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Having said that even with an explicit language hint (<!-- language: lang-sql -->
) a \
is normally not used as an escape, though it is not rendered as a string literal.
select '\'
To take a portion of your example (this is quite difficult to see on my screen) it's still almost working
select ('^(.*?)(<.*?>)$', '\'||pos), blah
It's only the addition of more single quotes that causes it to break
select ('^(.*?)(<.*?>)$', '\'||pos)
'blah' blah