feat: impl num_traits::Num and num_traits::Signed for Decimal (#11

)
OliverNChalk · Oct 18, 2024 · 4015783 · 4015783
1 parent 18c9eac
commit 4015783
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Showing 3 changed files with 66 additions and 7 deletions.
diff --git a/src/decimal.rs b/src/decimal.rs
@@ -1,6 +1,8 @@
 use std::cmp::Ordering;
 use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssign};
+use std::str::FromStr;
 
+use crate::display::ParseDecimalError;
 use crate::integer::{ScaledInteger, SignedScaledInteger};
 
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
@@ -97,7 +99,47 @@ where
 {
     #[inline]
     fn one() -> Self {
-        Self(I::one() * <I as crate::cheats::Cheats<D>>::SCALING_FACTOR)
+        Self(I::SCALING_FACTOR)
+    }
+}
+
+impl<I, const D: u8> num_traits::Num for Decimal<I, D>
+where
+    I: SignedScaledInteger<D>,
+{
+    type FromStrRadixErr = ParseDecimalError<I>;
+
+    fn from_str_radix(str: &str, radix: u32) -> Result<Self, Self::FromStrRadixErr> {
+        if radix != 10 {
+            return Err(ParseDecimalError::RadixMustBe10);
+        }
+
+        Self::from_str(str)
+    }
+}
+
+impl<I, const D: u8> num_traits::Signed for Decimal<I, D>
+where
+    I: SignedScaledInteger<D>,
+{
+    fn abs(&self) -> Self {
+        Self(self.0.abs())
+    }
+
+    fn abs_sub(&self, other: &Self) -> Self {
+        Self(self.0.abs_sub(&other.0))
+    }
+
+    fn signum(&self) -> Self {
+        Self(self.0.signum())
+    }
+
+    fn is_positive(&self) -> bool {
+        self.0.is_positive()
+    }
+
+    fn is_negative(&self) -> bool {
+        self.0.is_negative()
     }
 }
 
@@ -157,7 +199,7 @@ where
 
     #[inline]
     fn rem(self, rhs: Self) -> Self::Output {
-        Self(self.0 % rhs.0)
+        Self(self.0.checked_rem(&rhs.0).unwrap())
     }
 }
 
@@ -231,9 +273,18 @@ mod tests {
                 #[test]
                 fn [<num_traits_one_ $underlying _ $decimals _add>]() {
                     use num_traits::One;
-                    assert_eq!(Decimal::<$underlying, $decimals>::one(), Decimal::try_from_scaled(1, 0).unwrap());
-                    assert_eq!(Decimal::<$underlying, $decimals>::one(), Decimal::try_from_scaled(10, 1).unwrap());
-                    assert_eq!(Decimal::<$underlying, $decimals>::one(), Decimal::try_from_scaled(100, 2).unwrap());
+                    assert_eq!(
+                        Decimal::<$underlying, $decimals>::one(),
+                        Decimal::try_from_scaled(1, 0).unwrap(),
+                    );
+                    assert_eq!(
+                        Decimal::<$underlying, $decimals>::one(),
+                        Decimal::try_from_scaled(10, 1).unwrap(),
+                    );
+                    assert_eq!(
+                        Decimal::<$underlying, $decimals>::one(),
+                        Decimal::try_from_scaled(100, 2).unwrap(),
+                    );
                 }
 
                 #[test]

diff --git a/src/display.rs b/src/display.rs
@@ -94,6 +94,8 @@ where
     ParseInt(#[from] ParseIntError),
     #[error("Could not parse without precision loss; decimals={0}")]
     PrecisionLoss(usize),
+    #[error("The radix must be 10 in `from_str_radix`")]
+    RadixMustBe10,
 }
 
 #[cfg(test)]

diff --git a/src/integer.rs b/src/integer.rs
@@ -44,6 +44,12 @@ impl<I, const D: u8> ScaledInteger<D> for I where
 {
 }
 
-pub trait SignedScaledInteger<const D: u8>: ScaledInteger<D> + CheckedNeg {}
+pub trait SignedScaledInteger<const D: u8>:
+    ScaledInteger<D> + CheckedNeg + num_traits::Signed
+{
+}
 
-impl<I, const D: u8> SignedScaledInteger<D> for I where I: ScaledInteger<D> + CheckedNeg {}
+impl<I, const D: u8> SignedScaledInteger<D> for I where
+    I: ScaledInteger<D> + CheckedNeg + num_traits::Signed
+{
+}