Messy work in progress

src/num.rs

@@ -1,4 +1,5 @@
 //! Numeric Helper Traits
+use std::convert::TryFrom;
 use std::ops::{
     Add, AddAssign, BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Div, DivAssign,
     Mul, MulAssign, Not, Rem, RemAssign, Shl, ShlAssign, Shr, ShrAssign, Sub, SubAssign,
@@ -41,6 +42,15 @@ pub trait Unsigned: Int {
 
     /// Find the least common multiple of two numbers
     fn lcm(a: Self, b: Self) -> Self;
+
+    fn is_signed(self) -> bool;
+}
+
+/// A Trait representing signed integer primitives
+pub trait Signed<U=Unsigned>: Int {
+    fn is_neg(self) -> bool;
+
+    fn to_unsigned<U>(self) -> U;
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -143,9 +153,29 @@ macro_rules! impl_unsigned {
     };
 }
 
-impl_num!(i8, u8, i16, u16, f32, i32, u32, f64, i64, u64, i128, u128, usize);
-impl_int!(i8, u8, i16, u16, i32, u32, i64, u64, i128, u128, usize);
+macro_rules! impl_signed {
+    ($(($type: ty, $un_type: ty)),* ) => {
+        $(
+            impl Signed<U=$un_type> for $type {
+                fn is_neg(self) -> bool {
+                    self < 0
+                }
+
+                fn to_unsigned<U>(self) -> U {
+                    // Converting from signed to unsigned should always be safe
+                    // when using the absolute value, especially since I'm converting
+                    // between the same bit size
+                    <U>::try_from(self).unwrap()
+                }
+            }
+        )*
+    }
+}
+
+impl_num!(i8, u8, i16, u16, f32, i32, u32, f64, i64, u64, i128, u128, isize, usize);
+impl_int!(i8, u8, i16, u16, i32, u32, i64, u64, i128, u128, isize, usize);
 impl_unsigned!(u8, u16, u32, u64, u128, usize);
+impl_signed!((i8,u8),(i16,u16),(i32,u32),(i64,u64),(i128,u128),(isize,usize));
 
 #[cfg(test)]
 mod tests {

src/rational.rs

@@ -12,18 +12,78 @@
 //! * SubAssign
 
 use crate::num::*;
-use std::ops::{Mul, Neg};
+use std::ops::{Add, Div, Mul, Neg, Sub};
 
-#[derive(Debug, Default, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct Frac<T: Unsigned = usize> {
     numer: T,
     denom: T,
     sign: Sign,
 }
 
+#[macro_export]
+macro_rules! frac {
+    ($n:literal / $d:literal) => {
+        Frac::new_conv($n, $d)
+    };
+}
+
+/* macro_rules! impl_from_signed {
+    ($(($in_type: ty, $out_type: ty)),* ) => {
+        $(
+            impl Frac<$in_type> {
+                pub fn new(n: $in_type, d: $in_type) -> Frac<$out_type> {
+                    // Converting from signed to unsigned should always be safe
+                    // when using the absolute value, especially since I'm converting
+                    // between the same bit size
+                    let mut sign = $crate::num::Sign::Positive;
+                    let numer = <$out_type>::try_from(n.abs()).unwrap();
+                    let denom = <$out_type>::try_from(d.abs()).unwrap();
+
+                    if n < 0 {
+                        sign = !sign;
+                    }
+
+                    if d < 0 {
+                        sign = !sign;
+                    }
+
+                    Frac::new_signed(numer, denom, sign)
+                }
+
+                fn new_signed(n: $in_type, d: $in_type, _: $crate::num::Sign) -> Frac<$out_type> {
+                    Self::new(n, d)
+                }
+            }
+        )*
+    };
+}
+impl_from_signed!((i8, u8), (i16, u16), (i32, u32), (i64, u64), (i128, u128), (isize, usize)); */
+
+impl<T: Signed, U: Unsigned> Frac<U> {
+    pub fn new_conv(n: T, d: T) -> Self {
+        // Converting from signed to unsigned should always be safe
+        // when using the absolute value, especially since I'm converting
+        // between the same bit size
+        let mut sign = Sign::Positive;
+        let numer:T::Un = n.to_unsigned();
+        let denom:T::Un = d.to_unsigned();
+
+        if n.is_neg() {
+            sign = !sign;
+        }
+
+        if d.is_neg() {
+            sign = !sign;
+        }
+
+        Self::new(numer, denom, sign)
+    }
+}
+
 impl<T: Unsigned> Frac<T> {
     /// Create a new rational number
-    pub fn new(n: T, d: T) -> Self {
+    pub fn new(n: T, d: T, s: Sign) -> Self {
         if d.is_zero() {
             panic!("Fraction can not have a zero denominator");
         }
@@ -31,18 +91,21 @@ impl<T: Unsigned> Frac<T> {
         Frac {
             numer: n,
             denom: d,
-            sign: Sign::Positive,
+            sign: s,
         }
         .reduce()
     }
 
-    pub fn new_neg(n: T, d: T) -> Self {
-        let mut frac = Frac::new(n, d);
-        frac.sign = Sign::Negative;
-
-        frac
+    /// Determine the output sign given the two input signs
+    fn get_sign(a: Self, b: Self) -> Sign {
+        if a.sign != b.sign {
+            Sign::Negative
+        } else {
+            Sign::Positive
+        }
     }
 
+    /// Convert the fraction to its simplest form
     fn reduce(mut self) -> Self {
         let gcd = T::gcd(self.numer, self.denom);
         self.numer /= gcd;
@@ -58,13 +121,68 @@ impl<T: Unsigned + Mul<Output = T>> Mul for Frac<T> {
     fn mul(self, rhs: Self) -> Self {
         let numer = self.numer * rhs.numer;
         let denom = self.denom * rhs.denom;
+        let sign = Self::get_sign(self, rhs);
 
-        // Figure out the sign
-        if self.sign != rhs.sign {
-            Self::new_neg(numer, denom)
-        } else {
-            Self::new(numer, denom)
+        Self::new_signed(numer, denom, sign)
     }
+}
+
+impl<T: Unsigned + Mul<Output = T>> Div for Frac<T> {
+    type Output = Self;
+
+    fn div(self, rhs: Self) -> Self {
+        let numer = self.numer * rhs.denom;
+        let denom = self.denom * rhs.numer;
+        let sign = Self::get_sign(self, rhs);
+
+        Self::new_signed(numer, denom, sign)
+    }
+}
+
+impl<T: Unsigned + Add<Output = T> + Sub<Output = T> + Mul<Output = T>> Add for Frac<T> {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        let a = self;
+        let b = rhs;
+
+        // If the sign of one input differs,
+        // subtraction is equivalent
+        if self.sign != rhs.sign {
+            if a.numer > b.numer {
+                return a - b
+            } else if a.numer < b.numer {
+                return b - a
+            }
+        }
+
+        // Find a common denominator if needed
+        if a.denom != b.denom {
+            // Let's just use the simplest method, rather than
+            // worrying about reducing to the least common denominator
+            let numer = (a.numer * b.denom) + (b.numer * a.denom);
+            let denom = a.denom * b.denom;
+            let sign = Self::get_sign(a, b);
+
+            return Self::new_signed(numer, denom, sign);
+        }
+
+        let numer = a.numer + b.numer;
+        let denom = self.denom;
+        let sign = Self::get_sign(a, b);
+
+        Self::new_signed(numer, denom, sign)
+    }
+}
+
+impl<T: Unsigned + Sub<Output = T>> Sub for Frac<T> {
+    type Output = Self;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        let a = self;
+        let b = rhs;
+
+        unimplemented!()
     }
 }
 
@@ -85,11 +203,27 @@ mod tests {
 
     #[test]
     fn mul_test() {
-        let frac1 = Frac::new(1u8, 3u8);
-        let frac2 = Frac::new(2u8, 3u8);
+        let frac1 = Frac::new(1u8, 3u8, Sign::Positive);
+        let frac2 = Frac::new(2u8, 3u8, Sign::Positive);
 
-        let expected = Frac::new(2u8, 9u8);
+        let expected = Frac::new(2u8, 9u8, Sign::Positive);
 
         assert_eq!(frac1 * frac2, expected);
     }
+
+    #[test]
+    fn add_test() {
+        assert_eq!(frac!(5u8 / 6), frac!(1 / 3) + frac!(1 / 2));
+    }
+
+    #[test]
+    fn macro_test() {
+        let frac1 = frac!(1u8 / 3);
+        let frac2 = Frac::new(1u8, 3, Sign::Positive);
+        assert_eq!(frac1, frac2);
+
+        let frac1 = -frac!(1u8 / 2);
+        let frac2 = Frac::new(1u8, 2, Sign::Negative);
+        assert_eq!(frac1, frac2);
+    }
 }