femtolisp: A lightweight, robust, scheme-like Lisp implementation(github.com)
73 pointsby tosh6 hours ago3 comments
  • embedding-shapean hour ago
    Slightly unrelated, but you take what (hn item) you can get: What is the smallest lisp (semantically/language-wise) people know, that could be used for implementing itself? Theoretical or practical/"real" is less relevant, mostly just curious. So far, it seems Bel (by pg) might get the closest, but can't claim to be an expert, surely could be something smaller out there?
  • borodi4 hours ago
    Fun fact, Julia's parser and part of its compiler are implemented in femtolisp, and you can access it using a not so secret option in the Julia CLI.
    • eigenspace4 hours ago
      We are slowly moving on replacing this stuff with implementations written in pure julia.

      Currently the femtolisp parser is only used during bootstrapping the core systems so that we can parse the pure-julia parser and then we switch over to the julia parser. The same process is now happening with the femtolisp implementation of the lowering pass.

      • tokai4 hours ago
        So Julia will no longer be a LISP? :'(
        • eigenspace3 hours ago
          Having some components written in lisp was never the lispy part of julia. The thing that makes julia lispy is its semantics and features.
          • tokai3 hours ago
            I agree. Was trying a tongue in cheek comment about how the Julia/LISP discussion over the years often would have someone point to julia --lisp as an argument for Julia being a LISP dialect.
    • markkitti3 hours ago

          $ julia --lisp
    ;  _
    ; |_ _ _ |_ _ |  . _ _
    ; | (-||||_(_)|__|_)|_)
    ;-------------------|-----    ------------------------------    -----------------------
    > (+ 1 2)
    3
  • danlitt3 hours ago
    Interesting! This seems superficially related to GNU Mes[1], although I imagine femtolisp does not require its small source to be written in a "simple" dialect of C.

    [1]: https://www.gnu.org/software/mes/