diff -r 000000000000 -r 7f656887cf89 libraries/spcre/libpcre/pcre/doc/pcretest.txt --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libraries/spcre/libpcre/pcre/doc/pcretest.txt Wed Jun 23 15:52:26 2010 +0100 @@ -0,0 +1,654 @@ +PCRETEST(1) PCRETEST(1) + + +NAME + pcretest - a program for testing Perl-compatible regular expressions. + + +SYNOPSIS + + 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 + expressions. This document describes the features of the test program; + for details of the regular expressions themselves, see the pcrepattern + documentation. For details of the PCRE library function calls and their + options, see the pcreapi documentation. + + +OPTIONS + + -b Behave as if each regex has the /B (show bytecode) modifier; + the internal form is output after compilation. + + -C Output the version number of the PCRE library, and all avail- + able information about the optional features that are + included, and then exit. + + -d Behave as if each regex has the /D (debug) modifier; the + internal form and information about the compiled pattern is + output after compilation; -d is equivalent to -b -i. + + -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). + + -help Output a brief summary these options and then exit. + + -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 + 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() or pcre_dfa_exec() to be osize. The + default value is 45, which is enough for 14 capturing subex- + pressions for pcre_exec() or 22 different matches for + pcre_dfa_exec(). The vector size can be changed for individ- + ual matching calls by including \O in the data line (see + below). + + -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. + + -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. You can control the number of iterations that are + used for timing by following -t with a number (as a separate + item on the command line). For example, "-t 1000" would iter- + ate 1000 times. The default is to iterate 500000 times. + + -tm This is like -t except that it times only the matching phase, + not the compile or study phases. + + +DESCRIPTION + + 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 + "re>" to prompt for regular expressions, and "data>" to prompt for data + lines. + + When pcretest is built, a configuration option can specify that it + should be linked with the libreadline library. When this is done, if + the input is from a terminal, it is read using the readline() function. + This provides line-editing and history facilities. The output from the + -help option states whether or not readline() will be used. + + 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- + ber of data lines to be matched against the pattern. + + 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, etc., depending on the newline setting) in a single line of input + to encode the newline sequences. 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: + + /(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 + 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- + 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 + 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. + + +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 + 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 + they do in Perl. For example: + + /caseless/i + + 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 + /f PCRE_FIRSTLINE + /J PCRE_DUPNAMES + /N PCRE_NO_AUTO_CAPTURE + /U PCRE_UNGREEDY + /X PCRE_EXTRA + / PCRE_JAVASCRIPT_COMPAT + / PCRE_NEWLINE_CR + / PCRE_NEWLINE_LF + / PCRE_NEWLINE_CRLF + / PCRE_NEWLINE_ANYCRLF + / PCRE_NEWLINE_ANY + / PCRE_BSR_ANYCRLF + / PCRE_BSR_UNICODE + + Those specifying line ending sequences are literal strings as shown, + but the letters can be in either case. This example sets multiline + matching with CRLF as the line ending sequence: + + /^abc/m + + Details of the meanings of these PCRE options are given in the pcreapi + documentation. + + 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 + 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 + 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- + 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 + 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 /B modifier is a debugging feature. It requests that pcretest out- + put a representation of the compiled byte code after compilation. Nor- + mally this information contains length and offset values; however, if + /Z is also present, this data is replaced by spaces. This is a special + feature for use in the automatic test scripts; it ensures that the same + output is generated for different internal link sizes. + + 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 + 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- + put. + + The /D modifier is a PCRE debugging feature, and is equivalent to /BI, + that is, both the /B and the /I modifiers. + + 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 + 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 + section about saving and reloading compiled patterns below. + + 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- + 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 /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 + 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 + following escapes are recognized: + + \a alarm (BEL, \x07) + \b backspace (\x08) + \e escape (\x27) + \f formfeed (\x0c) + \n newline (\x0a) + \qdd set the PCRE_MATCH_LIMIT limit to dd + (any number of digits) + \r carriage return (\x0d) + \t tab (\x09) + \v vertical tab (\x0b) + \nnn octal character (up to 3 octal digits) + \xhh hexadecimal character (up to 2 hex digits) + \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 + "name" after a successful match (name termin- + ated by next non alphanumeric character) + \C+ show the current captured substrings at callout + time + \C- do not supply a callout function + \C!n return 1 instead of 0 when callout number n is + reached + \C!n!m return 1 instead of 0 when callout number n is + 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 + "name" after a successful match (name termin- + ated by next non-alphanumeric character) + \L call pcre_get_substringlist() after a + successful match + \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() or pcre_dfa_exec() + \>dd start the match at offset dd (any number of digits); + this sets the startoffset argument for pcre_exec() + or pcre_dfa_exec() + \ pass the PCRE_NEWLINE_CR option to pcre_exec() + or pcre_dfa_exec() + \ pass the PCRE_NEWLINE_LF option to pcre_exec() + or pcre_dfa_exec() + \ pass the PCRE_NEWLINE_CRLF option to pcre_exec() + or pcre_dfa_exec() + \ pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec() + or pcre_dfa_exec() + \ pass the PCRE_NEWLINE_ANY option to pcre_exec() + or pcre_dfa_exec() + + The escapes that specify line ending sequences are literal strings, + exactly as shown. No more than one newline setting should be present in + any data line. + + 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 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, 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 original + UTF-8 rules of RFC 2279. This allows for values in the range 0 to + 0x7FFFFFFF. Note that not all of those are valid Unicode code points, + or indeed valid UTF-8 characters according to the later rules in RFC + 3629. + + +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. + + +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 + matched the whole pattern. Otherwise, it outputs "No match" or "Partial + match" when pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR- + TIAL, respectively, and otherwise the PCRE negative error number. Here + is an example of an interactive pcretest run. + + $ pcretest + PCRE version 7.0 30-Nov-2006 + + re> /^abc(\d+)/ + data> abc123 + 0: abc123 + 1: 123 + data> xyz + No match + + Note that unset capturing substrings that are not followed by one that + is set are not returned by pcre_exec(), and are not shown by pcretest. + In the following example, there are two capturing substrings, but when + the first data line is matched, the second, unset substring is not + shown. An "internal" unset substring is shown as "", as for the + second data line. + + re> /(a)|(b)/ + data> a + 0: a + 1: a + data> b + 0: b + 1: + 2: b + + If the strings contain any non-printing characters, they are output as + \0x escapes, or as \x{...} escapes if the /8 modifier was present on + the pattern. See below for the definition of non-printing characters. + If the pattern has the /+ modifier, the output for substring 0 is fol- + lowed 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 /g or /G 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 \C, \G, or \L 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 paren- + theses after each string for \C and \G. + + Note that whereas 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 (or \r, \r\n, + etc., depending on the newline sequence setting). + + +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 /g 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> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ + 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. 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 + 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 + output. For example: + + re> /\d?[A-E]\*/C + data> E* + --->E* + +0 ^ \d? + +3 ^ [A-E] + +8 ^^ \* + +10 ^ ^ + 0: E* + + 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 + the pcrecallout documentation. + + +NON-PRINTING CHARACTERS + + When pcretest is outputting text in the compiled version of a pattern, + bytes other than 32-126 are always treated as non-printing characters + are are therefore shown as hex escapes. + + When pcretest is outputting text that is a matched part of a subject + string, it behaves in the same way, unless a different locale has been + set for the pattern (using the /L modifier). In this case, the + isprint() function to distinguish printing and non-printing characters. + + +SAVING AND RELOADING COMPILED PATTERNS + + 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 + file name. For example: + + /pattern/im >/some/file + + 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 + 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 + compiled pattern. If there is additional study data, this follows imme- + 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 + delimited by < characters. For example: + + re>