malachite_q/conversion/
mutate_numerator_and_denominator.rs

1// Copyright © 2025 Mikhail Hogrefe
2//
3// This file is part of Malachite.
4//
5// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
6// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
7// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
8
9use crate::Rational;
10use malachite_base::num::arithmetic::traits::{DivExactAssign, Gcd};
11use malachite_nz::natural::Natural;
12
13impl Rational {
14    /// Mutates the numerator of a [`Rational`] using a provided closure, and then returns whatever
15    /// the closure returns.
16    ///
17    /// After the closure executes, this function reduces the [`Rational`].
18    ///
19    /// # Examples
20    /// ```
21    /// use malachite_base::num::basic::traits::One;
22    /// use malachite_nz::natural::Natural;
23    /// use malachite_q::Rational;
24    ///
25    /// let mut q = Rational::from_signeds(22, 7);
26    /// let ret = q.mutate_numerator(|x| {
27    ///     *x -= Natural::ONE;
28    ///     true
29    /// });
30    /// assert_eq!(q, 3);
31    /// assert_eq!(ret, true);
32    /// ```
33    pub fn mutate_numerator<F: FnOnce(&mut Natural) -> T, T>(&mut self, f: F) -> T {
34        let out = f(&mut self.numerator);
35        let gcd = (&self.numerator).gcd(&self.denominator);
36        self.numerator.div_exact_assign(&gcd);
37        self.denominator.div_exact_assign(gcd);
38        if !self.sign && self.numerator == 0 {
39            self.sign = true;
40        }
41        out
42    }
43
44    /// Mutates the denominator of a [`Rational`] using a provided closure, and then returns
45    /// whatever the closure returns.
46    ///
47    /// After the closure executes, this function reduces the [`Rational`].
48    ///
49    /// # Panics
50    /// Panics if the closure sets the denominator to zero.
51    ///
52    /// # Examples
53    /// ```
54    /// use malachite_base::num::basic::traits::One;
55    /// use malachite_nz::natural::Natural;
56    /// use malachite_q::Rational;
57    ///
58    /// let mut q = Rational::from_signeds(22, 7);
59    /// let ret = q.mutate_denominator(|x| {
60    ///     *x -= Natural::ONE;
61    ///     true
62    /// });
63    /// assert_eq!(q.to_string(), "11/3");
64    /// assert_eq!(ret, true);
65    /// ```
66    pub fn mutate_denominator<F: FnOnce(&mut Natural) -> T, T>(&mut self, f: F) -> T {
67        let out = f(&mut self.denominator);
68        assert_ne!(self.denominator, 0);
69        let gcd = (&self.numerator).gcd(&self.denominator);
70        self.numerator.div_exact_assign(&gcd);
71        self.denominator.div_exact_assign(gcd);
72        out
73    }
74
75    /// Mutates the numerator and denominator of a [`Rational`] using a provided closure, and then
76    /// returns whatever the closure returns.
77    ///
78    /// After the closure executes, this function reduces the [`Rational`].
79    ///
80    /// # Panics
81    /// Panics if the closure sets the denominator to zero.
82    ///
83    /// # Examples
84    /// ```
85    /// use malachite_base::num::basic::traits::One;
86    /// use malachite_nz::natural::Natural;
87    /// use malachite_q::Rational;
88    ///
89    /// let mut q = Rational::from_signeds(22, 7);
90    /// let ret = q.mutate_numerator_and_denominator(|x, y| {
91    ///     *x -= Natural::ONE;
92    ///     *y -= Natural::ONE;
93    ///     true
94    /// });
95    /// assert_eq!(q.to_string(), "7/2");
96    /// assert_eq!(ret, true);
97    /// ```
98    pub fn mutate_numerator_and_denominator<F: FnOnce(&mut Natural, &mut Natural) -> T, T>(
99        &mut self,
100        f: F,
101    ) -> T {
102        let out = f(&mut self.numerator, &mut self.denominator);
103        assert_ne!(self.denominator, 0);
104        let gcd = (&self.numerator).gcd(&self.denominator);
105        self.numerator.div_exact_assign(&gcd);
106        self.denominator.div_exact_assign(gcd);
107        if !self.sign && self.numerator == 0 {
108            self.sign = true;
109        }
110        out
111    }
112}
malachite_q/conversion/mutate_numerator_and_denominator.rs

malachite_q/conversion/
mutate_numerator_and_denominator.rs
