Parsing literal strings is deficient.

[WardCunningham]

The current grammar requires literal strings (non-terminal strn) to be quoted with double-quotes. The current implementation has several problems.

• The ch('"') terminal adsorbs trailing whitespace which should not be ignored in a literal string.
• Embedded double-quotes are not correctly recognized even when properly escaped.
• Single-quotes can enclose literal strings too.
• Places an unreasonable cap on the size of literal strings and fails when exceeded.

https://s3.amazonaws.com/artifacts.opencypher.org/M18/railroad/StringLiteral.html