| .TH PCRETEST 1 |
| .SH NAME |
| pcretest - a program for testing Perl-compatible regular expressions. |
| .SH SYNOPSIS |
| .B pcretest "[-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]" |
| |
| \fBpcretest\fR was written as a test program for the PCRE regular expression |
| library itself, but it can also be used for experimenting with regular |
| expressions. This man page describes the features of the test program; for |
| details of the regular expressions themselves, see the \fBpcre\fR man page. |
| |
| .SH OPTIONS |
| .TP 10 |
| \fB-d\fR |
| Behave as if each regex had the \fB/D\fR modifier (see below); the internal |
| form is output after compilation. |
| .TP 10 |
| \fB-i\fR |
| Behave as if each regex had the \fB/I\fR modifier; information about the |
| compiled pattern is given after compilation. |
| .TP 10 |
| \fB-m\fR |
| 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, \fB-s\fR is a synonym for \fB-m\fR. |
| .TP 10 |
| \fB-o\fR \fIosize\fR |
| Set the number of elements in the output vector that is used when calling PCRE |
| to be \fIosize\fR. The default value is 45, which is enough for 14 capturing |
| subexpressions. The vector size can be changed for individual matching calls by |
| including \\O in the data line (see below). |
| .TP 10 |
| \fB-p\fR |
| Behave as if each regex has \fB/P\fR modifier; the POSIX wrapper API is used |
| to call PCRE. None of the other options has any effect when \fB-p\fR is set. |
| .TP 10 |
| \fB-t\fR |
| Run each compile, study, and match 20000 times with a timer, and output |
| resulting time per compile or match (in milliseconds). Do not set \fB-t\fR with |
| \fB-m\fR, because you will then get the size output 20000 times and the timing |
| will be distorted. |
| |
| |
| .SH DESCRIPTION |
| |
| If \fBpcretest\fR 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 "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 number of data |
| lines to be matched against the pattern. 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-alphameric delimiters other than |
| backslash, for example |
| |
| /(a|bc)x+yz/ |
| |
| White space before the initial delimiter is ignored. A regular expression may |
| be continued over several input lines, in which case the newline 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-alphameric, this does not affect its interpretation. |
| If the terminating delimiter is immediately followed 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 finishes with a |
| backslash, because |
| |
| /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. |
| |
| |
| .SH PATTERN MODIFIERS |
| |
| The pattern may be followed by \fBi\fR, \fBm\fR, \fBs\fR, or \fBx\fR to set the |
| PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, |
| respectively. For example: |
| |
| /caseless/i |
| |
| These modifier letters have the same effect as they do in Perl. There are |
| others which set PCRE options that do not correspond to anything in Perl: |
| \fB/A\fR, \fB/E\fR, and \fB/X\fR set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and |
| PCRE_EXTRA respectively. |
| |
| Searching for all possible matches within each subject string can be requested |
| by the \fB/g\fR or \fB/G\fR modifier. After finding a match, PCRE is called |
| again to search the remainder of the subject string. The difference between |
| \fB/g\fR and \fB/G\fR is that the former uses the \fIstartoffset\fR argument to |
| \fBpcre_exec()\fR 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 \fBpcre_exec()\fR in a \fB/g\fR or \fB/G\fR 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 handles such cases when using the |
| \fB/g\fR modifier or the \fBsplit()\fR function. |
| |
| There are a number of other modifiers for controlling the way \fBpcretest\fR |
| operates. |
| |
| The \fB/+\fR 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 \fB/L\fR modifier must be followed directly by the name of a locale, for |
| example, |
| |
| /pattern/Lfr |
| |
| For this reason, it must be the last modifier letter. The given locale is set, |
| \fBpcre_maketables()\fR is called to build a set of character tables for the |
| locale, and this is then passed to \fBpcre_compile()\fR when compiling the |
| regular expression. Without an \fB/L\fR modifier, NULL is passed as the tables |
| pointer; that is, \fB/L\fR applies only to the expression on which it appears. |
| |
| The \fB/I\fR modifier requests that \fBpcretest\fR output information about the |
| compiled expression (whether it is anchored, has a fixed first character, and |
| so on). It does this by calling \fBpcre_fullinfo()\fR after compiling an |
| expression, and outputting the information it gets back. If the pattern is |
| studied, the results of that are also output. |
| |
| The \fB/D\fR modifier is a PCRE debugging feature, which also assumes \fB/I\fR. |
| It causes the internal form of compiled regular expressions to be output after |
| compilation. |
| |
| The \fB/S\fR modifier causes \fBpcre_study()\fR to be called after the |
| expression has been compiled, and the results used when the expression is |
| matched. |
| |
| The \fB/M\fR modifier causes the size of memory block used to hold the compiled |
| pattern to be output. |
| |
| The \fB/P\fR modifier causes \fBpcretest\fR to call PCRE via the POSIX wrapper |
| API rather than its native API. When this is done, all other modifiers except |
| \fB/i\fR, \fB/m\fR, and \fB/+\fR are ignored. REG_ICASE is set if \fB/i\fR is |
| present, and REG_NEWLINE is set if \fB/m\fR is present. The wrapper functions |
| force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. |
| |
| The \fB/8\fR modifier causes \fBpcretest\fR to call PCRE with the PCRE_UTF8 |
| option set. This turns on the (currently incomplete) support for UTF-8 |
| character handling in PCRE, provided 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. |
| |
| |
| .SH DATA LINES |
| |
| Before each data line is passed to \fBpcre_exec()\fR, leading and trailing |
| whitespace is removed, and it is then scanned for \\ escapes. The following are |
| recognized: |
| |
| \\a alarm (= BEL) |
| \\b backspace |
| \\e escape |
| \\f formfeed |
| \\n newline |
| \\r carriage return |
| \\t tab |
| \\v vertical tab |
| \\nnn octal character (up to 3 octal digits) |
| \\xhh hexadecimal character (up to 2 hex digits) |
| \\x{hh...} hexadecimal UTF-8 character |
| |
| \\A pass the PCRE_ANCHORED option to \fBpcre_exec()\fR |
| \\B pass the PCRE_NOTBOL option to \fBpcre_exec()\fR |
| \\Cdd call pcre_copy_substring() for substring dd |
| after a successful match (any decimal number |
| less than 32) |
| \\Gdd call pcre_get_substring() for substring dd |
| after a successful match (any decimal number |
| less than 32) |
| \\L call pcre_get_substringlist() after a |
| successful match |
| \\N pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fR |
| \\Odd set the size of the output vector passed to |
| \fBpcre_exec()\fR to dd (any number of decimal |
| digits) |
| \\Z pass the PCRE_NOTEOL option to \fBpcre_exec()\fR |
| |
| When \\O is used, it may be higher or lower than the size set by the \fB-O\fR |
| option (or defaulted to 45); \\O applies only to the call of \fBpcre_exec()\fR |
| for the line in which it appears. |
| |
| 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 \fB/P\fR was present on the regex, causing the POSIX wrapper API to be used, |
| only \fB\B\fR, and \fB\Z\fR have any effect, causing REG_NOTBOL and REG_NOTEOL |
| to be passed to \fBregexec()\fR respectively. |
| |
| The use of \\x{hh...} to represent UTF-8 characters is not dependent on the use |
| of the \fB/8\fR 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. |
| |
| |
| .SH OUTPUT FROM PCRETEST |
| |
| When a match succeeds, pcretest outputs the list of captured substrings that |
| \fBpcre_exec()\fR returns, starting with number 0 for the string that matched |
| the whole pattern. Here is an example of an interactive pcretest run. |
| |
| $ pcretest |
| PCRE version 2.06 08-Jun-1999 |
| |
| re> /^abc(\\d+)/ |
| data> abc123 |
| 0: abc123 |
| 1: 123 |
| data> xyz |
| No match |
| |
| If the strings contain any non-printing characters, they are output as \\0x |
| escapes, or as \\x{...} escapes if the \fB/8\fR modifier was present on the |
| pattern. If the pattern has the \fB/+\fR modifier, then the output for |
| substring 0 is followed by the the rest of the subject string, identified by |
| "0+" like this: |
| |
| re> /cat/+ |
| data> cataract |
| 0: cat |
| 0+ aract |
| |
| If the pattern has the \fB/g\fR or \fB/G\fR modifier, the results of successive |
| matching attempts are output in sequence, like this: |
| |
| re> /\\Bi(\\w\\w)/g |
| data> Mississippi |
| 0: iss |
| 1: ss |
| 0: iss |
| 1: ss |
| 0: ipp |
| 1: pp |
| |
| "No match" is output only if the first match attempt fails. |
| |
| If any of the sequences \fB\\C\fR, \fB\\G\fR, or \fB\\L\fR are present in a |
| data line that 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 string for \fB\\C\fR and \fB\\G\fR. |
| |
| Note that while patterns can be continued over several lines (a plain ">" |
| prompt is used for continuations), data lines may not. However newlines can be |
| included in data by means of the \\n escape. |
| |
| |
| .SH AUTHOR |
| Philip Hazel <ph10@cam.ac.uk> |
| .br |
| University Computing Service, |
| .br |
| New Museums Site, |
| .br |
| Cambridge CB2 3QG, England. |
| .br |
| Phone: +44 1223 334714 |
| |
| Last updated: 15 August 2001 |
| .br |
| Copyright (c) 1997-2001 University of Cambridge. |