simple_chart/
macros.rs

1
2const EPSILON: f64 = 0.0000001;
3
4type TypeFn = fn(x: f64) -> f64;
5
6pub struct Formula {
7    pub current_x: f64,
8    pub stop: f64,
9    pub start: f64,
10    pub step: f64,
11    pub f: TypeFn,
12}
13
14impl Formula {
15    pub fn new(start: f64, stop: f64, step: f64, f: TypeFn) -> Self {
16        Formula {
17            current_x: start,
18            stop: stop,
19            start: start,
20            step: step,
21            f: f,
22        }
23    }
24}
25
26
27impl Iterator for Formula {
28    type Item = (f64, f64);
29
30    #[inline]
31    fn next(&mut self) -> Option<(f64, f64)> {
32        if self.start < self.stop {
33            if self.current_x < self.stop {
34                let x = self.current_x;
35                self.current_x += self.step;
36                Some((x, (self.f)(x)))
37            } else if (self.stop - self.current_x).abs() < EPSILON {
38                let x = self.stop;
39                self.current_x += self.step;
40                Some((x, (self.f)(x)))
41            } else {
42                None
43            }
44        } else if self.current_x > self.stop {
45            let x = self.current_x;
46            self.current_x -= self.step;
47            Some((x, (self.f)(x)))
48        } else if (self.stop - self.current_x).abs() < EPSILON {
49            let x = self.stop;
50            self.current_x -= self.step;
51            Some((x, (self.f)(x)))
52        } else {
53            None
54        }
55    }
56}
57
58impl Copy for Formula {}
59
60impl Clone for Formula {
61    fn clone(&self) -> Self {
62        *self
63    }
64}
65
66
67#[macro_export]
68macro_rules! formula {
69    ( y($x:ident) = $form:expr, x = [$start:expr, $stop:expr; $step:expr] )
70    =>
71    {
72        {
73        fn f($x: f64) -> f64 { $form }
74        let start = $start as f64;
75        let stop = $stop as f64;
76        let step = $step as f64;
77        Formula::new(start, stop, step, f)
78    }};
79}
80
81
82
83
84#[test]
85fn macros_test() {
86    let points = formula!(y(x) = x.powi(2), x = [1, 1; 0.1]);
87    let pp: Vec<_> = points.collect();
88    assert_eq!(pp, vec![(1f64, 1f64)]);
89}
simple_chart/macros.rs

simple_chart/
macros.rs
