Logo lets you leave out parentheses most of the time, except to use rest arguments or force grouping. For example:
? print list sum 0 1 2
1 2
? (print (list 1 2 3 (sum 1 1 1 1)))
1 2 3 4
? print (list 1 2 sum 1 2 4)
1 2 3 4
? print 1 + 2 * 3 + 4
11I love Logo! Advanced Logo by Michael Friendly is one of my programming books.
Logo came very close to TN and ETNs but adding the parens and other visible syntax I believe was a design mistake. It's not obvious, but when working with large programs in 2 and 3 dimensions (only possible with parens free lisp, or ETNs as we call them), you gain tremendous productivity benefits
>Are you aware of other identical or near identical implementations?:
srfi-110, srfi-119.
So far I'm only aware of one previous discovery--https://srfi.schemers.org/srfi-49/srfi-49.html--, which nsajko pointed me to a couple weeks ago, (https://news.ycombinator.com/item?id=14606595). Are you aware of other identical or near identical implementations? The tiniest details matter here. I'd be very interested in more.
> but somehow this dream language never approaches even Lisp in popularity.
Agreed! That's what I'm hoping to help change. It's going to be a long slog, but I'm very confident the math works out and it's going to happen. The tooling needs to be built to take advantage of the properties of these languages before they will catch on. But once that happens, I think we're in for a whole new world in programming.