Show HN: Sexprs – Lisp dialect written in Rust

(github.com)

21 points | by gfalcao 4 days ago ago

3 comments

  • uncircle 5 hours ago ago

    The code in the screenshot/asciinema isn't s-expr by any common conception of the term, or as a Lisp would parse it.

      (flatten '( '(a '( b)) '( c   d)))
    
    That argument to flatten is in fact [macroexpanding manually, forgive errors]

      '((quote (a (quote (b)))) (quote c d))
    
    which flattens to

      '(quote a quote b quote c d)
    
    ---

    Parsing sexprs is quite easy, no need to use a complex parser generator. The core of parsing sexprs is you have a "read_list" function, which accumulates values until it finds a ')', and whenever you encounter a '(' character, you recurse into that same read_list function. You don't even need a lexer.

    Also, this is divided in 8 crates for some reason... don't take this the wrong way, but is it the result of vibe coding?

    • mplanchard 4 hours ago ago

      Doesn’t seem vibe coded to me. The crates aren’t unreasonable: data structures, parser, formatter, repl, “util,” some proc macros (which have to be in a separate crate in rust), and a VM.

  • junon 8 hours ago ago

    Haha, funny. I also wrote something similar for working with KiCad files, naming it Sexprs, also in Rust. I was worried someone had found it and posted it here.

    Is there a way to modify and re-emit them at runtime? Seems neat, but the readme is lacking.