zypeh

use std::boxed::Box;

#[derive(Clone, Debug)]
enum Expr {
    VAR(String),
    APP { func: Box<Expr>, arg: Box<Expr> },
    LAM { arg: String, body: Box<Expr> },
}

type Env = Vec<(String, Val)>;

zypeh

benchmarked sexp/fpbasic
time                 3.193 ms   (3.073 ms .. 3.357 ms)
                     0.989 R²   (0.978 R² .. 0.998 R²)
mean                 2.960 ms   (2.928 ms .. 3.023 ms)
std dev              145.1 μs   (89.51 μs .. 250.5 μs)
variance introduced by outliers: 28% (moderately inflated)

benchmarked sexp/fpstateful
time                 3.417 ms   (3.346 ms .. 3.471 ms)
                     0.997 R²   (0.995 R² .. 0.999 R²)