The S-Expression parser works fine for simple S-Expressions,
but one can't parse quoted expressions ('hello) or quasi-quoted expressions using it,
also vectors (#(hello)) are not supported.

I understand, that they aren't part of the real bare bone S-Expression thing,
but they are supported by a big majority of LISPs out there.

Implementing them directly would break compatibility, but they could be implemented using a special flag.

SXP.read "(hello 'quoted #(world))", [:vector, :quote]     #=> [:hello, [:quote, :quoted], [:vector, :world]]