fasteval 0.2.4

Fast evaluation of algebraic expressions
Documentation 
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use fasteval::{Evaler, Error, Slab, Cached, EmptyNamespace, CachedCallbackNamespace, Parser};
use fasteval::bool_to_f64;

use std::mem;
use std::collections::{BTreeMap, BTreeSet};

#[test]
fn eval() {
    let mut slab = Slab::new();
    let mut ns = BTreeMap::<String,f64>::new();
    ns.insert("x".to_string(), 1.0);
    ns.insert("y".to_string(), 2.0);
    ns.insert("z".to_string(), 3.0);

    // Sanity check:
    assert_eq!(Parser::new().parse("3+3-3/3", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns).unwrap(), 5.0);

    assert_eq!(Parser::new().parse("x+y+z", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns).unwrap(), 6.0);

    assert_eq!(Parser::new().parse("x+y+z+a", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns), Err(Error::Undefined("a".to_string())));
}

#[test]
fn aaa_util() {
    assert_eq!(bool_to_f64!(true), 1.0);
    assert_eq!(bool_to_f64!(false), 0.0);
}

#[test]
fn aaa_aaa_sizes() {
    eprintln!("sizeof(Slab):{}", mem::size_of::<Slab>());
    assert!(mem::size_of::<Slab>()<2usize.pow(18));  // 256kB

}

#[test]
fn aaa_aab_single() {
    let mut slab = Slab::new();
    let mut ns = EmptyNamespace;
    assert_eq!(Parser::new().parse("123.456", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns).unwrap(), 123.456f64);
}

#[test]
fn aaa_basics() {
    let mut slab = Slab::new();

    assert_eq!(
        Parser::new().parse("12.34 + 43.21 + 11.11", &mut slab.ps).unwrap().from(&slab.ps).var_names(&slab),
        BTreeSet::new());

    let mut ns = EmptyNamespace;
    assert_eq!(
        Parser::new().parse("12.34 + 43.21 + 11.11", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(66.66));
    assert_eq!(
        Parser::new().parse("12.34 + 43.21 - 11.11", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(44.44));
    assert_eq!(
        Parser::new().parse("11.11 * 3", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(33.33));
    assert_eq!(
        Parser::new().parse("33.33 / 3", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(11.11));
    assert_eq!(
        Parser::new().parse("33.33 % 3", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.3299999999999983));
    assert_eq!(
        Parser::new().parse("1 and 2", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.0));
    assert_eq!(
        Parser::new().parse("1 && 2", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.0));
    assert_eq!(
        Parser::new().parse("2 or 0", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.0));
    assert_eq!(
        Parser::new().parse("2 || 0", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.0));
    assert_eq!(
        Parser::new().parse("1 > 0", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(1.0));
    assert_eq!(
        Parser::new().parse("1 < 0", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.0));

    assert_eq!(
        Parser::new().parse("+5.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(5.5));
    assert_eq!(
        Parser::new().parse("-5.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(-5.5));
    assert_eq!(
        Parser::new().parse("!5.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.0));
    assert_eq!(
        Parser::new().parse("!0", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(1.0));
    assert_eq!(
        Parser::new().parse("(3 * 3 + 3 / 3)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(10.0));
    assert_eq!(
        Parser::new().parse("(3 * (3 + 3) / 3)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(6.0));

    assert_eq!(
        Parser::new().parse("4.4 + -5.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(-1.0999999999999996));
    assert_eq!(
        Parser::new().parse("4.4 + +5.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(9.9));

    assert_eq!(
        Parser::new().parse("x + 1", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Err(Error::Undefined("x".to_string())));

    let mut ns = CachedCallbackNamespace::new(|_,_| Some(3.0));
    assert_eq!(
        Parser::new().parse("x + 1", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.0));

    assert_eq!(
        Parser::new().parse("1.2 + int(3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.2));
    assert_eq!(
        Parser::new().parse("1.2 + ceil(3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(5.2));
    assert_eq!(
        Parser::new().parse("1.2 + floor(3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.2));
    assert_eq!(
        Parser::new().parse("1.2 + abs(-3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.6));
    assert_eq!(
        Parser::new().parse("1.2 + log(1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(1.2));
    assert_eq!(
        Parser::new().parse("1.2 + log(10)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.2));
    assert_eq!(
        Parser::new().parse("1.2 + log(0)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(std::f64::NEG_INFINITY));
    assert!(Parser::new().parse("1.2 + log(-1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns).unwrap().is_nan());
    assert_eq!(
        Parser::new().parse("1.2 + round(3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.2));
    assert_eq!(
        Parser::new().parse("1.2 + round(0.5, 3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.7));
    assert_eq!(
        Parser::new().parse("1.2 + round(-3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(-1.8));
    assert_eq!(
        Parser::new().parse("1.2 + round(0.5, -3.4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(-2.3));
    assert_eq!(
        Parser::new().parse("1.2 + min(1,2,0,3.3,-1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.19999999999999996));
    assert_eq!(
        Parser::new().parse("1.2 + min(1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.2));
    assert_eq!(
        Parser::new().parse("1.2 + max(1,2,0,3.3,-1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(4.5));
    assert_eq!(
        Parser::new().parse("1.2 + max(1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.2));

    assert_eq!(
        Parser::new().parse(r#"12.34 + print ( 43.21, "yay" ) + 11.11"#, &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(66.66));

    assert_eq!(
        Parser::new().parse("e()", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.718281828459045));
    assert_eq!(
        Parser::new().parse("pi()", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(3.141592653589793));

    assert_eq!(
        Parser::new().parse("sin(pi()/2)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(1.0));
    assert_eq!(
        Parser::new().parse("cos(pi()/2)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.00000000000000006123233995736766));
    assert_eq!(
        Parser::new().parse("tan(pi()/4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.9999999999999999));
    assert_eq!(
        Parser::new().parse("asin(1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(1.5707963267948966));
    assert_eq!(
        Parser::new().parse("acos(0)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(1.5707963267948966));
    assert_eq!(
        Parser::new().parse("atan(1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.7853981633974483));
    assert_eq!(
        Parser::new().parse("sinh(pi()/2)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.3012989023072947));
    assert_eq!(
        Parser::new().parse("cosh(pi()/2)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(2.5091784786580567));
    assert_eq!(
        Parser::new().parse("tanh(pi()/4)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(0.6557942026326724));
}


//// Commented out until we bring CachedLayeredNamespace back.
// #[derive(Debug)]
// struct TestEvaler;
// impl Evaler for TestEvaler {
//     fn _var_names(&self, _slab:&Slab, _dst:&mut BTreeSet<String>) {}
//     fn eval(&self, _slab:&Slab, ns:&mut impl EvalNamespace) -> Result<f64,Error> {
//         match ns.lookup("x", vec![], &mut String::new()) {
//             Some(v) => Ok(v),
//             None => Ok(1.23),
//         }
//     }
// }
// 
// #[test]
// fn aaa_evalns_basics() {
//     let slab = Slab::new();
//     let mut ns = CachedLayeredNamespace::new(|_,_| Some(5.4321));
//     assert_eq!({ ns.push(); let out=TestEvaler{}.eval(&slab, &mut ns); ns.pop(); out }.unwrap(), 5.4321);
//     ns.create_cached("x".to_string(),1.111).unwrap();
//     assert_eq!({ ns.push(); let out=TestEvaler{}.eval(&slab, &mut ns); ns.pop(); out }.unwrap(), 1.111);
// }

#[test]
fn corners() {
    let mut slab = Slab::new();
    let mut ns = EmptyNamespace;
    assert_eq!(
        format!("{:?}", Parser::new().parse("(-1) ^ 0.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns)),
        "Ok(NaN)");
}

fn my_evalns_cb_function(_:&str, _:Vec<f64>) -> Option<f64> { None }
#[test]
fn evalns_cb_ownership() {
    let _ns = CachedCallbackNamespace::new(my_evalns_cb_function);
    let _ns = CachedCallbackNamespace::new(my_evalns_cb_function);
    // Conclusion: You can pass a function pointer into a function that receives ownership.

    let closure = |_:&str, _:Vec<f64>| None;
    let _ns = CachedCallbackNamespace::new(closure);
    let _ns = CachedCallbackNamespace::new(closure);

    let x = 1.0;
    let closure = |_:&str, _:Vec<f64>| Some(x);
    let _ns = CachedCallbackNamespace::new(closure);
    let _ns = CachedCallbackNamespace::new(closure);

    let mut x = 1.0;
    let closure = |_:&str, _:Vec<f64>| {
        x+=1.0;
        Some(x)
    };
    let _ns = CachedCallbackNamespace::new(closure);
    //let _ns = CachedCallbackNamespace::new(closure);  // Not allowed.

    // Conclusion: Functions and Closures that don't mutate state are effectively Copy.
    //             Closures that mutate state aren't Copy.
    //             Note that the argument type (FnMut vs Fn) doesn't actually matter,
    //             just the implementation matters!
}

#[test]
fn custom_func() {
    let mut slab = Slab::new();
    let mut ns = CachedCallbackNamespace::new(|name,args| {
        eprintln!("In CB: {}",name);
        match name {
            "x" => Some(1.0),
            "y" => Some(2.0),
            "z" => Some(3.0),
            "foo" => {
                Some(args.get(0).unwrap_or(&std::f64::NAN)*10.0)
            }
            "bar" => {
                Some(args.get(0).unwrap_or(&std::f64::NAN) + args.get(1).unwrap_or(&std::f64::NAN))
            }
            _ => None,
        }
    });
    assert_eq!(
        Parser::new().parse("x + 1.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(2.5));

    assert_eq!(
        Parser::new().parse("x() + 1.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(2.5));

    assert_eq!(
        Parser::new().parse("x(1,2,3) + 1.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(2.5));

    eprintln!("I should see TWO x lookups, 1 y, and 1 z:");
    assert_eq!(
        Parser::new().parse("x(x,y,z) + 1.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(2.5));

    eprintln!("I should see TWO x lookups:");
    assert_eq!(
        Parser::new().parse("x(x,x,x) + 1.5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(2.5));

    eprintln!("I should see TWO x lookups:");
    assert_eq!(
        Parser::new().parse("x(1.0) + x(1.1) + x(1.0) + x(1.1)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(4.0));

    eprintln!("---------------------------");

    assert_eq!(
        Parser::new().parse("foo(1.23)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(12.3));

    assert_eq!(
        Parser::new().parse("bar(1.23, 3.21)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns}),
        Ok(4.4399999999999995));

    assert_eq!(
        format!("{:?}", Parser::new().parse("bar(1.23)", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, {ns.cache_clear(); &mut ns})),
        "Ok(NaN)");
}

#[test]
#[cfg(feature="unsafe-vars")]
fn unsafe_var() {
    let mut slab = Slab::new();

    let mut ua = 1.23;
    let mut ub = 4.56;
    unsafe {
        slab.ps.add_unsafe_var("ua".to_string(), &ua);
        slab.ps.add_unsafe_var("ub".to_string(), &ub);
    }

    let mut ns = EmptyNamespace;

    assert_eq!(
        Parser::new().parse("ua + ub + 5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(10.79));

    ua+=1.0;
    ub+=2.0;
    assert_eq!(
        Parser::new().parse("ua + ub + 5", &mut slab.ps).unwrap().from(&slab.ps).eval(&slab, &mut ns),
        Ok(13.79));

    let _ = (ua,ub);  // Silence compiler warnings about variables not being read.
}