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revision 29 by nigel, Sat Feb 24 21:38:53 2007 UTC revision 39 by nigel, Sat Feb 24 21:39:13 2007 UTC
# Line 16  README file for PCRE (Perl-compatible re Line 16  README file for PCRE (Perl-compatible re
16  * possible to pass over a pointer to character tables built in the current    *  * possible to pass over a pointer to character tables built in the current    *
17  * locale by pcre_maketables(). To use the default tables, this new arguement  *  * locale by pcre_maketables(). To use the default tables, this new arguement  *
18  * should be passed as NULL.                                                   *  * should be passed as NULL.                                                   *
19    *                                                                             *
20    *           IMPORTANT FOR THOSE UPGRADING FROM VERSION 2.05                   *
21    *                                                                             *
22    * Yet another (and again I hope this really is the last) change has been made *
23    * to the API for the pcre_exec() function. An additional argument has been    *
24    * added to make it possible to start the match other than at the start of the *
25    * subject string. This is important if there are lookbehinds. The new man     *
26    * page has the details, but you just want to convert existing programs, all   *
27    * you need to do is to stick in a new fifth argument to pcre_exec(), with a   *
28    * value of zero. For example, change                                          *
29    *                                                                             *
30    *   pcre_exec(pattern, extra, subject, length, options, ovec, ovecsize)       *
31    * to                                                                          *
32    *   pcre_exec(pattern, extra, subject, length, 0, options, ovec, ovecsize)    *
33  *******************************************************************************  *******************************************************************************
34    
35    
36  The distribution should contain the following files:  The distribution should contain the following files:
37    
38    ChangeLog         log of changes to the code    ChangeLog         log of changes to the code
39    LICENCE           conditions for the use of PCRE    LICENCE           conditions for the use of PCRE
40    Makefile          for building PCRE    Makefile          for building PCRE in Unix systems
41    README            this file    README            this file
42    RunTest           a shell script for running tests    RunTest           a Unix shell script for running tests
43    Tech.Notes        notes on the encoding    Tech.Notes        notes on the encoding
44    pcre.3            man page for the functions    pcre.3            man page source for the functions
45    pcreposix.3       man page for the POSIX wrapper API    pcre.3.txt        plain text version
46      pcre.3.html       HTML version
47      pcreposix.3       man page source for the POSIX wrapper API
48      pcreposix.3.txt   plain text version
49      pcreposix.3.HTML  HTML version
50    dftables.c        auxiliary program for building chartables.c    dftables.c        auxiliary program for building chartables.c
51    get.c             )    get.c             )
52    maketables.c      )    maketables.c      )
# Line 38  The distribution should contain the foll Line 57  The distribution should contain the foll
57    pcreposix.h       header for the external POSIX wrapper API    pcreposix.h       header for the external POSIX wrapper API
58    internal.h        header for internal use    internal.h        header for internal use
59    pcretest.c        test program    pcretest.c        test program
60    pgrep.1           man page for pgrep    pgrep.1           man page source for pgrep
61      pgrep.1.txt       plain text version
62      pgrep.1.HTML      HTML version
63    pgrep.c           source of a grep utility that uses PCRE    pgrep.c           source of a grep utility that uses PCRE
64    perltest          Perl test program    perltest          Perl test program
65    testinput         test data, compatible with Perl 5.004 and 5.005    testinput1        test data, compatible with Perl 5.004 and 5.005
66    testinput2        test data for error messages and non-Perl things    testinput2        test data for error messages and non-Perl things
67    testinput3        test data, compatible with Perl 5.005    testinput3        test data, compatible with Perl 5.005
68    testinput4        test data for locale-specific tests    testinput4        test data for locale-specific tests
69    testoutput        test results corresponding to testinput    testoutput1       test results corresponding to testinput1
70    testoutput2       test results corresponding to testinput2    testoutput2       test results corresponding to testinput2
71    testoutput3       test results corresponding to testinput3    testoutput3       test results corresponding to testinput3
72    testoutput4       test results corresponding to testinput4    testoutput4       test results corresponding to testinput4
73      dll.mk            for Win32 DLL
74      pcre.def          ditto
75    
76  To build PCRE, edit Makefile for your system (it is a fairly simple make file,  To build PCRE on a Unix system, first edit Makefile for your system. It is a
77  and there are some comments at the top) and then run it. It builds two  fairly simple make file, and there are some comments near the top, after the
78  libraries called libpcre.a and libpcreposix.a, a test program called pcretest,  text "On a Unix system". Then run "make". It builds two libraries called
79  and the pgrep command.  libpcre.a and libpcreposix.a, a test program called pcretest, and the pgrep
80    command. You can use "make install" to copy these, and the public header file
81  To test PCRE, run the RunTest script in the pcre directory. This runs pcretest  pcre.h, to appropriate live directories on your system. These installation
82  on each of the testinput files in turn, and compares the output with the  directories are defined at the top of the Makefile, and you should edit them if
83    necessary.
84    
85    For a non-Unix system, read the comments at the top of Makefile, which give
86    some hints on what needs to be done. PCRE has been compiled on Windows systems
87    and on Macintoshes, but I don't know the details as I don't use those systems.
88    It should be straightforward to build PCRE on any system that has a Standard C
89    compiler.
90    
91    Some help in building a Win32 DLL of PCRE in GnuWin32 environments was
92    contributed by Paul.Sokolovsky@technologist.com. These environments are
93    Mingw32 (http://www.xraylith.wisc.edu/~khan/software/gnu-win32/) and
94    CygWin  (http://sourceware.cygnus.com/cygwin/). Paul comments:
95    
96      For CygWin, set CFLAGS=-mno-cygwin, and do 'make dll'. You'll get
97      pcre.dll (containing pcreposix also), libpcre.dll.a, and dynamically
98      linked pgrep and pcretest. If you have /bin/sh, run RunTest (three
99      main test go ok, locale not supported).
100    
101    To test PCRE, run the RunTest script in the pcre directory. This can also be
102    run by "make runtest". It runs the pcretest test program (which is documented
103    below) on each of the testinput files in turn, and compares the output with the
104  contents of the corresponding testoutput file. A file called testtry is used to  contents of the corresponding testoutput file. A file called testtry is used to
105  hold the output from pcretest (which is documented below).  hold the output from pcretest. To run pcretest on just one of the test files,
106    give its number as an argument to RunTest, for example:
 To run pcretest on just one of the test files, give its number as an argument  
 to RunTest, for example:  
107    
108    RunTest 3    RunTest 3
109    
110  The first and third test files can also be fed directly into the perltest  The first and third test files can also be fed directly into the perltest
111  program to check that Perl gives the same results. The third file requires the  script to check that Perl gives the same results. The third file requires the
112  additional features of release 5.005, which is why it is kept separate from the  additional features of release 5.005, which is why it is kept separate from the
113  main test input, which needs only Perl 5.004. In the long run, when 5.005 is  main test input, which needs only Perl 5.004. In the long run, when 5.005 is
114  widespread, these two test files may get amalgamated.  widespread, these two test files may get amalgamated.
# Line 88  output to say why. If running this test Line 130  output to say why. If running this test
130  in the comparison output, it means that locale is not available on your system,  in the comparison output, it means that locale is not available on your system,
131  despite being listed by "locale". This does not mean that PCRE is broken.  despite being listed by "locale". This does not mean that PCRE is broken.
132    
 To install PCRE, copy libpcre.a to any suitable library directory (e.g.  
 /usr/local/lib), pcre.h to any suitable include directory (e.g.  
 /usr/local/include), and pcre.3 to any suitable man directory (e.g.  
 /usr/local/man/man3).  
   
 To install the pgrep command, copy it to any suitable binary directory, (e.g.  
 /usr/local/bin) and pgrep.1 to any suitable man directory (e.g.  
 /usr/local/man/man1).  
   
133  PCRE has its own native API, but a set of "wrapper" functions that are based on  PCRE has its own native API, but a set of "wrapper" functions that are based on
134  the POSIX API are also supplied in the library libpcreposix.a. Note that this  the POSIX API are also supplied in the library libpcreposix.a. Note that this
135  just provides a POSIX calling interface to PCRE: the regular expressions  just provides a POSIX calling interface to PCRE: the regular expressions
# Line 112  Character tables Line 145  Character tables
145    
146  PCRE uses four tables for manipulating and identifying characters. The final  PCRE uses four tables for manipulating and identifying characters. The final
147  argument of the pcre_compile() function is a pointer to a block of memory  argument of the pcre_compile() function is a pointer to a block of memory
148  containing the concatenated tables. A call to pcre_maketables() is used to  containing the concatenated tables. A call to pcre_maketables() can be used to
149  generate a set of tables in the current locale. However, if the final argument  generate a set of tables in the current locale. If the final argument for
150  is passed as NULL, a set of default tables that is built into the binary is  pcre_compile() is passed as NULL, a set of default tables that is built into
151  used.  the binary is used.
152    
153  The source file called chartables.c contains the default set of tables. This is  The source file called chartables.c contains the default set of tables. This is
154  not supplied in the distribution, but is built by the program dftables  not supplied in the distribution, but is built by the program dftables
155  (compiled from dftables.c), which uses the ANSI C character handling functions  (compiled from dftables.c), which uses the ANSI C character handling functions
156  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table  such as isalnum(), isalpha(), isupper(), islower(), etc. to build the table
157  sources. This means that the default C locale set your system will control the  sources. This means that the default C locale which is set for your system will
158  contents of the tables. You can change the default tables by editing  control the contents of these default tables. You can change the default tables
159  chartables.c and then re-building PCRE. If you do this, you should probably  by editing chartables.c and then re-building PCRE. If you do this, you should
160  also edit Makefile to ensure that the file doesn't ever get re-generated.  probably also edit Makefile to ensure that the file doesn't ever get
161    re-generated.
162    
163  The first two 256-byte tables provide lower casing and case flipping functions,  The first two 256-byte tables provide lower casing and case flipping functions,
164  respectively. The next table consists of three 32-byte bit maps which identify  respectively. The next table consists of three 32-byte bit maps which identify
# Line 178  example, Line 212  example,
212    
213    /abc/\    /abc/\
214    
215  then a backslash is added to the end of the pattern. This provides a way of  then a backslash is added to the end of the pattern. This is done to provide a
216  testing the error condition that arises if a pattern finishes with a backslash,  way of testing the error condition that arises if a pattern finishes with a
217  because  backslash, because
218    
219    /abc\/    /abc\/
220    
# Line 188  is interpreted as the first line of a pa Line 222  is interpreted as the first line of a pa
222  pcretest to read the next line as a continuation of the regular expression.  pcretest to read the next line as a continuation of the regular expression.
223    
224  The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,  The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,
225  PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. These  PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For
226  options have the same effect as they do in Perl.  example:
227    
228      /caseless/i
229    
230  There are also some upper case options that do not match Perl options: /A, /E,  These modifier letters have the same effect as they do in Perl. There are
231  and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.  others which set PCRE options that do not correspond to anything in Perl: /A,
232    /E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.
233    
234    Searching for all possible matches within each subject string can be requested
235    by the /g or /G modifier. After finding a match, PCRE is called again to search
236    the remainder of the subject string. The difference between /g and /G is that
237    the former uses the startoffset argument to pcre_exec() to start searching at
238    a new point within the entire string (which is in effect what Perl does),
239    whereas the latter passes over a shortened substring. This makes a difference
240    to the matching process if the pattern begins with a lookbehind assertion
241    (including \b or \B).
242    
243    If any call to pcre_exec() in a /g or /G sequence matches an empty string, the
244    next call is done with the PCRE_NOTEMPTY flag set so that it cannot match an
245    empty string again. This imitates the way Perl handles such cases when using
246    the /g modifier or the split() function.
247    
248    There are a number of other modifiers for controlling the way pcretest
249    operates.
250    
251    The /+ modifier requests that as well as outputting the substring that matched
252    the entire pattern, pcretest should in addition output the remainder of the
253    subject string. This is useful for tests where the subject contains multiple
254    copies of the same substring.
255    
256  The /L option must be followed directly by the name of a locale, for example,  The /L modifier must be followed directly by the name of a locale, for example,
257    
258    /pattern/Lfr    /pattern/Lfr
259    
260  For this reason, it must be the last option letter. The given locale is set,  For this reason, it must be the last modifier letter. The given locale is set,
261  pcre_maketables() is called to build a set of character tables for the locale,  pcre_maketables() is called to build a set of character tables for the locale,
262  and this is then passed to pcre_compile() when compiling the regular  and this is then passed to pcre_compile() when compiling the regular
263  expression. Without an /L option, NULL is passed as the tables pointer; that  expression. Without an /L modifier, NULL is passed as the tables pointer; that
264  is, /L applies only to the expression on which it appears.  is, /L applies only to the expression on which it appears.
265    
266  The /I option requests that pcretest output information about the compiled  The /I modifier requests that pcretest output information about the compiled
267  expression (whether it is anchored, has a fixed first character, and so on). It  expression (whether it is anchored, has a fixed first character, and so on). It
268  does this by calling pcre_info() after compiling an expression, and outputting  does this by calling pcre_info() after compiling an expression, and outputting
269  the information it gets back. If the pattern is studied, the results of that  the information it gets back. If the pattern is studied, the results of that
270  are also output.  are also output.
271    
272  The /D option is a PCRE debugging feature, which also assumes /I. It causes the  The /D modifier is a PCRE debugging feature, which also assumes /I. It causes
273  internal form of compiled regular expressions to be output after compilation.  the internal form of compiled regular expressions to be output after
274    compilation.
275    
276  The /S option causes pcre_study() to be called after the expression has been  The /S modifier causes pcre_study() to be called after the expression has been
277  compiled, and the results used when the expression is matched.  compiled, and the results used when the expression is matched.
278    
279  Finally, the /P option causes pcretest to call PCRE via the POSIX wrapper API  The /M modifier causes the size of memory block used to hold the compiled
280  rather than its native API. When this is done, all other options except /i and  pattern to be output.
281  /m are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is set if /m  
282  is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, and  Finally, the /P modifier causes pcretest to call PCRE via the POSIX wrapper API
283  PCRE_DOTALL unless REG_NEWLINE is set.  rather than its native API. When this is done, all other modifiers except /i,
284    /m, and /+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is
285    set if /m is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always,
286    and PCRE_DOTALL unless REG_NEWLINE is set.
287    
288  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
289  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:
# Line 243  is removed, and it is then scanned for \ Line 306  is removed, and it is then scanned for \
306    \Gdd   call pcre_get_substring() for substring dd after a successful match    \Gdd   call pcre_get_substring() for substring dd after a successful match
307             (any decimal number less than 32)             (any decimal number less than 32)
308    \L     call pcre_get_substringlist() after a successful match    \L     call pcre_get_substringlist() after a successful match
309      \N     pass the PCRE_NOTEMPTY option to pcre_exec()
310    \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
311             (any number of decimal digits)             (any number of decimal digits)
312    \Z     pass the PCRE_NOTEOL option to pcre_exec()    \Z     pass the PCRE_NOTEOL option to pcre_exec()
# Line 260  pcre_exec() returns, starting with numbe Line 324  pcre_exec() returns, starting with numbe
324  whole pattern. Here is an example of an interactive pcretest run.  whole pattern. Here is an example of an interactive pcretest run.
325    
326    $ pcretest    $ pcretest
327    Testing Perl-Compatible Regular Expressions    PCRE version 2.06 08-Jun-1999
   PCRE version 0.90 08-Sep-1997  
328    
329      re> /^abc(\d+)/      re> /^abc(\d+)/
330    data> abc123    data> abc123
331      0: abc123     0: abc123
332      1: 123     1: 123
333    data> xyz    data> xyz
334    No match    No match
335    
336    If the strings contain any non-printing characters, they are output as \0x
337    escapes. If the pattern has the /+ modifier, then the output for substring 0 is
338    followed by the the rest of the subject string, identified by "0+" like this:
339    
340        re> /cat/+
341      data> cataract
342       0: cat
343       0+ aract
344    
345    If the pattern has the /g or /G modifier, the results of successive matching
346    attempts are output in sequence, like this:
347    
348        re> /\Bi(\w\w)/g
349      data> Mississippi
350       0: iss
351       1: ss
352       0: iss
353       1: ss
354       0: ipp
355       1: pp
356    
357    "No match" is output only if the first match attempt fails.
358    
359  If any of \C, \G, or \L are present in a data line that is successfully  If any of \C, \G, or \L are present in a data line that is successfully
360  matched, the substrings extracted by the convenience functions are output with  matched, the substrings extracted by the convenience functions are output with
361  C, G, or L after the string number instead of a colon. This is in addition to  C, G, or L after the string number instead of a colon. This is in addition to
# Line 291  If the option -i is given to pcretest, i Line 377  If the option -i is given to pcretest, i
377  regular expression: information about the compiled pattern is given after  regular expression: information about the compiled pattern is given after
378  compilation.  compilation.
379    
380  If the option -s is given to pcretest, it outputs the size of each compiled  If the option -m is given to pcretest, it outputs the size of each compiled
381  pattern after it has been compiled.  pattern after it has been compiled. It is equivalent to adding /M to each
382    regular expression. For compatibility with earlier versions of pcretest, -s is
383    a synonym for -m.
384    
385  If the -t option is given, each compile, study, and match is run 20000 times  If the -t option is given, each compile, study, and match is run 20000 times
386  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
# Line 308  The perltest program Line 396  The perltest program
396    
397  The perltest program tests Perl's regular expressions; it has the same  The perltest program tests Perl's regular expressions; it has the same
398  specification as pcretest, and so can be given identical input, except that  specification as pcretest, and so can be given identical input, except that
399  input patterns can be followed only by Perl's lower case options. The contents  input patterns can be followed only by Perl's lower case modifiers. The
400  of testinput and testinput3 meet this condition.  contents of testinput1 and testinput3 meet this condition.
401    
402  The data lines are processed as Perl strings, so if they contain $ or @  The data lines are processed as Perl double-quoted strings, so if they contain
403  characters, these have to be escaped. For this reason, all such characters in  " \ $ or @ characters, these have to be escaped. For this reason, all such
404  the testinput file are escaped so that it can be used for perltest as well as  characters in testinput1 and testinput3 are escaped so that they can be used
405  for pcretest, and the special upper case options such as /A that pcretest  for perltest as well as for pcretest, and the special upper case modifiers such
406  recognizes are not used in this file. The output should be identical, apart  as /A that pcretest recognizes are not used in these files. The output should
407  from the initial identifying banner.  be identical, apart from the initial identifying banner.
408    
409  The testinput2 and testinput4 files are not suitable for feeding to Perltest,  The testinput2 and testinput4 files are not suitable for feeding to perltest,
410  since they do make use of the special upper case options and escapes that  since they do make use of the special upper case modifiers and escapes that
411  pcretest uses to test some features of PCRE. The first of these files also  pcretest uses to test some features of PCRE. The first of these files also
412  contains malformed regular expressions, in order to check that PCRE diagnoses  contains malformed regular expressions, in order to check that PCRE diagnoses
413  them correctly.  them correctly.
414    
415  Philip Hazel <ph10@cam.ac.uk>  Philip Hazel <ph10@cam.ac.uk>
416  February 1999  July 1999

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