa_match()\fP, which operates in a
|
|
different way, and has some restrictions. The differences between the two
|
|
functions are described in the
|
|
.\" HREF
|
|
\fBpcre2matching\fP
|
|
.\"
|
|
documentation.
|
|
.P
|
|
If the \fBdfa\fP modifier is set, the alternative matching function is used.
|
|
This function finds all possible matches at a given point in the subject. If,
|
|
however, the \fBdfa_shortest\fP modifier is set, processing stops after the
|
|
first match is found. This is always the shortest possible match.
|
|
.
|
|
.
|
|
.SH "DEFAULT OUTPUT FROM pcre2test"
|
|
.rs
|
|
.sp
|
|
This section describes the output when the normal matching function,
|
|
\fBpcre2_match()\fP, is being used.
|
|
.P
|
|
When a match succeeds, \fBpcre2test\fP outputs the list of captured substrings,
|
|
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, \eK, \eb,
|
|
or \eB was involved.)
|
|
.P
|
|
For any other return, \fBpcre2test\fP 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 \fBpcre2test\fP run.
|
|
.sp
|
|
$ pcre2test
|
|
PCRE2 version 9.00 2014-05-10
|
|
.sp
|
|
re> /^abc(\ed+)/
|
|
data> abc123
|
|
0: abc123
|
|
1: 123
|
|
data> xyz
|
|
No match
|
|
.sp
|
|
Unset capturing substrings that are not followed by one that is set are not
|
|
shown by \fBpcre2test\fP unless the \fBallcaptures\fP 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.
|
|
.sp
|
|
re> /(a)|(b)/
|
|
data> a
|
|
0: a
|
|
1: a
|
|
data> b
|
|
0: b
|
|
1: <unset>
|
|
2: b
|
|
.sp
|
|
If the strings contain any non-printing characters, they are output as \exhh
|
|
escapes if the value is less than 256 and UTF mode is not set. Otherwise they
|
|
are output as \ex{hh...} escapes. See below for the definition of non-printing
|
|
characters. If the \fB/aftertext\fP modifier is set, the output for substring
|
|
0 is followed by the the rest of the subject string, identified by "0+" like
|
|
this:
|
|
.sp
|
|
re> /cat/aftertext
|
|
data> cataract
|
|
0: cat
|
|
0+ aract
|
|
.sp
|
|
If global matching is requested, the results of successive matching attempts
|
|
are output in sequence, like this:
|
|
.sp
|
|
re> /\eBi(\ew\ew)/g
|
|
data> Mississippi
|
|
0: iss
|
|
1: ss
|
|
0: iss
|
|
1: ss
|
|
0: ipp
|
|
1: pp
|
|
.sp
|
|
"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 \fBoffset\fP
|
|
modifier is past the end of the subject string):
|
|
.sp
|
|
re> /xyz/
|
|
data> xyz\e=offset=4
|
|
Error -24 (bad offset value)
|
|
.P
|
|
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 \en escape (or \er, \er\en, etc.,
|
|
depending on the newline sequence setting).
|
|
.
|
|
.
|
|
.
|
|
.SH "OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION"
|
|
.rs
|
|
.sp
|
|
When the alternative matching function, \fBpcre2_dfa_match()\fP, 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:
|
|
.sp
|
|
re> /(tang|tangerine|tan)/
|
|
data> yellow tangerine\e=dfa
|
|
0: tangerine
|
|
1: tang
|
|
2: tan
|
|
.sp
|
|
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 assertion, \eb, or \eB was involved. (\eK is not
|
|
supported for DFA matching.)
|
|
.P
|
|
If global matching is requested, the search for further matches resumes
|
|
at the end of the longest match. For example:
|
|
.sp
|
|
re> /(tang|tangerine|tan)/g
|
|
data> yellow tangerine and tangy sultana\e=dfa
|
|
0: tangerine
|
|
1: tang
|
|
2: tan
|
|
0: tang
|
|
1: tan
|
|
0: tan
|
|
.sp
|
|
The alternative matching function does not support substring capture, so the
|
|
modifiers that are concerned with captured substrings are not relevant.
|
|
.
|
|
.
|
|
.SH "RESTARTING AFTER A PARTIAL MATCH"
|
|
.rs
|
|
.sp
|
|
When the alternative matching function has given the PCRE2_ERROR_PARTIAL
|
|
return, indicating that the subject partially matched the pattern, you can
|
|
restart the match with additional subject data by means of the
|
|
\fBdfa_restart\fP modifier. For example:
|
|
.sp
|
|
re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
|
|
data> 23ja\e=P,dfa
|
|
Partial match: 23ja
|
|
data> n05\e=dfa,dfa_restart
|
|
0: n05
|
|
.sp
|
|
For further information about partial matching, see the
|
|
.\" HREF
|
|
\fBpcre2partial\fP
|
|
.\"
|
|
documentation.
|
|
.
|
|
.
|
|
.SH CALLOUTS
|
|
.rs
|
|
.sp
|
|
If the pattern contains any callout requests, \fBpcre2test\fP's callout
|
|
function is called during matching. This works with both matching functions. 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:
|
|
.sp
|
|
--->pqrabcdef
|
|
0 ^ ^ \ed
|
|
.sp
|
|
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 \ed. Just
|
|
one circumflex is output if the start and current positions are the same.
|
|
.P
|
|
Callouts numbered 255 are assumed to be automatic callouts, inserted as a
|
|
result of the \fB/auto_callout\fP pattern modifier. In this case, instead of
|
|
showing the callout number, the offset in the pattern, preceded by a plus, is
|
|
output. For example:
|
|
.sp
|
|
re> /\ed?[A-E]\e*/auto_callout
|
|
data> E*
|
|
--->E*
|
|
+0 ^ \ed?
|
|
+3 ^ [A-E]
|
|
+8 ^^ \e*
|
|
+10 ^ ^
|
|
0: E*
|
|
.sp
|
|
If a pattern contains (*MARK) items, an additional line is output whenever
|
|
a change of latest mark is passed to the callout function. For example:
|
|
.sp
|
|
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
|
|
.sp
|
|
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.
|
|
.P
|
|
The callout function in \fBpcre2test\fP returns zero (carry on matching) by
|
|
default, but you can use a \fBcallout_fail\fP modifier in a subject line (as
|
|
described above) to change this and other parameters of the callout.
|
|
.P
|
|
Inserting callouts can be helpful when using \fBpcre2test\fP to check
|
|
complicated regular expressions. For further information about callouts, see
|
|
the
|
|
.\" HREF
|
|
\fBpcre2callout\fP
|
|
.\"
|
|
documentation.
|
|
.
|
|
.
|
|
.
|
|
.SH "NON-PRINTING CHARACTERS"
|
|
.rs
|
|
.sp
|
|
When \fBpcre2test\fP 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.
|
|
.P
|
|
When \fBpcre2test\fP 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 \fB/locale\fP modifier). In this case, the
|
|
\fBisprint()\fP function is used to distinguish printing and non-printing
|
|
characters.
|
|
.
|
|
.
|
|
.
|
|
.SH "SEE ALSO"
|
|
.rs
|
|
.sp
|
|
\fBpcre2\fP(3), \fBpcre2api\fP(3), \fBpcre2callout\fP(3),
|
|
\fBpcre2jit\fP, \fBpcre2matching\fP(3), \fBpcre2partial\fP(d),
|
|
\fBpcre2pattern\fP(3).
|
|
.
|
|
.
|
|
.SH AUTHOR
|
|
.rs
|
|
.sp
|
|
.nf
|
|
Philip Hazel
|
|
University Computing Service
|
|
Cambridge, England.
|
|
.fi
|
|
.
|
|
.
|
|
.SH REVISION
|
|
.rs
|
|
.sp
|
|
.nf
|
|
Last updated: 23 November 2014
|
|
Copyright (c) 1997-2014 University of Cambridge.
|
|
.fi
|