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README file for PCRE (Perl-compatible regular expressions) |
README file for PCRE (Perl-compatible regular expressions) |
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* IMPORTANT FOR THOSE UPGRADING FROM VERSIONS BEFORE 2.00 * |
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* * |
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* Please note that there has been a change in the API such that a larger * |
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* ovector is required at matching time, to provide some additional workspace. * |
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* The new man page has details. This change was necessary in order to support * |
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* some of the new functionality in Perl 5.005. * |
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******************************************************************************* |
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The distribution should contain the following files: |
The distribution should contain the following files: |
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ChangeLog log of changes to the code |
ChangeLog log of changes to the code |
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Makefile for building PCRE |
Makefile for building PCRE |
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Performance notes on performance |
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README this file |
README this file |
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RunTest a shell script for running tests |
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Tech.Notes notes on the encoding |
Tech.Notes notes on the encoding |
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pcre.3 man page for the functions |
pcre.3 man page for the functions |
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pcreposix.3 man page for the POSIX wrapper API |
pcreposix.3 man page for the POSIX wrapper API |
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pgrep.1 man page for pgrep |
pgrep.1 man page for pgrep |
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pgrep.c source of a grep utility that uses PCRE |
pgrep.c source of a grep utility that uses PCRE |
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perltest Perl test program |
perltest Perl test program |
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testinput test data, compatible with Perl |
testinput test data, compatible with Perl 5.004 and 5.005 |
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testinput2 test data for error messages and non-Perl things |
testinput2 test data for error messages and non-Perl things |
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testinput3 test data, compatible with Perl 5.005 |
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testoutput test results corresponding to testinput |
testoutput test results corresponding to testinput |
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testoutput2 test results corresponding to testinput2 |
testoutput2 test results corresponding to testinput2 |
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testoutput3 test results corresponding to testinpug3 |
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To build PCRE, edit Makefile for your system (it is a fairly simple make file) |
To build PCRE, edit Makefile for your system (it is a fairly simple make file, |
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and then run it. It builds a two libraries called libpcre.a and libpcreposix.a, |
and there are some comments at the top) and then run it. It builds two |
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a test program called pcretest, and the pgrep command. |
libraries called libpcre.a and libpcreposix.a, a test program called pcretest, |
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and the pgrep command. |
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To test PCRE, run pcretest on the file testinput, and compare the output with |
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the contents of testoutput. There should be no differences. For example: |
To test PCRE, run the RunTest script in the pcre directory. This runs pcretest |
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on each of the testinput files in turn, and compares the output with the |
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pcretest testinput some.file |
contents of the corresponding testoutput file. A file called testtry is used to |
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diff some.file testoutput |
hold the output from pcretest (which is documented below). |
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Do the same with testinput2, comparing the output with testoutput2, but this |
To run pcretest on just one of the test files, give its number as an argument |
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time using the -i flag for pcretest, i.e. |
to RunTest, for example: |
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pcretest -i testinput2 some.file |
RunTest 3 |
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diff some.file testoutput2 |
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The first and third test files can also be fed directly into the perltest |
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The make target "runtest" runs both these tests, using the file "testtry" to |
program to check that Perl gives the same results. The third file requires the |
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store the intermediate output, deleting it at the end if all goes well. |
additional features of release 5.005, which is why it is kept separate from the |
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main test input, which needs only Perl 5.004. In the long run, when 5.005 is |
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widespread, these two test files may get amalgamated. |
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There are two sets of tests because the first set can also be fed directly into |
The second set of tests check pcre_info(), pcre_study(), error detection and |
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the perltest program to check that Perl gives the same results. The second set |
run-time flags that are specific to PCRE, as well as the POSIX wrapper API. |
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of tests check pcre_info(), pcre_study(), error detection and run-time flags |
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that are specific to PCRE, as well as the POSIX wrapper API. |
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To install PCRE, copy libpcre.a to any suitable library directory (e.g. |
To install PCRE, copy libpcre.a to any suitable library directory (e.g. |
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/usr/local/lib), pcre.h to any suitable include directory (e.g. |
/usr/local/lib), pcre.h to any suitable include directory (e.g. |
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for the POSIX-style functions is called pcreposix.h. The official POSIX name is |
for the POSIX-style functions is called pcreposix.h. The official POSIX name is |
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regex.h, but I didn't want to risk possible problems with existing files of |
regex.h, but I didn't want to risk possible problems with existing files of |
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that name by distributing it that way. To use it with an existing program that |
that name by distributing it that way. To use it with an existing program that |
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uses the POSIX API it will have to be renamed or pointed at by a link. |
uses the POSIX API, it will have to be renamed or pointed at by a link. |
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Character tables |
Character tables |
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The /D option is a PCRE debugging feature. It causes the internal form of |
The /D option is a PCRE debugging feature. It causes the internal form of |
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compiled regular expressions to be output after compilation. The /S option |
compiled regular expressions to be output after compilation. The /S option |
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causes pcre_study() to be called after the expression has been compiled, and |
causes pcre_study() to be called after the expression has been compiled, and |
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the results used when the expression is matched. If /I is present as well as |
the results used when the expression is matched. |
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/S, then pcre_study() is called with the PCRE_CASELESS option. |
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Finally, the /P option causes pcretest to call PCRE via the POSIX wrapper API |
Finally, the /P option causes pcretest to call PCRE via the POSIX wrapper API |
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rather than its native API. When this is done, all other options except /i and |
rather than its native API. When this is done, all other options except /i and |
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PCRE_DOTALL unless REG_NEWLINE is set. |
PCRE_DOTALL unless REG_NEWLINE is set. |
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A regular expression can extend over several lines of input; the newlines are |
A regular expression can extend over several lines of input; the newlines are |
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included in it. See the testinput file for many examples. |
included in it. See the testinput files for many examples. |
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Before each data line is passed to pcre_exec(), leading and trailing whitespace |
Before each data line is passed to pcre_exec(), leading and trailing whitespace |
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is removed, and it is then scanned for \ escapes. The following are recognized: |
is removed, and it is then scanned for \ escapes. The following are recognized: |
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\A pass the PCRE_ANCHORED option to pcre_exec() |
\A pass the PCRE_ANCHORED option to pcre_exec() |
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\B pass the PCRE_NOTBOL option to pcre_exec() |
\B pass the PCRE_NOTBOL option to pcre_exec() |
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\E pass the PCRE_DOLLAR_ENDONLY option to pcre_exec() |
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\I pass the PCRE_CASELESS option to pcre_exec() |
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\M pass the PCRE_MULTILINE option to pcre_exec() |
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\S pass the PCRE_DOTALL option to pcre_exec() |
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\Odd set the size of the output vector passed to pcre_exec() to dd |
\Odd set the size of the output vector passed to pcre_exec() to dd |
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(any number of decimal digits) |
(any number of decimal digits) |
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\Z pass the PCRE_NOTEOL option to pcre_exec() |
\Z pass the PCRE_NOTEOL option to pcre_exec() |
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Testing Perl-Compatible Regular Expressions |
Testing Perl-Compatible Regular Expressions |
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PCRE version 0.90 08-Sep-1997 |
PCRE version 0.90 08-Sep-1997 |
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re> /^abc(\d+)/ |
re> /^abc(\d+)/ |
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data> abc123 |
data> abc123 |
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0: abc123 |
0: abc123 |
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1: 123 |
1: 123 |
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data> xyz |
data> xyz |
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No match |
No match |
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Note that while patterns can be continued over several lines (a plain ">" |
Note that while patterns can be continued over several lines (a plain ">" |
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If the option -s is given to pcretest, it outputs the size of each compiled |
If the option -s is given to pcretest, it outputs the size of each compiled |
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pattern after it has been compiled. |
pattern after it has been compiled. |
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If the -t option is given, each compile, study, and match is run 2000 times |
If the -t option is given, each compile, study, and match is run 10000 times |
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while being timed, and the resulting time per compile or match is output in |
while being timed, and the resulting time per compile or match is output in |
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milliseconds. Do not set -t with -s, because you will then get the size output |
milliseconds. Do not set -t with -s, because you will then get the size output |
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2000 times and the timing will be distorted. |
10000 times and the timing will be distorted. If you want to change the number |
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of repetitions used for timing, edit the definition of LOOPREPEAT at the top of |
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pcretest.c |
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The perltest program tests Perl's regular expressions; it has the same |
The perltest program tests Perl's regular expressions; it has the same |
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specification as pcretest, and so can be given identical input, except that |
specification as pcretest, and so can be given identical input, except that |
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input patterns can be followed only by Perl's lower case options. |
input patterns can be followed only by Perl's lower case options. The contents |
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of testinput and testinput3 meet this condition. |
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The data lines are processed as Perl strings, so if they contain $ or @ |
The data lines are processed as Perl strings, so if they contain $ or @ |
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characters, these have to be escaped. For this reason, all such characters in |
characters, these have to be escaped. For this reason, all such characters in |
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The testinput2 file is not suitable for feeding to Perltest, since it does |
The testinput2 file is not suitable for feeding to Perltest, since it does |
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make use of the special upper case options and escapes that pcretest uses to |
make use of the special upper case options and escapes that pcretest uses to |
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test additional features of PCRE. |
test some features of PCRE. It also contains malformed regular expressions, in |
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order to check that PCRE diagnoses them correctly. |
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Philip Hazel <ph10@cam.ac.uk> |
Philip Hazel <ph10@cam.ac.uk> |
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October 1997 |
September 1998 |