SYMEXPR

symexpr is a Rust libray to build symbolic expression and evaluation.

Installation

cargo add symexpr

Usage

use symexpr::{Context, SymCtx, SymValue, SymUsize};

type Usize = SymUsize;

fn main() {
    let x = &Usize::symbol("a");
    let y = &Usize::constant(4);
    let k = &Usize::constant(2);

    let mut ctx = Context::default();
    ctx.set_symbol("a", 2usize);

    let result = x.eval(&ctx).unwrap();
    assert_eq!(result, 2);

    let result = y.eval(&ctx).unwrap();
    assert_eq!(result, 4);

    let b = x.eq(y);
    let result = b.eval(&ctx).unwrap();
    assert!(!result);

    let b = x.ge(y);
    let result = b.eval(&ctx).unwrap();
    assert!(!result);

    let z = x + y;
    let result = z.eval(&ctx).unwrap();
    assert_eq!(result, 6);

    let c = 3;
    let w = c + z + 2 + k + 3;
    let result = w.eval(&ctx).unwrap();
    assert_eq!(result, 16);
}