Consider adding RDF lists to HOWL

[jamesaoverton]

The RDF spec defines rdf:first and rdf:rest predicates for building linked lists. This is the main way that people specify ordered information in RDF. I don't actually see RDF lists much in the wild. Some OWL constructs use them. They aren't yet included in HOWL, but maybe they should be.

(I guess there are other RDF container types.)

In the Turtle spec these are called collections and the syntax uses parentheses:

@prefix : <http://example.org/foo> .
# the object of this triple is the RDF collection blank node
:subject :predicate ( :a :b :c ) .

RDF lists could be one sort of HOWL expression. We could just use the Turtle syntax, but it wouldn't support labels, so think there should be a special HOWL syntax for lists.

The HOWL syntax for lists should be line-based, and allow for different sorts of literals. The list markers could follow Markdown conventions. Here's an idea:

subject
predicate TYPE rdf:List:>>
  1: Foo
  2 LANGUAGE fr: La foo
  3 TYPE integer: 100
  4:> ex:foo
  5:>> some expression