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Commite2e46a9

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Fix documentation of regular expression character-entry escapes.
The docs claimed that \uhhhh would be interpreted as a Unicode valueregardless of the database encoding, but it's never been implementedthat way: \uhhhh and \xhhhh actually mean exactly the same thing, namelythe character that pg_mb2wchar translates to 0xhhhh. Moreover we werefalsely dismissive of the usefulness of Unicode code points above FFFF.Fix that.It's been like this for ages, so back-patch to all supported branches.
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‎doc/src/sgml/func.sgml‎

Lines changed: 17 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -4653,7 +4653,7 @@ SELECT foo FROM regexp_split_to_table('the quick brown fox', E'\\s*') AS foo;
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<entry> <literal>\e</> </entry>
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<entry> the character whose collating-sequence name
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is <literal>ESC</>,
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or failing that, the character with octal value 033 </entry>
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or failing that, the character with octal value<literal>033</> </entry>
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</row>
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<row>
@@ -4679,15 +4679,17 @@ SELECT foo FROM regexp_split_to_table('the quick brown fox', E'\\s*') AS foo;
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<row>
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<entry> <literal>\u</><replaceable>wxyz</> </entry>
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<entry> (where <replaceable>wxyz</> is exactly four hexadecimal digits)
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the UTF16 (Unicode, 16-bit) character <literal>U+</><replaceable>wxyz</>
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in the local byte ordering </entry>
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the character whose hexadecimal value is
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<literal>0x</><replaceable>wxyz</>
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</entry>
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</row>
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<row>
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<entry> <literal>\U</><replaceable>stuvwxyz</> </entry>
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<entry> (where <replaceable>stuvwxyz</> is exactly eight hexadecimal
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digits)
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reserved for a hypothetical Unicode extension to 32 bits
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the character whose hexadecimal value is
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<literal>0x</><replaceable>stuvwxyz</>
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</entry>
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</row>
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@@ -4736,6 +4738,17 @@ SELECT foo FROM regexp_split_to_table('the quick brown fox', E'\\s*') AS foo;
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Octal digits are <literal>0</>-<literal>7</>.
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</para>
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<para>
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Numeric character-entry escapes specifying values outside the ASCII range
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(0-127) have meanings dependent on the database encoding. When the
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encoding is UTF-8, escape values are equivalent to Unicode code points,
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for example <literal>\u1234</> means the character <literal>U+1234</>.
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For other multibyte encodings, character-entry escapes usually just
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specify the concatenation of the byte values for the character. If the
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escape value does not correspond to any legal character in the database
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encoding, no error will be raised, but it will never match any data.
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</para>
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<para>
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The character-entry escapes are always taken as ordinary characters.
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For example, <literal>\135</> is <literal>]</> in ASCII, but

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