-This file contains the PCRE man page that described the pcretest program. Note
-that not all of the features of PCRE are available in the limited version that
+This file contains the PCRE man page that described the pcretest program. Note
+that not all of the features of PCRE are available in the limited version that
is built with Exim.
-------------------------------------------------------------------------------
PCRETEST(1) PCRETEST(1)
-
NAME
pcretest - a program for testing Perl-compatible regular expressions.
+
SYNOPSIS
- pcretest [-C] [-d] [-i] [-m] [-o osize] [-p] [-t] [source]
+ pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]
[destination]
pcretest was written as a test program for the PCRE regular expression
able information about the optional features that are
included, and then exit.
- -d Behave as if each regex had the /D (debug) modifier; the
+ -d Behave as if each regex has the /D (debug) modifier; the
internal form is output after compilation.
- -i Behave as if each regex had the /I modifier; information
+ -dfa Behave as if each data line contains the \D escape sequence;
+ this causes the alternative matching function,
+ pcre_dfa_exec(), to be used instead of the standard
+ pcre_exec() function (more detail is given below).
+
+ -i Behave as if each regex has the /I modifier; information
about the compiled pattern is given after compilation.
- -m Output the size of each compiled pattern after it has been
- compiled. This is equivalent to adding /M to each regular
- expression. For compatibility with earlier versions of
+ -m Output the size of each compiled pattern after it has been
+ compiled. This is equivalent to adding /M to each regular
+ expression. For compatibility with earlier versions of
pcretest, -s is a synonym for -m.
- -o osize Set the number of elements in the output vector that is used
- when calling pcre_exec() to be osize. The default value is
+ -o osize Set the number of elements in the output vector that is used
+ when calling pcre_exec() to be osize. The default value is
45, which is enough for 14 capturing subexpressions. The vec-
- tor size can be changed for individual matching calls by
+ tor size can be changed for individual matching calls by
including \O in the data line (see below).
- -p Behave as if each regex has /P modifier; the POSIX wrapper
- API is used to call PCRE. None of the other options has any
- effect when -p is set.
+ -p Behave as if each regex has the /P modifier; the POSIX wrap-
+ per API is used to call PCRE. None of the other options has
+ any effect when -p is set.
- -t Run each compile, study, and match many times with a timer,
- and output resulting time per compile or match (in millisec-
- onds). Do not set -m with -t, because you will then get the
- size output a zillion times, and the timing will be dis-
+ -t Run each compile, study, and match many times with a timer,
+ and output resulting time per compile or match (in millisec-
+ onds). Do not set -m with -t, because you will then get the
+ size output a zillion times, and the timing will be dis-
torted.
DESCRIPTION
- If pcretest is given two filename arguments, it reads from the first
+ If pcretest is given two filename arguments, it reads from the first
and writes to the second. If it is given only one filename argument, it
- reads from that file and writes to stdout. Otherwise, it reads from
- stdin and writes to stdout, and prompts for each line of input, using
+ reads from that file and writes to stdout. Otherwise, it reads from
+ stdin and writes to stdout, and prompts for each line of input, using
"re>" to prompt for regular expressions, and "data>" to prompt for data
lines.
The program handles any number of sets of input on a single input file.
- Each set starts with a regular expression, and continues with any num-
+ Each set starts with a regular expression, and continues with any num-
ber of data lines to be matched against the pattern.
- Each data line is matched separately and independently. If you want to
- do multiple-line matches, you have to use the \n escape sequence in a
- single line of input to encode the newline characters. The maximum
+ Each data line is matched separately and independently. If you want to
+ do multiple-line matches, you have to use the \n escape sequence in a
+ single line of input to encode the newline characters. The maximum
length of data line is 30,000 characters.
- An empty line signals the end of the data lines, at which point a new
- regular expression is read. The regular expressions are given enclosed
+ An empty line signals the end of the data lines, at which point a new
+ regular expression is read. The regular expressions are given enclosed
in any non-alphanumeric delimiters other than backslash, for example
/(a|bc)x+yz/
- White space before the initial delimiter is ignored. A regular expres-
- sion may be continued over several input lines, in which case the new-
- line characters are included within it. It is possible to include the
+ White space before the initial delimiter is ignored. A regular expres-
+ sion may be continued over several input lines, in which case the new-
+ line characters are included within it. It is possible to include the
delimiter within the pattern by escaping it, for example
/abc\/def/
- If you do so, the escape and the delimiter form part of the pattern,
- but since delimiters are always non-alphanumeric, this does not affect
- its interpretation. If the terminating delimiter is immediately fol-
+ If you do so, the escape and the delimiter form part of the pattern,
+ but since delimiters are always non-alphanumeric, this does not affect
+ its interpretation. If the terminating delimiter is immediately fol-
lowed by a backslash, for example,
/abc/\
- then a backslash is added to the end of the pattern. This is done to
- provide a way of testing the error condition that arises if a pattern
+ then a backslash is added to the end of the pattern. This is done to
+ provide a way of testing the error condition that arises if a pattern
finishes with a backslash, because
/abc\/
- is interpreted as the first line of a pattern that starts with "abc/",
+ is interpreted as the first line of a pattern that starts with "abc/",
causing pcretest to read the next line as a continuation of the regular
expression.
PATTERN MODIFIERS
- A pattern may be followed by any number of modifiers, which are mostly
- single characters. Following Perl usage, these are referred to below
- as, for example, "the /i modifier", even though the delimiter of the
- pattern need not always be a slash, and no slash is used when writing
- modifiers. Whitespace may appear between the final pattern delimiter
+ A pattern may be followed by any number of modifiers, which are mostly
+ single characters. Following Perl usage, these are referred to below
+ as, for example, "the /i modifier", even though the delimiter of the
+ pattern need not always be a slash, and no slash is used when writing
+ modifiers. Whitespace may appear between the final pattern delimiter
and the first modifier, and between the modifiers themselves.
The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
- PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com-
- pile() is called. These four modifier letters have the same effect as
+ PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com-
+ pile() is called. These four modifier letters have the same effect as
they do in Perl. For example:
/caseless/i
/A PCRE_ANCHORED
/C PCRE_AUTO_CALLOUT
/E PCRE_DOLLAR_ENDONLY
+ /f PCRE_FIRSTLINE
/N PCRE_NO_AUTO_CAPTURE
/U PCRE_UNGREEDY
/X PCRE_EXTRA
- Searching for all possible matches within each subject string can be
- requested by the /g or /G modifier. After finding a match, PCRE is
+ Searching for all possible matches within each subject string can be
+ requested by the /g or /G modifier. After finding a match, PCRE is
called again to search the remainder of the subject string. The differ-
ence between /g and /G is that the former uses the startoffset argument
- to pcre_exec() to start searching at a new point within the entire
- string (which is in effect what Perl does), whereas the latter passes
- over a shortened substring. This makes a difference to the matching
+ to pcre_exec() to start searching at a new point within the entire
+ string (which is in effect what Perl does), whereas the latter passes
+ over a shortened substring. This makes a difference to the matching
process if the pattern begins with a lookbehind assertion (including \b
or \B).
- If any call to pcre_exec() in a /g or /G sequence matches an empty
- string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
- flags set in order to search for another, non-empty, match at the same
- point. If this second match fails, the start offset is advanced by
- one, and the normal match is retried. This imitates the way Perl han-
+ If any call to pcre_exec() in a /g or /G sequence matches an empty
+ string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
+ flags set in order to search for another, non-empty, match at the same
+ point. If this second match fails, the start offset is advanced by
+ one, and the normal match is retried. This imitates the way Perl han-
dles such cases when using the /g modifier or the split() function.
There are yet more modifiers for controlling the way pcretest operates.
- The /+ modifier requests that as well as outputting the substring that
- matched the entire pattern, pcretest should in addition output the
- remainder of the subject string. This is useful for tests where the
+ The /+ modifier requests that as well as outputting the substring that
+ matched the entire pattern, pcretest 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 /L modifier must be followed directly by the name of a locale, for
+ The /L modifier must be followed directly by the name of a locale, for
example,
/pattern/Lfr_FR
For this reason, it must be the last modifier. The given locale is set,
- pcre_maketables() is called to build a set of character tables for the
- locale, and this is then passed to pcre_compile() when compiling the
- regular expression. Without an /L modifier, NULL is passed as the
- tables pointer; that is, /L applies only to the expression on which it
+ pcre_maketables() is called to build a set of character tables for the
+ locale, and this is then passed to pcre_compile() when compiling the
+ regular expression. Without an /L modifier, NULL is passed as the
+ tables pointer; that is, /L applies only to the expression on which it
appears.
- The /I modifier requests that pcretest output information about the
- compiled pattern (whether it is anchored, has a fixed first character,
- and so on). It does this by calling pcre_fullinfo() after compiling a
- pattern. If the pattern is studied, the results of that are also out-
+ The /I modifier requests that pcretest output information about the
+ compiled pattern (whether it is anchored, has a fixed first character,
+ and so on). It does this by calling pcre_fullinfo() after compiling a
+ pattern. If the pattern is studied, the results of that are also out-
put.
The /D modifier is a PCRE debugging feature, which also assumes /I. It
- causes the internal form of compiled regular expressions to be output
+ causes the internal form of compiled regular expressions to be output
after compilation. If the pattern was studied, the information returned
is also output.
The /F modifier causes pcretest to flip the byte order of the fields in
- the compiled pattern that contain 2-byte and 4-byte numbers. This
- facility is for testing the feature in PCRE that allows it to execute
+ the compiled pattern that contain 2-byte and 4-byte numbers. This
+ facility is for testing the feature in PCRE that allows it to execute
patterns that were compiled on a host with a different endianness. This
- feature is not available when the POSIX interface to PCRE is being
- used, that is, when the /P pattern modifier is specified. See also the
+ feature is not available when the POSIX interface to PCRE is being
+ used, that is, when the /P pattern modifier is specified. See also the
section about saving and reloading compiled patterns below.
- The /S modifier causes pcre_study() to be called after the expression
+ The /S modifier causes pcre_study() to be called after the expression
has been compiled, and the results used when the expression is matched.
- The /M modifier causes the size of memory block used to hold the com-
+ The /M modifier causes the size of memory block used to hold the com-
piled pattern to be output.
- The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
- rather than its native API. When this is done, all other modifiers
- except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
- and REG_NEWLINE is set if /m is present. The wrapper functions force
- PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
+ The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
+ rather than its native API. When this is done, all other modifiers
+ except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
+ and REG_NEWLINE is set if /m is present. The wrapper functions force
+ PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
- The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
- set. This turns on support for UTF-8 character handling in PCRE, pro-
- vided that it was compiled with this support enabled. This modifier
+ The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
+ set. This turns on support for UTF-8 character handling in PCRE, pro-
+ vided that it was compiled with this support enabled. This modifier
also causes any non-printing characters in output strings to be printed
using the \x{hh...} notation if they are valid UTF-8 sequences.
- If the /? modifier is used with /8, it causes pcretest to call
- pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the
+ If the /? modifier is used with /8, it causes pcretest to call
+ pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the
checking of the string for UTF-8 validity.
DATA LINES
- Before each data line is passed to pcre_exec(), leading and trailing
- whitespace is removed, and it is then scanned for \ escapes. Some of
- these are pretty esoteric features, intended for checking out some of
- the more complicated features of PCRE. If you are just testing "ordi-
- nary" regular expressions, you probably don't need any of these. The
+ Before each data line is passed to pcre_exec(), leading and trailing
+ whitespace is removed, and it is then scanned for \ escapes. Some of
+ these are pretty esoteric features, intended for checking out some of
+ the more complicated features of PCRE. If you are just testing "ordi-
+ nary" regular expressions, you probably don't need any of these. The
following escapes are recognized:
\a alarm (= BEL)
reached for the nth time
\C*n pass the number n (may be negative) as callout
data; this is used as the callout return value
+ \D use the pcre_dfa_exec() match function
+ \F only shortest match for pcre_dfa_exec()
\Gdd call pcre_get_substring() for substring dd
after a successful match (number less than 32)
\Gname call pcre_get_named_substring() for substring
\Odd set the size of the output vector passed to
pcre_exec() to dd (any number of digits)
\P pass the PCRE_PARTIAL option to pcre_exec()
+ or pcre_dfa_exec()
+ \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
\S output details of memory get/free calls during matching
\Z pass the PCRE_NOTEOL option to pcre_exec()
\? pass the PCRE_NO_UTF8_CHECK option to
\>dd start the match at offset dd (any number of digits);
this sets the startoffset argument for pcre_exec()
- A backslash followed by anything else just escapes the anything else.
- If the very last character is a backslash, it is ignored. This gives a
- way of passing an empty line as data, since a real empty line termi-
+ A backslash followed by anything else just escapes the anything else.
+ If the very last character is a backslash, it is ignored. This gives a
+ way of passing an empty line as data, since a real empty line termi-
nates the data input.
- If \M is present, pcretest calls pcre_exec() several times, with dif-
- ferent values in the match_limit field of the pcre_extra data struc-
- ture, until it finds the minimum number that is needed for pcre_exec()
- to complete. This number is a measure of the amount of recursion and
- backtracking that takes place, and checking it out can be instructive.
- For most simple matches, the number is quite small, but for patterns
- with very large numbers of matching possibilities, it can become large
+ If \M is present, pcretest calls pcre_exec() several times, with dif-
+ ferent values in the match_limit field of the pcre_extra data struc-
+ ture, until it finds the minimum number that is needed for pcre_exec()
+ to complete. This number is a measure of the amount of recursion and
+ backtracking that takes place, and checking it out can be instructive.
+ For most simple matches, the number is quite small, but for patterns
+ with very large numbers of matching possibilities, it can become large
very quickly with increasing length of subject string.
- When \O is used, the value specified may be higher or lower than the
+ When \O is used, the value specified may be higher or lower than the
size set by the -O command line option (or defaulted to 45); \O applies
only to the call of pcre_exec() for the line in which it appears.
- If the /P modifier was present on the pattern, causing the POSIX wrap-
- per API to be used, only \B and \Z have any effect, causing REG_NOTBOL
+ If the /P modifier was present on the pattern, causing the POSIX wrap-
+ per API to be used, only \B and \Z have any effect, causing REG_NOTBOL
and REG_NOTEOL to be passed to regexec() respectively.
- The use of \x{hh...} to represent UTF-8 characters is not dependent on
- the use of the /8 modifier on the pattern. It is recognized always.
- There may be any number of hexadecimal digits inside the braces. The
- result is from one to six bytes, encoded according to the UTF-8 rules.
+ The use of \x{hh...} to represent UTF-8 characters is not dependent on
+ the use of the /8 modifier on the pattern. It is recognized always.
+ There may be any number of hexadecimal digits inside the braces. The
+ result is from one to six bytes, encoded according to the UTF-8 rules.
+
+
+THE ALTERNATIVE MATCHING FUNCTION
+
+ By default, pcretest uses the standard PCRE matching function,
+ pcre_exec() to match each data line. From release 6.0, PCRE supports an
+ alternative matching function, pcre_dfa_test(), which operates in a
+ different way, and has some restrictions. The differences between the
+ two functions are described in the pcrematching documentation.
+ If a data line contains the \D escape sequence, or if the command line
+ contains the -dfa option, the alternative matching function is called.
+ This function finds all possible matches at a given point. If, however,
+ the \F escape sequence is present in the data line, it stops after the
+ first match is found. This is always the shortest possible match.
-OUTPUT FROM PCRETEST
+
+DEFAULT OUTPUT FROM PCRETEST
+
+ This section describes the output when the normal matching function,
+ pcre_exec(), is being used.
When a match succeeds, pcretest outputs the list of captured substrings
that pcre_exec() returns, starting with number 0 for the string that
lines can be included in data by means of the \n escape.
+OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
+
+ When the alternative matching function, pcre_dfa_exec(), is used (by
+ means of the \D escape sequence or the -dfa command line option), the
+ output consists of a list of all the matches that start at the first
+ point in the subject where there is at least one match. For example:
+
+ re> /(tang|tangerine|tan)/
+ data> yellow tangerine\D
+ 0: tangerine
+ 1: tang
+ 2: tan
+
+ (Using the normal matching function on this data finds only "tang".)
+ The longest matching string is always given first (and numbered zero).
+
+ If /gP is present on the pattern, the search for further matches
+ resumes at the end of the longest match. For example:
+
+ re> /(tang|tangerine|tan)/g
+ data> yellow tangerine and tangy sultana\D
+ 0: tangerine
+ 1: tang
+ 2: tan
+ 0: tang
+ 1: tan
+ 0: tan
+
+ Since the matching function does not support substring capture, the
+ escape sequences that are concerned with captured substrings are not
+ relevant.
+
+
+RESTARTING AFTER A PARTIAL MATCH
+
+ When the alternative matching function has given the PCRE_ERROR_PARTIAL
+ return, indicating that the subject partially matched the pattern, you
+ can restart the match with additional subject data by means of the \R
+ escape sequence. For example:
+
+ re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
+ data> 23ja\P\D
+ Partial match: 23ja
+ data> n05\R\D
+ 0: n05
+
+ For further information about partial matching, see the pcrepartial
+ documentation.
+
+
CALLOUTS
If the pattern contains any callout requests, pcretest's callout func-
- tion is called during matching. By default, it 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, the output
+ tion is called during matching. This works with both matching func-
+ tions. By default, the called function displays the callout number, the
+ start and current positions in the text at the callout time, and the
+ next pattern item to be tested. For example, the output
--->pqrabcdef
0 ^ ^ \d
- indicates that callout number 0 occurred for a match attempt starting
- at the fourth character of the subject string, when the pointer was at
- the seventh character of the data, and when the next pattern item was
- \d. Just one circumflex is output if the start and current positions
+ indicates that callout number 0 occurred for a match attempt starting
+ at the fourth character of the subject string, when the pointer was at
+ the seventh character of the data, and when the next pattern item was
+ \d. Just one circumflex is output if the start and current positions
are the same.
Callouts numbered 255 are assumed to be automatic callouts, inserted as
- a result of the /C pattern modifier. In this case, instead of showing
- the callout number, the offset in the pattern, preceded by a plus, is
+ a result of the /C pattern modifier. In this case, instead of showing
+ the callout number, the offset in the pattern, preceded by a plus, is
output. For example:
re> /\d?[A-E]\*/C
+10 ^ ^
0: E*
- The callout function in pcretest returns zero (carry on matching) by
- default, but you can use an \C item in a data line (as described above)
+ The callout function in pcretest returns zero (carry on matching) by
+ default, but you can use a \C item in a data line (as described above)
to change this.
- Inserting callouts can be helpful when using pcretest to check compli-
- cated regular expressions. For further information about callouts, see
+ Inserting callouts can be helpful when using pcretest to check compli-
+ cated regular expressions. For further information about callouts, see
the pcrecallout documentation.
SAVING AND RELOADING COMPILED PATTERNS
- The facilities described in this section are not available when the
+ The facilities described in this section are not available when the
POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
ifier is specified.
When the POSIX interface is not in use, you can cause pcretest to write
- a compiled pattern to a file, by following the modifiers with > and a
+ a compiled pattern to a file, by following the modifiers with > and a
file name. For example:
/pattern/im >/some/file
- See the pcreprecompile documentation for a discussion about saving and
+ See the pcreprecompile documentation for a discussion about saving and
re-using compiled patterns.
- The data that is written is binary. The first eight bytes are the
- length of the compiled pattern data followed by the length of the
- optional study data, each written as four bytes in big-endian order
- (most significant byte first). If there is no study data (either the
+ The data that is written is binary. The first eight bytes are the
+ length of the compiled pattern data followed by the length of the
+ optional study data, each written as four bytes in big-endian order
+ (most significant byte first). If there is no study data (either the
pattern was not studied, or studying did not return any data), the sec-
- ond length is zero. The lengths are followed by an exact copy of the
+ ond length is zero. The lengths are followed by an exact copy of the
compiled pattern. If there is additional study data, this follows imme-
- diately after the compiled pattern. After writing the file, pcretest
+ diately after the compiled pattern. After writing the file, pcretest
expects to read a new pattern.
A saved pattern can be reloaded into pcretest by specifing < and a file
- name instead of a pattern. The name of the file must not contain a <
- character, as otherwise pcretest will interpret the line as a pattern
+ name instead of a pattern. The name of the file must not contain a <
+ character, as otherwise pcretest will interpret the line as a pattern
delimited by < characters. For example:
re> </some/file
Compiled regex loaded from /some/file
No study data
- When the pattern has been loaded, pcretest proceeds to read data lines
+ When the pattern has been loaded, pcretest proceeds to read data lines
in the usual way.
- You can copy a file written by pcretest to a different host and reload
- it there, even if the new host has opposite endianness to the one on
- which the pattern was compiled. For example, you can compile on an i86
+ You can copy a file written by pcretest to a different host and reload
+ it there, even if the new host has opposite endianness to the one on
+ which the pattern was compiled. For example, you can compile on an i86
machine and run on a SPARC machine.
- File names for saving and reloading can be absolute or relative, but
- note that the shell facility of expanding a file name that starts with
+ File names for saving and reloading can be absolute or relative, but
+ note that the shell facility of expanding a file name that starts with
a tilde (~) is not available.
- The ability to save and reload files in pcretest is intended for test-
- ing and experimentation. It is not intended for production use because
- only a single pattern can be written to a file. Furthermore, there is
- no facility for supplying custom character tables for use with a
- reloaded pattern. If the original pattern was compiled with custom
- tables, an attempt to match a subject string using a reloaded pattern
- is likely to cause pcretest to crash. Finally, if you attempt to load
+ The ability to save and reload files in pcretest is intended for test-
+ ing and experimentation. It is not intended for production use because
+ only a single pattern can be written to a file. Furthermore, there is
+ no facility for supplying custom character tables for use with a
+ reloaded pattern. If the original pattern was compiled with custom
+ tables, an attempt to match a subject string using a reloaded pattern
+ is likely to cause pcretest to crash. Finally, if you attempt to load
a file that is not in the correct format, the result is undefined.
AUTHOR
- Philip Hazel <ph10@cam.ac.uk>
+ Philip Hazel
University Computing Service,
Cambridge CB2 3QG, England.
-Last updated: 10 September 2004
-Copyright (c) 1997-2004 University of Cambridge.
+Last updated: 28 February 2005
+Copyright (c) 1997-2005 University of Cambridge.
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