diff options
Diffstat (limited to 'doc/doc-txt')
| -rw-r--r-- | doc/doc-txt/ChangeLog | 6 | ||||
| -rw-r--r-- | doc/doc-txt/pcrepattern.txt | 363 | ||||
| -rw-r--r-- | doc/doc-txt/pcretest.txt | 369 |
3 files changed, 421 insertions, 317 deletions
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index bbdcb9843..5ff2e8869 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.155 2005/06/14 13:48:40 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.156 2005/06/15 08:57:10 ph10 Exp $ Change log file for Exim from version 4.21 ------------------------------------------- @@ -116,6 +116,10 @@ PH/12 Applied Alex Kiernan's patch for the API change for the error callback PH/13 Changed auto_thaw such that it does not apply to bounce messages. +PH/14 Imported PCRE 6.0; this was more than just a trivial operation because + the sources for PCRE have been re-arranged and more files are now + involved. + Exim version 4.51 ----------------- diff --git a/doc/doc-txt/pcrepattern.txt b/doc/doc-txt/pcrepattern.txt index 1dc800af4..29fbe5652 100644 --- a/doc/doc-txt/pcrepattern.txt +++ b/doc/doc-txt/pcrepattern.txt @@ -1,18 +1,17 @@ -This file contains the PCRE man page that describes the regular expressions -supported by PCRE version 5.0. Note that not all of the features are relevant +This file contains the PCRE man page that describes the regular expressions +supported by PCRE version 6.0. Note that not all of the features are relevant in the context of Exim. In particular, the version of PCRE that is compiled with Exim does not include UTF-8 support, there is no mechanism for changing the options with which the PCRE functions are called, and features such as callout are not accessible. ----------------------------------------------------------------------------- -PCRE(3) PCRE(3) - NAME PCRE - Perl-compatible regular expressions + PCRE REGULAR EXPRESSION DETAILS The syntax and semantics of the regular expressions supported by PCRE @@ -30,6 +29,14 @@ PCRE REGULAR EXPRESSION DETAILS of UTF-8 features in the section on UTF-8 support in the main pcre page. + The remainder of this document discusses the patterns that are sup- + ported by PCRE when its main matching function, pcre_exec(), is used. + From release 6.0, PCRE offers a second matching function, + pcre_dfa_exec(), which matches using a different algorithm that is not + Perl-compatible. The advantages and disadvantages of the alternative + function, and how it differs from the normal function, are discussed in + the pcrematching page. + A regular expression is a pattern that is matched against a subject string from left to right. Most characters stand for themselves in a pattern, and match the corresponding characters in the subject. As a @@ -37,15 +44,24 @@ PCRE REGULAR EXPRESSION DETAILS The quick brown fox - matches a portion of a subject string that is identical to itself. The - power of regular expressions comes from the ability to include alterna- - tives and repetitions in the pattern. These are encoded in the pattern - by the use of metacharacters, which do not stand for themselves but - instead are interpreted in some special way. - - There are two different sets of metacharacters: those that are recog- - nized anywhere in the pattern except within square brackets, and those - that are recognized in square brackets. Outside square brackets, the + matches a portion of a subject string that is identical to itself. When + caseless matching is specified (the PCRE_CASELESS option), letters are + matched independently of case. In UTF-8 mode, PCRE always understands + the concept of case for characters whose values are less than 128, so + caseless matching is always possible. For characters with higher val- + ues, the concept of case is supported if PCRE is compiled with Unicode + property support, but not otherwise. If you want to use caseless + matching for characters 128 and above, you must ensure that PCRE is + compiled with Unicode property support as well as with UTF-8 support. + + The power of regular expressions comes from the ability to include + alternatives and repetitions in the pattern. These are encoded in the + pattern by the use of metacharacters, which do not stand for themselves + but instead are interpreted in some special way. + + There are two different sets of metacharacters: those that are recog- + nized anywhere in the pattern except within square brackets, and those + that are recognized in square brackets. Outside square brackets, the metacharacters are as follows: \ general escape character with several uses @@ -64,7 +80,7 @@ PCRE REGULAR EXPRESSION DETAILS also "possessive quantifier" { start min/max quantifier - Part of a pattern that is in square brackets is called a "character + Part of a pattern that is in square brackets is called a "character class". In a character class the only metacharacters are: \ general escape character @@ -74,33 +90,33 @@ PCRE REGULAR EXPRESSION DETAILS syntax) ] terminates the character class - The following sections describe the use of each of the metacharacters. + The following sections describe the use of each of the metacharacters. BACKSLASH The backslash character has several uses. Firstly, if it is followed by - a non-alphanumeric character, it takes away any special meaning that - character may have. This use of backslash as an escape character + a non-alphanumeric character, it takes away any special meaning that + character may have. This use of backslash as an escape character applies both inside and outside character classes. - For example, if you want to match a * character, you write \* in the - pattern. This escaping action applies whether or not the following - character would otherwise be interpreted as a metacharacter, so it is - always safe to precede a non-alphanumeric with backslash to specify - that it stands for itself. In particular, if you want to match a back- + For example, if you want to match a * character, you write \* in the + pattern. This escaping action applies whether or not the following + character would otherwise be interpreted as a metacharacter, so it is + always safe to precede a non-alphanumeric with backslash to specify + that it stands for itself. In particular, if you want to match a back- slash, you write \\. - If a pattern is compiled with the PCRE_EXTENDED option, whitespace in - the pattern (other than in a character class) and characters between a + If a pattern is compiled with the PCRE_EXTENDED option, whitespace in + the pattern (other than in a character class) and characters between a # outside a character class and the next newline character are ignored. - An escaping backslash can be used to include a whitespace or # charac- + An escaping backslash can be used to include a whitespace or # charac- ter as part of the pattern. - If you want to remove the special meaning from a sequence of charac- - ters, you can do so by putting them between \Q and \E. This is differ- - ent from Perl in that $ and @ are handled as literals in \Q...\E - sequences in PCRE, whereas in Perl, $ and @ cause variable interpola- + If you want to remove the special meaning from a sequence of charac- + ters, you can do so by putting them between \Q and \E. This is differ- + ent from Perl in that $ and @ are handled as literals in \Q...\E + sequences in PCRE, whereas in Perl, $ and @ cause variable interpola- tion. Note the following examples: Pattern PCRE matches Perl matches @@ -110,16 +126,16 @@ BACKSLASH \Qabc\$xyz\E abc\$xyz abc\$xyz \Qabc\E\$\Qxyz\E abc$xyz abc$xyz - The \Q...\E sequence is recognized both inside and outside character + The \Q...\E sequence is recognized both inside and outside character classes. Non-printing characters A second use of backslash provides a way of encoding non-printing char- - acters in patterns in a visible manner. There is no restriction on the - appearance of non-printing characters, apart from the binary zero that - terminates a pattern, but when a pattern is being prepared by text - editing, it is usually easier to use one of the following escape + acters in patterns in a visible manner. There is no restriction on the + appearance of non-printing characters, apart from the binary zero that + terminates a pattern, but when a pattern is being prepared by text + editing, it is usually easier to use one of the following escape sequences than the binary character it represents: \a alarm, that is, the BEL character (hex 07) @@ -133,44 +149,44 @@ BACKSLASH \xhh character with hex code hh \x{hhh..} character with hex code hhh... (UTF-8 mode only) - The precise effect of \cx is as follows: if x is a lower case letter, - it is converted to upper case. Then bit 6 of the character (hex 40) is - inverted. Thus \cz becomes hex 1A, but \c{ becomes hex 3B, while \c; + The precise effect of \cx is as follows: if x is a lower case letter, + it is converted to upper case. Then bit 6 of the character (hex 40) is + inverted. Thus \cz becomes hex 1A, but \c{ becomes hex 3B, while \c; becomes hex 7B. - After \x, from zero to two hexadecimal digits are read (letters can be - in upper or lower case). In UTF-8 mode, any number of hexadecimal dig- - its may appear between \x{ and }, but the value of the character code - must be less than 2**31 (that is, the maximum hexadecimal value is - 7FFFFFFF). If characters other than hexadecimal digits appear between - \x{ and }, or if there is no terminating }, this form of escape is not - recognized. Instead, the initial \x will be interpreted as a basic hex- - adecimal escape, with no following digits, giving a character whose + After \x, from zero to two hexadecimal digits are read (letters can be + in upper or lower case). In UTF-8 mode, any number of hexadecimal dig- + its may appear between \x{ and }, but the value of the character code + must be less than 2**31 (that is, the maximum hexadecimal value is + 7FFFFFFF). If characters other than hexadecimal digits appear between + \x{ and }, or if there is no terminating }, this form of escape is not + recognized. Instead, the initial \x will be interpreted as a basic + hexadecimal escape, with no following digits, giving a character whose value is zero. Characters whose value is less than 256 can be defined by either of the - two syntaxes for \x when PCRE is in UTF-8 mode. There is no difference - in the way they are handled. For example, \xdc is exactly the same as + two syntaxes for \x when PCRE is in UTF-8 mode. There is no difference + in the way they are handled. For example, \xdc is exactly the same as \x{dc}. - After \0 up to two further octal digits are read. In both cases, if - there are fewer than two digits, just those that are present are used. - Thus the sequence \0\x\07 specifies two binary zeros followed by a BEL - character (code value 7). Make sure you supply two digits after the - initial zero if the pattern character that follows is itself an octal + After \0 up to two further octal digits are read. In both cases, if + there are fewer than two digits, just those that are present are used. + Thus the sequence \0\x\07 specifies two binary zeros followed by a BEL + character (code value 7). Make sure you supply two digits after the + initial zero if the pattern character that follows is itself an octal digit. The handling of a backslash followed by a digit other than 0 is compli- cated. Outside a character class, PCRE reads it and any following dig- - its as a decimal number. If the number is less than 10, or if there + its as a decimal number. If the number is less than 10, or if there have been at least that many previous capturing left parentheses in the - expression, the entire sequence is taken as a back reference. A - description of how this works is given later, following the discussion + expression, the entire sequence is taken as a back reference. A + description of how this works is given later, following the discussion of parenthesized subpatterns. - Inside a character class, or if the decimal number is greater than 9 - and there have not been that many capturing subpatterns, PCRE re-reads - up to three octal digits following the backslash, and generates a sin- + Inside a character class, or if the decimal number is greater than 9 + and there have not been that many capturing subpatterns, PCRE re-reads + up to three octal digits following the backslash, and generates a sin- gle byte from the least significant 8 bits of the value. Any subsequent digits stand for themselves. For example: @@ -189,19 +205,19 @@ BACKSLASH \81 is either a back reference, or a binary zero followed by the two characters "8" and "1" - Note that octal values of 100 or greater must not be introduced by a + Note that octal values of 100 or greater must not be introduced by a leading zero, because no more than three octal digits are ever read. - All the sequences that define a single byte value or a single UTF-8 + All the sequences that define a single byte value or a single UTF-8 character (in UTF-8 mode) can be used both inside and outside character - classes. In addition, inside a character class, the sequence \b is + classes. In addition, inside a character class, the sequence \b is interpreted as the backspace character (hex 08), and the sequence \X is - interpreted as the character "X". Outside a character class, these + interpreted as the character "X". Outside a character class, these sequences have different meanings (see below). Generic character types - The third use of backslash is for specifying generic character types. + The third use of backslash is for specifying generic character types. The following are always recognized: \d any decimal digit @@ -212,48 +228,48 @@ BACKSLASH \W any "non-word" character Each pair of escape sequences partitions the complete set of characters - into two disjoint sets. Any given character matches one, and only one, + into two disjoint sets. Any given character matches one, and only one, of each pair. These character type sequences can appear both inside and outside char- - acter classes. They each match one character of the appropriate type. - If the current matching point is at the end of the subject string, all + acter classes. They each match one character of the appropriate type. + If the current matching point is at the end of the subject string, all of them fail, since there is no character to match. - For compatibility with Perl, \s does not match the VT character (code - 11). This makes it different from the the POSIX "space" class. The \s + For compatibility with Perl, \s does not match the VT character (code + 11). This makes it different from the the POSIX "space" class. The \s characters are HT (9), LF (10), FF (12), CR (13), and space (32). A "word" character is an underscore or any character less than 256 that - is a letter or digit. The definition of letters and digits is con- - trolled by PCRE's low-valued character tables, and may vary if locale- - specific matching is taking place (see "Locale support" in the pcreapi - page). For example, in the "fr_FR" (French) locale, some character - codes greater than 128 are used for accented letters, and these are + is a letter or digit. The definition of letters and digits is con- + trolled by PCRE's low-valued character tables, and may vary if locale- + specific matching is taking place (see "Locale support" in the pcreapi + page). For example, in the "fr_FR" (French) locale, some character + codes greater than 128 are used for accented letters, and these are matched by \w. - In UTF-8 mode, characters with values greater than 128 never match \d, + In UTF-8 mode, characters with values greater than 128 never match \d, \s, or \w, and always match \D, \S, and \W. This is true even when Uni- code character property support is available. Unicode character properties When PCRE is built with Unicode character property support, three addi- - tional escape sequences to match generic character types are available + tional escape sequences to match generic character types are available when UTF-8 mode is selected. They are: \p{xx} a character with the xx property \P{xx} a character without the xx property \X an extended Unicode sequence - The property names represented by xx above are limited to the Unicode - general category properties. Each character has exactly one such prop- - erty, specified by a two-letter abbreviation. For compatibility with - Perl, negation can be specified by including a circumflex between the - opening brace and the property name. For example, \p{^Lu} is the same + The property names represented by xx above are limited to the Unicode + general category properties. Each character has exactly one such prop- + erty, specified by a two-letter abbreviation. For compatibility with + Perl, negation can be specified by including a circumflex between the + opening brace and the property name. For example, \p{^Lu} is the same as \P{Lu}. - If only one letter is specified with \p or \P, it includes all the + If only one letter is specified with \p or \P, it includes all the properties that start with that letter. In this case, in the absence of negation, the curly brackets in the escape sequence are optional; these two examples have the same effect: @@ -307,33 +323,33 @@ BACKSLASH Zp Paragraph separator Zs Space separator - Extended properties such as "Greek" or "InMusicalSymbols" are not sup- + Extended properties such as "Greek" or "InMusicalSymbols" are not sup- ported by PCRE. - Specifying caseless matching does not affect these escape sequences. + Specifying caseless matching does not affect these escape sequences. For example, \p{Lu} always matches only upper case letters. - The \X escape matches any number of Unicode characters that form an + The \X escape matches any number of Unicode characters that form an extended Unicode sequence. \X is equivalent to (?>\PM\pM*) - That is, it matches a character without the "mark" property, followed - by zero or more characters with the "mark" property, and treats the - sequence as an atomic group (see below). Characters with the "mark" + That is, it matches a character without the "mark" property, followed + by zero or more characters with the "mark" property, and treats the + sequence as an atomic group (see below). Characters with the "mark" property are typically accents that affect the preceding character. - Matching characters by Unicode property is not fast, because PCRE has - to search a structure that contains data for over fifteen thousand + Matching characters by Unicode property is not fast, because PCRE has + to search a structure that contains data for over fifteen thousand characters. That is why the traditional escape sequences such as \d and \w do not use Unicode properties in PCRE. Simple assertions The fourth use of backslash is for certain simple assertions. An asser- - tion specifies a condition that has to be met at a particular point in - a match, without consuming any characters from the subject string. The - use of subpatterns for more complicated assertions is described below. + tion specifies a condition that has to be met at a particular point in + a match, without consuming any characters from the subject string. The + use of subpatterns for more complicated assertions is described below. The backslashed assertions are: \b matches at a word boundary @@ -343,42 +359,42 @@ BACKSLASH \z matches at end of subject \G matches at first matching position in subject - These assertions may not appear in character classes (but note that \b + These assertions may not appear in character classes (but note that \b has a different meaning, namely the backspace character, inside a char- acter class). - A word boundary is a position in the subject string where the current - character and the previous character do not both match \w or \W (i.e. - one matches \w and the other matches \W), or the start or end of the + A word boundary is a position in the subject string where the current + character and the previous character do not both match \w or \W (i.e. + one matches \w and the other matches \W), or the start or end of the string if the first or last character matches \w, respectively. - The \A, \Z, and \z assertions differ from the traditional circumflex + The \A, \Z, and \z assertions differ from the traditional circumflex and dollar (described in the next section) in that they only ever match - at the very start and end of the subject string, whatever options are - set. Thus, they are independent of multiline mode. These three asser- + at the very start and end of the subject string, whatever options are + set. Thus, they are independent of multiline mode. These three asser- tions are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options, which - affect only the behaviour of the circumflex and dollar metacharacters. - However, if the startoffset argument of pcre_exec() is non-zero, indi- + affect only the behaviour of the circumflex and dollar metacharacters. + However, if the startoffset argument of pcre_exec() is non-zero, indi- cating that matching is to start at a point other than the beginning of - the subject, \A can never match. The difference between \Z and \z is - that \Z matches before a newline that is the last character of the - string as well as at the end of the string, whereas \z matches only at + the subject, \A can never match. The difference between \Z and \z is + that \Z matches before a newline that is the last character of the + string as well as at the end of the string, whereas \z matches only at the end. - The \G assertion is true only when the current matching position is at - the start point of the match, as specified by the startoffset argument - of pcre_exec(). It differs from \A when the value of startoffset is - non-zero. By calling pcre_exec() multiple times with appropriate argu- + The \G assertion is true only when the current matching position is at + the start point of the match, as specified by the startoffset argument + of pcre_exec(). It differs from \A when the value of startoffset is + non-zero. By calling pcre_exec() multiple times with appropriate argu- ments, you can mimic Perl's /g option, and it is in this kind of imple- mentation where \G can be useful. - Note, however, that PCRE's interpretation of \G, as the start of the + Note, however, that PCRE's interpretation of \G, as the start of the current match, is subtly different from Perl's, which defines it as the - end of the previous match. In Perl, these can be different when the - previously matched string was empty. Because PCRE does just one match + end of the previous match. In Perl, these can be different when the + previously matched string was empty. Because PCRE does just one match at a time, it cannot reproduce this behaviour. - If all the alternatives of a pattern begin with \G, the expression is + If all the alternatives of a pattern begin with \G, the expression is anchored to the starting match position, and the "anchored" flag is set in the compiled regular expression. @@ -386,73 +402,73 @@ BACKSLASH CIRCUMFLEX AND DOLLAR Outside a character class, in the default matching mode, the circumflex - character is an assertion that is true only if the current matching - point is at the start of the subject string. If the startoffset argu- - ment of pcre_exec() is non-zero, circumflex can never match if the - PCRE_MULTILINE option is unset. Inside a character class, circumflex + character is an assertion that is true only if the current matching + point is at the start of the subject string. If the startoffset argu- + ment of pcre_exec() is non-zero, circumflex can never match if the + PCRE_MULTILINE option is unset. Inside a character class, circumflex has an entirely different meaning (see below). - Circumflex need not be the first character of the pattern if a number - of alternatives are involved, but it should be the first thing in each - alternative in which it appears if the pattern is ever to match that - branch. If all possible alternatives start with a circumflex, that is, - if the pattern is constrained to match only at the start of the sub- - ject, it is said to be an "anchored" pattern. (There are also other + Circumflex need not be the first character of the pattern if a number + of alternatives are involved, but it should be the first thing in each + alternative in which it appears if the pattern is ever to match that + branch. If all possible alternatives start with a circumflex, that is, + if the pattern is constrained to match only at the start of the sub- + ject, it is said to be an "anchored" pattern. (There are also other constructs that can cause a pattern to be anchored.) - A dollar character is an assertion that is true only if the current - matching point is at the end of the subject string, or immediately + A dollar character is an assertion that is true only if the current + matching point is at the end of the subject string, or immediately before a newline character that is the last character in the string (by - default). Dollar need not be the last character of the pattern if a - number of alternatives are involved, but it should be the last item in - any branch in which it appears. Dollar has no special meaning in a + default). Dollar need not be the last character of the pattern if a + number of alternatives are involved, but it should be the last item in + any branch in which it appears. Dollar has no special meaning in a character class. - The meaning of dollar can be changed so that it matches only at the - very end of the string, by setting the PCRE_DOLLAR_ENDONLY option at + The meaning of dollar can be changed so that it matches only at the + very end of the string, by setting the PCRE_DOLLAR_ENDONLY option at compile time. This does not affect the \Z assertion. The meanings of the circumflex and dollar characters are changed if the PCRE_MULTILINE option is set. When this is the case, they match immedi- - ately after and immediately before an internal newline character, - respectively, in addition to matching at the start and end of the sub- - ject string. For example, the pattern /^abc$/ matches the subject - string "def\nabc" (where \n represents a newline character) in multi- + ately after and immediately before an internal newline character, + respectively, in addition to matching at the start and end of the sub- + ject string. For example, the pattern /^abc$/ matches the subject + string "def\nabc" (where \n represents a newline character) in multi- line mode, but not otherwise. Consequently, patterns that are anchored - in single line mode because all branches start with ^ are not anchored - in multiline mode, and a match for circumflex is possible when the - startoffset argument of pcre_exec() is non-zero. The PCRE_DOL- + in single line mode because all branches start with ^ are not anchored + in multiline mode, and a match for circumflex is possible when the + startoffset argument of pcre_exec() is non-zero. The PCRE_DOL- LAR_ENDONLY option is ignored if PCRE_MULTILINE is set. - Note that the sequences \A, \Z, and \z can be used to match the start - and end of the subject in both modes, and if all branches of a pattern - start with \A it is always anchored, whether PCRE_MULTILINE is set or + Note that the sequences \A, \Z, and \z can be used to match the start + and end of the subject in both modes, and if all branches of a pattern + start with \A it is always anchored, whether PCRE_MULTILINE is set or not. FULL STOP (PERIOD, DOT) Outside a character class, a dot in the pattern matches any one charac- - ter in the subject, including a non-printing character, but not (by - default) newline. In UTF-8 mode, a dot matches any UTF-8 character, + ter in the subject, including a non-printing character, but not (by + default) newline. In UTF-8 mode, a dot matches any UTF-8 character, which might be more than one byte long, except (by default) newline. If - the PCRE_DOTALL option is set, dots match newlines as well. The han- - dling of dot is entirely independent of the handling of circumflex and - dollar, the only relationship being that they both involve newline + the PCRE_DOTALL option is set, dots match newlines as well. The han- + dling of dot is entirely independent of the handling of circumflex and + dollar, the only relationship being that they both involve newline characters. Dot has no special meaning in a character class. MATCHING A SINGLE BYTE Outside a character class, the escape sequence \C matches any one byte, - both in and out of UTF-8 mode. Unlike a dot, it can match a newline. - The feature is provided in Perl in order to match individual bytes in - UTF-8 mode. Because it breaks up UTF-8 characters into individual - bytes, what remains in the string may be a malformed UTF-8 string. For + both in and out of UTF-8 mode. Unlike a dot, it can match a newline. + The feature is provided in Perl in order to match individual bytes in + UTF-8 mode. Because it breaks up UTF-8 characters into individual + bytes, what remains in the string may be a malformed UTF-8 string. For this reason, the \C escape sequence is best avoided. - PCRE does not allow \C to appear in lookbehind assertions (described - below), because in UTF-8 mode this would make it impossible to calcu- + PCRE does not allow \C to appear in lookbehind assertions (described + below), because in UTF-8 mode this would make it impossible to calcu- late the length of the lookbehind. @@ -461,35 +477,40 @@ SQUARE BRACKETS AND CHARACTER CLASSES An opening square bracket introduces a character class, terminated by a closing square bracket. A closing square bracket on its own is not spe- cial. If a closing square bracket is required as a member of the class, - it should be the first data character in the class (after an initial + it should be the first data character in the class (after an initial circumflex, if present) or escaped with a backslash. - A character class matches a single character in the subject. In UTF-8 - mode, the character may occupy more than one byte. A matched character + A character class matches a single character in the subject. In UTF-8 + mode, the character may occupy more than one byte. A matched character must be in the set of characters defined by the class, unless the first - character in the class definition is a circumflex, in which case the - subject character must not be in the set defined by the class. If a - circumflex is actually required as a member of the class, ensure it is + character in the class definition is a circumflex, in which case the + subject character must not be in the set defined by the class. If a + circumflex is actually required as a member of the class, ensure it is not the first character, or escape it with a backslash. - For example, the character class [aeiou] matches any lower case vowel, - while [^aeiou] matches any character that is not a lower case vowel. + For example, the character class [aeiou] matches any lower case vowel, + while [^aeiou] matches any character that is not a lower case vowel. Note that a circumflex is just a convenient notation for specifying the - characters that are in the class by enumerating those that are not. A - class that starts with a circumflex is not an assertion: it still con- - sumes a character from the subject string, and therefore it fails if + characters that are in the class by enumerating those that are not. A + class that starts with a circumflex is not an assertion: it still con- + sumes a character from the subject string, and therefore it fails if the current pointer is at the end of the string. - In UTF-8 mode, characters with values greater than 255 can be included - in a class as a literal string of bytes, or by using the \x{ escaping + In UTF-8 mode, characters with values greater than 255 can be included + in a class as a literal string of bytes, or by using the \x{ escaping mechanism. - When caseless matching is set, any letters in a class represent both - their upper case and lower case versions, so for example, a caseless - [aeiou] matches "A" as well as "a", and a caseless [^aeiou] does not - match "A", whereas a caseful version would. When running in UTF-8 mode, - PCRE supports the concept of case for characters with values greater - than 128 only when it is compiled with Unicode property support. + When caseless matching is set, any letters in a class represent both + their upper case and lower case versions, so for example, a caseless + [aeiou] matches "A" as well as "a", and a caseless [^aeiou] does not + match "A", whereas a caseful version would. In UTF-8 mode, PCRE always + understands the concept of case for characters whose values are less + than 128, so caseless matching is always possible. For characters with + higher values, the concept of case is supported if PCRE is compiled + with Unicode property support, but not otherwise. If you want to use + caseless matching for characters 128 and above, you must ensure that + PCRE is compiled with Unicode property support as well as with UTF-8 + support. The newline character is never treated in any special way in character classes, whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE @@ -1409,5 +1430,5 @@ CALLOUTS gether. A complete description of the interface to the callout function is given in the pcrecallout documentation. -Last updated: 09 September 2004 -Copyright (c) 1997-2004 University of Cambridge. +Last updated: 28 February 2005 +Copyright (c) 1997-2005 University of Cambridge. diff --git a/doc/doc-txt/pcretest.txt b/doc/doc-txt/pcretest.txt index 9e9b70ef4..384a6c38f 100644 --- a/doc/doc-txt/pcretest.txt +++ b/doc/doc-txt/pcretest.txt @@ -1,5 +1,5 @@ -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. ------------------------------------------------------------------------------- @@ -12,7 +12,7 @@ NAME 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 @@ -29,95 +29,100 @@ OPTIONS 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 @@ -128,95 +133,96 @@ PATTERN MODIFIERS /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) @@ -247,6 +253,8 @@ DATA LINES 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 @@ -259,6 +267,8 @@ DATA LINES \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 @@ -266,35 +276,53 @@ DATA LINES \>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 @@ -350,25 +378,76 @@ OUTPUT FROM PCRETEST 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 @@ -380,76 +459,76 @@ CALLOUTS +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. |