Substitute: add support for $& $` $' $_ and \b \v #491
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The
$&replacement, and$`and$'are common sequences for$0, and "left of $0" / "right of $0" respectively. Perl supports these, so PCRE2 surely should.The
$_is less common but supported by some engines.Finally, very very minor:
The
\bescape is supported by Perl, so we should add it too.The
\vescape is there for completeness - it's not apparently supported by Perl, but many other dialects such as JavaScript or .NET use this C-inspired escape sequence for "vertical tab". It's obviously not possible to support this in patterns, but in the replacement string I can't see a reason not support it.