-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]
- [destination]
+ pcretest [options] [source] [destination]
pcretest was written as a test program for the PCRE regular expression
library itself, but it can also be used for experimenting with regular
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.
+
+ -q Do not output the version number of pcretest at the start of
+ execution.
- -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-
+ -S size On Unix-like systems, set the size of the runtime stack to
+ size megabytes.
+
+ -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
- length of data line is 30,000 characters.
+ Each data line is matched separately and independently. If you want to
+ do multi-line matches, you have to use the \n escape sequence (or \r or
+ \r\n, depending on the newline setting) in a single line of input to
+ encode the newline characters. There is no limit on the length of data
+ lines; the input buffer is automatically extended if it is too small.
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
+ in any non-alphanumeric delimiters other than backslash, for example:
/(a|bc)x+yz/
The following table shows additional modifiers for setting PCRE options
that do not correspond to anything in Perl:
- /A PCRE_ANCHORED
- /C PCRE_AUTO_CALLOUT
- /E PCRE_DOLLAR_ENDONLY
- /N PCRE_NO_AUTO_CAPTURE
- /U PCRE_UNGREEDY
- /X PCRE_EXTRA
+ /A PCRE_ANCHORED
+ /C PCRE_AUTO_CALLOUT
+ /E PCRE_DOLLAR_ENDONLY
+ /f PCRE_FIRSTLINE
+ /J PCRE_DUPNAMES
+ /N PCRE_NO_AUTO_CAPTURE
+ /U PCRE_UNGREEDY
+ /X PCRE_EXTRA
+ /<cr> PCRE_NEWLINE_CR
+ /<lf> PCRE_NEWLINE_LF
+ /<crlf> PCRE_NEWLINE_CRLF
+
+ Those specifying line endings are literal strings as shown. Details of
+ the meanings of these PCRE options are given in the pcreapi documenta-
+ tion.
+
+ Finding all matches in a string
Searching for all possible matches within each subject string can be
requested by the /g or /G modifier. After finding a match, PCRE is
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.
+ Other modifiers
+
There are yet more modifiers for controlling the way pcretest operates.
The /+ modifier requests that as well as outputting the substring that
\e escape
\f formfeed
\n newline
+ \qdd set the PCRE_MATCH_LIMIT limit to dd
+ (any number of digits)
\r carriage return
\t tab
\v vertical tab
\x{hh...} hexadecimal character, any number of digits
in UTF-8 mode
\A pass the PCRE_ANCHORED option to pcre_exec()
+ or pcre_dfa_exec()
\B pass the PCRE_NOTBOL option to pcre_exec()
+ or pcre_dfa_exec()
\Cdd call pcre_copy_substring() for substring dd
after a successful match (number less than 32)
\Cname call pcre_copy_named_substring() for substring
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
ated by next non-alphanumeric character)
\L call pcre_get_substringlist() after a
successful match
- \M discover the minimum MATCH_LIMIT setting
+ \M discover the minimum MATCH_LIMIT and
+ MATCH_LIMIT_RECURSION settings
\N pass the PCRE_NOTEMPTY option to pcre_exec()
+ or pcre_dfa_exec()
\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()
+ \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
+ (any number of digits)
+ \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()
+ or pcre_dfa_exec()
\? pass the PCRE_NO_UTF8_CHECK option to
- pcre_exec()
+ pcre_exec() or pcre_dfa_exec()
\>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-
- 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
- very quickly with increasing length of subject string.
+ or pcre_dfa_exec()
+ \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec()
+ or pcre_dfa_exec()
+ \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec()
+ or pcre_dfa_exec()
+ \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec()
+ or pcre_dfa_exec()
+
+ The escapes that specify line endings are literal strings, exactly as
+ shown. 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
+ terminates the data input.
+
+ If \M is present, pcretest calls pcre_exec() several times, with dif-
+ ferent values in the match_limit and match_limit_recursion fields of
+ the pcre_extra data structure, until it finds the minimum numbers for
+ each parameter that allow pcre_exec() to complete. The match_limit num-
+ ber is a measure of the amount of backtracking that takes place, and
+ checking it out can be instructive. For most simple matches, the number
+ is quite small, but for patterns with very large numbers of matching
+ possibilities, it can become large very quickly with increasing length
+ of subject string. The match_limit_recursion number is a measure of how
+ much stack (or, if PCRE is compiled with NO_RECURSE, how much heap)
+ memory is needed to complete the match attempt.
When \O is used, the value specified may be higher or lower than the
size set by the -O command line option (or defaulted to 45); \O applies
only to the call of pcre_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
- and REG_NOTEOL to be passed to regexec() respectively.
+ per API to be used, the only option-setting sequences that have any
+ effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
+ to be passed to regexec().
+
+ 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.
- 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.
+ 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
Note that while patterns can be continued over several lines (a plain
">" prompt is used for continuations), data lines may not. However new-
- lines can be included in data by means of the \n escape.
+ lines can be included in data by means of the \n escape (or \r or \r\n
+ for those newline settings).
+
+
+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
+ If the pattern contains any callout requests, pcretest's callout func-
+ tion is called during matching. This works with both matching func-
+ tions. By default, the called function displays the callout number, the
+ start and current positions in the text at the callout time, and the
+ next pattern item to be tested. For example, the output
--->pqrabcdef
0 ^ ^ \d
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)
+ 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-
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: 29 June 2006
+Copyright (c) 1997-2006 University of Cambridge.
projects / exim.git / blobdiff