Support is needed to enable single and double quote characters and linebreaks to appear inside string literals in AQL statements. This would typically be done by quoting, and should probably mimic the quoting rules from ADL.
I assume that it can be made generic enough to support any special character (\t, \r, etc.)
I assume that's what may be needed, but I'd prefer to hear from AQL implementers and users to know what is really needed.
Our (Better by Marand) implementation currently supports backslash to escape the next character, whatever it is. This makes it possible to have verbatim quotes within quoted text. In theory you could also escape a newline if you can get it reliably over communications channel as one character, but that was not the main intention. We never had the need to have a newline or tab within quoted text in AQL, but I suppose we might want to add that for completeness' sake. I guess we should copy the escaping rules from some well-known example, like Java or Python.