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I complain about parentheses, and yet I'm building a structure editor[1]. Two complaints about parentheses: - Parentheses obscure the structure of the language

I complain about parentheses, and yet I'm building a structure editor[1]. Two complaints about parentheses: - Parentheses obscure the structure of the language. When different syntax is used for different parts of the language, it's easier to visually scan the code. This is simply because punctuation/arrows/etc. visually stand out more than plain identifiers. - Parenthetical languages have just as much syntax as non-parenthetical languages, it's just a shittier syntax. Try writing (let (x 1) (y 2) (+ x y)) and see what happens: it's a syntax error. Look at the indentation rules in DrRacket: there's let-like, cond-like, etc., because all of those constructs have different syntax. But it all kind of blends together in a sea of parens. This weakness of paren-heavy languages is also their greatest strength, though. Since the syntax is so generic, it's easy to extend, and these language extensions can be indistinguishable from the base language. That's a big deal! BTW, what structure editor would you recommend? Which have you tried? [1] https://github.com/justinpombrio/synless https://github.com/justinpombrio/synless

rscho 2y ago
I run emacs, so I messed around with paredit and friends. I can understand your pov as a professional coder, doing enough coding that you can really master the syntax of your language of choice. I code occasionally for scientific research, and the less syntax I have to remember, the better. Little syntactic constraint in combination with structural editing really is a killer feature in my context.
- justinpombrio 2y ago
  paredit is what I think of as a half-structural editor. It gives you some structural shortcuts, but the cursor is still on a character instead of on a node, IIRC. My bet (that I've spent a lot of time building an editor for) is that the big gains will come when the cursor is never on text, always on an AST node. > the less syntax I have to remember, the better Part of my point is that parenthetical languages don't actually have that much less syntax. You have to remember one of these two syntaxes: let x = 1; let y = 2; do_stuff (let ((x 1) (y 2)) do_stuff) Now you say that there's a lot more possible variation in the first case; it could be: let x = 1; # Rust var x = 1; # JS x=1 # bash And I point out that there's a lot of possible variation in the second case too: (define x 1) (define x 2) do_stuff (let (x 1) (y 2) do_stuff) (let x 1 (let y 2 do_stuff)) There is less syntax with parens. But it's not zero syntax, and you still need to memorize it.

rscho 2y ago

I run emacs, so I messed around with paredit and friends. I can understand your pov as a professional coder, doing enough coding that you can really master the syntax of your language of choice. I code occasionally for scientific research, and the less syntax I have to remember, the better. Little syntactic constraint in combination with structural editing really is a killer feature in my context.

justinpombrio 2y ago
paredit is what I think of as a half-structural editor. It gives you some structural shortcuts, but the cursor is still on a character instead of on a node, IIRC. My bet (that I've spent a lot of time building an editor for) is that the big gains will come when the cursor is never on text, always on an AST node. > the less syntax I have to remember, the better Part of my point is that parenthetical languages don't actually have that much less syntax. You have to remember one of these two syntaxes: let x = 1; let y = 2; do_stuff (let ((x 1) (y 2)) do_stuff) Now you say that there's a lot more possible variation in the first case; it could be: let x = 1; # Rust var x = 1; # JS x=1 # bash And I point out that there's a lot of possible variation in the second case too: (define x 1) (define x 2) do_stuff (let (x 1) (y 2) do_stuff) (let x 1 (let y 2 do_stuff)) There is less syntax with parens. But it's not zero syntax, and you still need to memorize it.