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### Unsupported Regular Expression Patterns

The following regular expression patterns and syntax are not supported in LogScale.

Table: Unsupported Regular Expression Patterns

Pattern Group | Syntax | Notes
--- | --- | ---
`\u{hh..hh}` | The character with hexadecimal value 0xhh..hh |
`\N{`name`}` | The unicode character named `name`. |
`\e` | The escape character |
`\C` | A single byte even in UTF-8 mode |
`[a-d[m-p]]` | Intersecting character ranges (a through d or m through p (union)) |
`[[:`name`:]]` | Named ASCII class inside character class |
`\h` | A horizontal whitespace character |
`\H` | A non-horizontal whitespace character: [^\h] |
`\v` | A vertical whitespace character |
`\V` | A non-vertical whitespace character |
`\p{...}` | POSIX and Unicode character classes | Includes `\p{Lower}`, `\p{Upper}`, `\p{ASCII}`, `\p{Alpha}`, `\p{Digit}`, `\p{Alnum}`, `\p{Punct}`, `\p{Graph}`, `\p{Print}`, `\p{Blank}`, `\p{Xdigit}`, `\p{Space}`, `\p{IsLatin}`, `\p{InGreek}`, `\p{IsLatin}`, `\p{InGreek}`, `\p{Lu}`, `\p{IsAlphabetic}`, `\p{Sc}`, `\P{InGreek}`, `[\p{L}&&[^\p{Lu}]]`
`\b{…}` | A Unicode boundary of specified type |
`\G` | The end of the previous match |
`\R` | Any Unicode linebreak sequence |
`\X` | Any Unicode extended grapheme cluster |
`X?+` | X, once or not at all, possessive |
`X*+` | X, zero or more times, possessive |
`X++` | X, one or more times, possessive |
`X{n}+` | X, exactly n times, possessive |
`\k<name>` | Named backreference |
`X{n,}+` | X, at least n times, possessive |
`X{n,m}+` | X, at least n times but not more than m times, possessive |
`(?<=X)` | X, as a zero-width positive lookbehind |
`(?<!X)` | X, as a zero-width negative lookbehind |
`(?>X)` | X, as an independent, non-capturing (atomic) group. |

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