diff options
| -rw-r--r-- | doc/src/sgml/func.sgml | 46 |
1 files changed, 32 insertions, 14 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index bc2275c8fee..a79e7c0380b 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -5104,18 +5104,37 @@ SELECT foo FROM regexp_split_to_table('the quick brown fox', '\s*') AS foo; <para> Within a bracket expression, the name of a character class enclosed in <literal>[:</literal> and <literal>:]</literal> stands - for the list of all characters belonging to that class. Standard - character class names are: <literal>alnum</literal>, - <literal>alpha</literal>, <literal>blank</literal>, - <literal>cntrl</literal>, <literal>digit</literal>, - <literal>graph</literal>, <literal>lower</literal>, - <literal>print</literal>, <literal>punct</literal>, - <literal>space</literal>, <literal>upper</literal>, - <literal>xdigit</literal>. These stand for the character classes - defined in - <citerefentry><refentrytitle>ctype</refentrytitle><manvolnum>3</manvolnum></citerefentry>. - A locale can provide others. A character class cannot be used as - an endpoint of a range. + for the list of all characters belonging to that class. A character + class cannot be used as an endpoint of a range. + The <acronym>POSIX</acronym> standard defines these character class + names: + <literal>alnum</literal> (letters and numeric digits), + <literal>alpha</literal> (letters), + <literal>blank</literal> (space and tab), + <literal>cntrl</literal> (control characters), + <literal>digit</literal> (numeric digits), + <literal>graph</literal> (printable characters except space), + <literal>lower</literal> (lower-case letters), + <literal>print</literal> (printable characters including space), + <literal>punct</literal> (punctuation), + <literal>space</literal> (any white space), + <literal>upper</literal> (upper-case letters), + and <literal>xdigit</literal> (hexadecimal digits). + The behavior of these standard character classes is generally + consistent across platforms for characters in the 7-bit ASCII set. + Whether a given non-ASCII character is considered to belong to one + of these classes depends on the <firstterm>collation</firstterm> + that is used for the regular-expression function or operator + (see <xref linkend="collation"/>), or by default on the + database's <envar>LC_CTYPE</envar> locale setting (see + <xref linkend="locale"/>). The classification of non-ASCII + characters can vary across platforms even in similarly-named + locales. (But the <literal>C</literal> locale never considers any + non-ASCII characters to belong to any of these classes.) + In addition to these standard character + classes, <productname>PostgreSQL</productname> defines + the <literal>ascii</literal> character class, which contains exactly + the 7-bit ASCII set. </para> <para> @@ -5126,8 +5145,7 @@ SELECT foo FROM regexp_split_to_table('the quick brown fox', '\s*') AS foo; and end of a word respectively. A word is defined as a sequence of word characters that is neither preceded nor followed by word characters. A word character is an <literal>alnum</literal> character (as - defined by - <citerefentry><refentrytitle>ctype</refentrytitle><manvolnum>3</manvolnum></citerefentry>) + defined by the <acronym>POSIX</acronym> character class described above) or an underscore. This is an extension, compatible with but not specified by <acronym>POSIX</acronym> 1003.2, and should be used with caution in software intended to be portable to other systems. |