build_const-friendly fmt::Debug for fixed-point

shows the raw hex, type, and fractional bits,
in a manner that also compiles as code.

Author: lifning

src/fixed.rs

@@ -241,6 +241,24 @@ macro_rules! impl_common_fixed_ops {
         Self(self.0 >> rhs)
       }
     }
+
+    impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
+      fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        let raw: $t = self.to_bits();
+        write!(
+          f,
+          concat!(
+            "Fixed::<",
+            stringify!($t),
+            ",{}>::from_bits({:#x}_u32 as ",
+            stringify!($t),
+            ")"
+          ),
+          B, raw
+        )
+      }
+    }
+
     impl_trait_op_unit!($t, Not, not);
     impl_trait_op_self_rhs!($t, Add, add);
     impl_trait_op_self_rhs!($t, Sub, sub);
@@ -335,20 +353,6 @@ macro_rules! impl_signed_fixed_ops {
       }
     }
     impl_trait_op_unit!($t, Neg, neg);
-    impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
-      #[inline]
-      fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
-        let whole: $t = self.trunc().to_bits() >> B;
-        let fract: $t = self.fract().to_bits();
-        let divisor: $t = 1 << B;
-        if self.is_negative() {
-          let whole = whole.unsigned_abs();
-          write!(f, "-({whole}+{fract}/{divisor})")
-        } else {
-          write!(f, "{whole}+{fract}/{divisor}")
-        }
-      }
-    }
   };
 }
 impl_signed_fixed_ops!(i8, u8);
@@ -393,15 +397,6 @@ macro_rules! impl_unsigned_fixed_ops {
         Self(self.0 & (<$t>::MAX << B))
       }
     }
-    impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
-      #[inline]
-      fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
-        let whole: $t = self.trunc().to_bits() >> B;
-        let fract: $t = self.fract().to_bits();
-        let divisor: $t = 1 << B;
-        write!(f, "{whole}+{fract}/{divisor}")
-      }
-    }
   };
 }
 impl_unsigned_fixed_ops!(u8);