Submitted by: @mrotteveel

Relate to CORE5311

Currently Firebird supports a limited form of the character string literal, please add support for the full syntax defined in the SQL standard.

In SQL:2011 character string literal is defined as:

<character string literal> ::=
[ <introducer><character set specification> ]
<quote> [ <character representation>... ] <quote>
[ { <separator> <quote> [ <character representation>... ] <quote> }... ]

This means the following, currently unsupported, string literals should be allowed as well:

* 'ab' 'cd'
* 'ab'/*comment*/'cd'
* 'ab' -- comment and newline
'cd'
* 'ab'
'cd'

etc

See also CORE5311 for binary string literal