Regarding the "whitespace thing" I think they're doing themselves a disservice by not starting with predefined rules allowing them to use whitespace delimited words and deferring showing how you can bootstrap to that point until later.
In general, show more of what is possible in a more accessible way first, before presenting "line noise".
Overall that document would be helped by some editing to bring out more of what a reader who haven't spent months thinking about this will find interesting first.
ding! I think the bootstrapping code might've bitten us. Of course there's no
practical reason why we _needed_ to not have the delim flag flipped and a couple
of delimiters defined, but there's a conceptual symmetry in it being the way
it is. Still, I agree in large part with your point.
It seems as though you've read the entire article and understood a decent
portion of it. I'm impressed because I think I explained this suboptimally.
I think it's fine to show that you can do it, I think the main thing is to flip the order a bit.
E.g. "here's a cool thing thing we can do <demonstrate the outcome of significantly changing a readable syntax>" to hook people, "here's how <show how you change syntax with higher level helpers>", "and if you really want to know how to bootstrap this from basics <here comes the linenoise>".
Maybe compare how e.g. Forth is often introduced, with how people describe bootstrapping of a simplistic Forth like Jonesforth or Sectorforth [2]. Showing people how they can define their own words and it fundamentally changes how they work with the language afterwards is cool to a lot of people who have no interest in details like how you an implement even numbers with a minimal set of primitives (e.g. Sectorforth relies on that - it doesn't have builtin numbers[3]).
Both are interesting to me, but I'm weird, and I think for most people it'd be easier to maintain their interest if those two aspects are either separate articles or at least if the bootstrapping is relegated to a standalone section they're clearly told they can skip.
[3] The Sectorforth Hello world defines every numeric constant it needs like this:
: -1 ( x -- x -1 ) dup dup nand dup dup nand and ;
: 0 -1 dup and ;
: 1 -1 dup + dup and ;
: 2 1 1 + ;
: 4 2 2 + ;
: 6 2 4 + ;
Which is fun if you're a language geek. Not so convincing if you want to know if Forth is fort you [EDIT: That mistake was wholly unintentional, but I'll leave it].
In general, show more of what is possible in a more accessible way first, before presenting "line noise".
Overall that document would be helped by some editing to bring out more of what a reader who haven't spent months thinking about this will find interesting first.