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Diffstat (limited to 'doc/pcre2api.3')
| -rw-r--r-- | doc/pcre2api.3 | 56 |
1 files changed, 35 insertions, 21 deletions
diff --git a/doc/pcre2api.3 b/doc/pcre2api.3 index b0a52ca..6cc2bbd 100644 --- a/doc/pcre2api.3 +++ b/doc/pcre2api.3 @@ -1,4 +1,4 @@ -.TH PCRE2API 3 "16 February 2020" "PCRE2 10.35" +.TH PCRE2API 3 "24 February 2020" "PCRE2 10.35" .SH NAME PCRE2 - Perl-compatible regular expressions (revised API) .sp @@ -1420,13 +1420,13 @@ documentation. .sp If this bit is set, letters in the pattern match both upper and lower case letters in the subject. It is equivalent to Perl's /i option, and it can be -changed within a pattern by a (?i) option setting. If PCRE2_UTF is set, Unicode -properties are used for all characters with more than one other case, and for -all characters whose code points are greater than U+007F. For lower valued -characters with only one other case, a lookup table is used for speed. When -PCRE2_UTF is not set, a lookup table is used for all code points less than 256, -and higher code points (available only in 16-bit or 32-bit mode) are treated as -not having another case. +changed within a pattern by a (?i) option setting. If either PCRE2_UTF or +PCRE2_UCP is set, Unicode properties are used for all characters with more than +one other case, and for all characters whose code points are greater than +U+007F. For lower valued characters with only one other case, a lookup table is +used for speed. When neither PCRE2_UTF nor PCRE2_UCP is set, a lookup table is +used for all code points less than 256, and higher code points (available only +in 16-bit or 32-bit mode) are treated as not having another case. .sp PCRE2_DOLLAR_ENDONLY .sp @@ -1769,10 +1769,11 @@ are not representable in UTF-16. .sp PCRE2_UCP .sp -This option changes the way PCRE2 processes \eB, \eb, \eD, \ed, \eS, \es, \eW, -\ew, and some of the POSIX character classes. By default, only ASCII characters -are recognized, but if PCRE2_UCP is set, Unicode properties are used instead to -classify characters. More details are given in the section on +This option has two effects. Firstly, it change the way PCRE2 processes \eB, +\eb, \eD, \ed, \eS, \es, \eW, \ew, and some of the POSIX character classes. By +default, only ASCII characters are recognized, but if PCRE2_UCP is set, Unicode +properties are used instead to classify characters. More details are given in +the section on .\" HTML <a href="pcre2pattern.html#genericchartypes"> .\" </a> generic character types @@ -1782,8 +1783,13 @@ in the \fBpcre2pattern\fP .\" page. If you set PCRE2_UCP, matching one of the items it affects takes much -longer. The option is available only if PCRE2 has been compiled with Unicode -support (which is the default). +longer. +.P +The second effect of PCRE2_UCP is to force the use of Unicode properties for +upper/lower casing operations on characters with code points greater than 127, +even when PCRE2_UTF is not set. This makes it possible, for example, to process +strings in the 16-bit UCS-2 code. This option is available only if PCRE2 has +been compiled with Unicode support (which is the default). .sp PCRE2_UNGREEDY .sp @@ -1957,13 +1963,18 @@ PCRE2 handles caseless matching, and determines whether characters are letters, digits, or whatever, by reference to a set of tables, indexed by character code point. However, this applies only to characters whose code points are less than 256. By default, higher-valued code points never match escapes such as \ew or -\ed. When PCRE2 is built with Unicode support (the default), all characters can -be tested with \ep and \eP, or, alternatively, the PCRE2_UCP option can be set -when a pattern is compiled; this causes \ew and friends to use Unicode property -support instead of the built-in tables. +\ed. +.P +When PCRE2 is built with Unicode support (the default), the Unicode properties +of all characters can be tested with \ep and \eP, or, alternatively, the +PCRE2_UCP option can be set when a pattern is compiled; this causes \ew and +friends to use Unicode property support instead of the built-in tables. +PCRE2_UCP also causes upper/lower casing operations on characters with code +points greater than 127 to use Unicode properties. These effects apply even +when PCRE2_UTF is not set. .P The use of locales with Unicode is discouraged. If you are handling characters -with code points greater than 128, you should either use Unicode support, or +with code points greater than 127, you should either use Unicode support, or use locales, but not try to mix the two. .P PCRE2 contains a built-in set of character tables that are used by default. @@ -3495,7 +3506,10 @@ terminating a \eQ quoted sequence) reverts to no case forcing. The sequences \eu and \el force the next character (if it is a letter) to upper or lower case, respectively, and then the state automatically reverts to no case forcing. Case forcing applies to all inserted characters, including those from -capture groups and letters within \eQ...\eE quoted sequences. +capture groups and letters within \eQ...\eE quoted sequences. If either +PCRE2_UTF or PCRE2_UCP was set when the pattern was compiled, Unicode +properties are used for case forcing characters whose code points are greater +than 127. .P Note that case forcing sequences such as \eU...\eE do not nest. For example, the result of processing "\eUaa\eLBB\eEcc\eE" is "AAbbcc"; the final \eE has no @@ -3923,6 +3937,6 @@ Cambridge, England. .rs .sp .nf -Last updated: 16 February 2020 +Last updated: 24 February 2020 Copyright (c) 1997-2020 University of Cambridge. .fi |