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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181

#[macro_export]
macro_rules! units {
    ($($i: ident), +) => {
        #[derive(Debug, PartialEq, PartialOrd, Ord, Clone, Copy, Eq)]
        #[allow(non_camel_case_types)]
        pub enum Units {
            $(
                $i,
            )+
        }

        impl unitary::Measurement for Units {}
    };
}

#[derive(Debug, Clone)]
pub struct Qty<T: Measurement>(pub f64, pub Vec<(T, f64)>);

#[macro_export]
macro_rules! qty {
    ($i: expr; $t: ident) => {
        unitary::Qty($i, vec![(Units::$t, 1.0)]);
    };
}

use std::fmt::{self, Debug};

pub trait Measurement: PartialEq + Ord + Copy + Debug + Eq {}

use std::ops::{Add, Div, Mul, Sub};

impl<T: Measurement> Div<Qty<T>> for Qty<T> {
    type Output = Qty<T>;

    fn div(self, rhs: Qty<T>) -> Qty<T> {
        let mut num = self.1;
        let mut denom = rhs.1.into_iter().map(|(x, y)| (x, -y)).collect();
        num.append(&mut denom);
        num.sort_by_key(|a| a.0);
        let num = get_units(&num);

        Qty(self.0 / rhs.0, num)
    }
}

impl<T: Measurement> Div<f64> for Qty<T> {
    type Output = Qty<T>;

    fn div(self, rhs: f64) -> Qty<T> {
        Qty(self.0 / rhs, self.1)
    }
}

impl<T: Measurement> Mul<Qty<T>> for Qty<T> {
    type Output = Qty<T>;

    fn mul(self, rhs: Qty<T>) -> Qty<T> {
        let mut num = self.1;
        let mut denom = rhs.1;
        num.append(&mut denom);
        num.sort_by_key(|a| a.0);
        let num = get_units(&num);

        Qty(self.0 * rhs.0, num)
    }
}

impl<T: Measurement> Mul<f64> for Qty<T> {
    type Output = Qty<T>;

    fn mul(self, rhs: f64) -> Qty<T> {
        Qty(self.0 * rhs, self.1)
    }
}

impl<T: Measurement> Add<Qty<T>> for Qty<T> {
    type Output = Qty<T>;

    fn add(self, rhs: Qty<T>) -> Qty<T> {
        if self.1 == rhs.1 {
            Qty(self.0 + rhs.0, self.1)
        } else {
            panic!("Differing Units")
        }
    }
}

impl<T: Measurement> Sub<Qty<T>> for Qty<T> {
    type Output = Qty<T>;

    fn sub(self, rhs: Qty<T>) -> Qty<T> {
        if self.1 == rhs.1 {
            Qty(self.0 - rhs.0, self.1)
        } else {
            panic!("Differing Units")
        }
    }
}

impl<T: Measurement> Into<f64> for Qty<T> {
    fn into(self) -> f64 {
        if self.1 == [] {
            self.0
        } else {
            panic!("Cannot unwrap non-zero units")
        }
    }
}

use std::f64;

impl<T: Measurement> fmt::Display for Qty<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "{} {}",
            self.0,
            self.1
                .clone()
                .into_iter()
                .map(|(unit, coef)| if (coef - 1.0).abs() < f64::EPSILON {
                    format!("⋅{:?}", unit)
                } else {
                    format!("⋅({:?}^{})", unit, coef)
                })
                .collect::<String>()
        )
    }
}

fn get_units<T: Measurement>(data: &[(T, f64)]) -> Vec<(T, f64)> {
    let mut single = data.to_owned();
    single.dedup_by_key(|a| a.0);
    let mut new = Vec::new();
    for &(t, _v) in &single {
        let mut acc = 0.0;
        for &(d, v) in data {
            if d == t {
                acc += v;
            }
        }
        if acc != 0.0 {
            new.push((t, acc));
        }
    }
    new
}

type Pair<T> = (Vec<(T, f64)>, (T, f64));

fn get_units_or_alias<T: Measurement>(data: Vec<(T, f64)>, aliases: &[Pair<T>]) -> Vec<(T, f64)> {
    for &(ref i, ref j) in aliases {
        if &data == i {
            return vec![*j];
        }
    }
    data
}

impl<T: Measurement> Qty<T> {
    pub fn powf(self, rhs: f64) -> Qty<T> {
        Qty(
            self.0.powf(rhs),
            self.1
                .into_iter()
                .map(|(x, y)| {
                    let c = y < 1.0;
                    let mut a = y.abs().powf(rhs);
                    if c {
                        a *= -1.0
                    }
                    (x, a)
                })
                .collect(),
        )
    }

    pub fn update(&mut self, aliases: &[Pair<T>]) {
        self.1 = get_units_or_alias(self.1.clone(), aliases)
    }
}