fasteval3 3.0.1

Fast evaluation of algebraic expressions
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

pub(crate) mod common;

use common::assert_error_margin;

use fasteval3::ez_eval;

#[test]
fn empty() {
    let mut ns = fasteval3::EmptyNamespace;

    let val = ez_eval("1 + 1", &mut ns).unwrap();
    assert_error_margin(val, 2.0);
}

#[test]
fn str_to_f64() {
    {
        let mut ns = fasteval3::StringToF64Namespace::new();
        ns.insert(String::from("a"), 1.11);
        ns.insert(String::from("b"), 2.22);

        let val = ez_eval("a + b + 1", &mut ns).unwrap();
        assert_error_margin(val, 4.33);
    }

    {
        let mut ns = fasteval3::StrToF64Namespace::new();
        ns.insert("a", 1.11);
        ns.insert("b", 2.22);

        let val = ez_eval("a + b + 1", &mut ns).unwrap();
        assert_error_margin(val, 4.33);
    }
}

#[test]
fn str_to_cb() {
    {
        let mut ns = fasteval3::StringToCallbackNamespace::new();
        ns.insert(String::from("a"), Box::new(|args| args[0]));
        ns.insert(String::from("b"), Box::new(|args| args[0] * 2.0));

        let val = ez_eval("a(1.11) + b(1.11) + 1", &mut ns).unwrap();
        assert_error_margin(val, 4.33);
    }

    {
        let mut ns = fasteval3::StrToCallbackNamespace::new();
        ns.insert("a", Box::new(|args| args[0]));
        ns.insert("b", Box::new(|args| args[0] * 2.0));

        let val = ez_eval("a(1.11) + b(1.11) + 1", &mut ns).unwrap();
        assert_error_margin(val, 4.33);
    }
}

#[test]
fn layered_str_to_f64() {
    let mut ns = fasteval3::LayeredStringToF64Namespace::new();
    let mut layer0 = fasteval3::StringToF64Namespace::new();
    layer0.insert(String::from("a"), 1.11);
    layer0.insert(String::from("b"), 2.22);
    ns.push(layer0);

    let val = ez_eval("a + b + 1", &mut ns).unwrap();
    assert_error_margin(val, 4.33);

    let mut layer1 = fasteval3::StringToF64Namespace::new();
    layer1.insert(String::from("a"), 11.11);
    ns.push(layer1);

    let val = ez_eval("a + b + 1", &mut ns).unwrap();
    assert_error_margin(val, 14.33);

    ns.pop();

    let val = ez_eval("a + b + 1", &mut ns).unwrap();
    assert_error_margin(val, 4.33);
}

#[test]
fn cb() {
    let mut ns = |name: &str, args: Vec<f64>| match name {
        "a" => Some(1.11),
        "b" => Some(2.22),
        "len" => Some(args.len() as f64),
        _ => None,
    };

    let val = ez_eval("a + b + 1", &mut ns).unwrap();
    assert_error_margin(val, 4.33);
}

#[test]
fn cached_cb() {
    let mut ns = fasteval3::CachedCallbackNamespace::new(|name: &str, args: Vec<f64>| match name {
        "a" => {
            eprintln!("cached_cb: a: This should only be printed once.");
            Some(1.11)
        }
        "b" => Some(2.22),
        "len" => Some(args.len() as f64),
        _ => None,
    });

    let val = ez_eval("a + b + 1", &mut ns).unwrap();
    assert_error_margin(val, 4.33);
    ez_eval("a + b + 1", &mut ns).unwrap();
    ez_eval("a + b + 1", &mut ns).unwrap();
    ez_eval("a + b + 1", &mut ns).unwrap();
    ez_eval("a + b + 1", &mut ns).unwrap();
}

#[test]
fn custom_vector_funcs() {
    let vecs_cell = std::cell::RefCell::new(Vec::<Vec<f64>>::new());

    let mut ns = fasteval3::StrToCallbackNamespace::new();

    ns.insert("x", Box::new(|_args| 2.0));

    ns.insert(
        "vec_store",
        Box::new(|args| {
            let mut vecs = vecs_cell.borrow_mut();
            let index = vecs.len();
            vecs.push(args);
            index as f64
        }),
    );

    ns.insert(
        "vec_sum",
        Box::new(|args| {
            if let Some(index) = args.first() {
                if let Some(v) = vecs_cell.borrow().get(*index as usize) {
                    return v.iter().sum();
                }
            }
            std::f64::NAN
        }),
    );

    let val = ez_eval("vec_sum(vec_store(1.1, x, 3.3)) + vec_sum(0)", &mut ns).unwrap();
    assert_error_margin(val, 12.8);
}