feat: make more methods const

CHANGELOG.md

@@ -13,7 +13,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-- `classify_bits`, `is_infinity_bits` are now `const`
+- Make the following methods `const` on all float types:
+  - `abs()`
+  - `classify()`
+  - `classify_bits()`
+  - `copysign()`
+  - `is_finite()`
+  - `is_infinite()`
+  - `is_infinity_bits()`
+  - `is_nan()`
+  - `is_normal()`
+  - `signum()`
 
 ## [0.1.2](https://github.com/LDeakin/microfloat/releases/tag/v0.1.2) - 2026-04-29
 

src/formats.rs

@@ -315,27 +315,27 @@ macro_rules! define_format {
             }
 
             /// Returns `true` if this value is NaN.
-            pub fn is_nan(self) -> bool {
+            pub const fn is_nan(self) -> bool {
                 self.0.is_nan()
             }
 
             /// Returns `true` if this value is positive or negative infinity.
-            pub fn is_infinite(self) -> bool {
+            pub const fn is_infinite(self) -> bool {
                 self.0.is_infinite()
             }
 
             /// Returns `true` if this value is neither infinite nor NaN.
-            pub fn is_finite(self) -> bool {
+            pub const fn is_finite(self) -> bool {
                 self.0.is_finite()
             }
 
             /// Returns `true` if this value is finite, nonzero, and not subnormal.
-            pub fn is_normal(self) -> bool {
+            pub const fn is_normal(self) -> bool {
                 self.0.is_normal()
             }
 
             /// Returns the floating point category of this value.
-            pub fn classify(self) -> core::num::FpCategory {
+            pub const fn classify(self) -> core::num::FpCategory {
                 self.0.classify()
             }
 
@@ -354,19 +354,19 @@ macro_rules! define_format {
             }
 
             /// Returns a value with the magnitude of `self` and the sign of `sign`.
-            pub fn copysign(self, sign: Self) -> Self {
+            pub const fn copysign(self, sign: Self) -> Self {
                 Self(self.0.copysign(sign.0))
             }
 
             /// Returns a number representing the sign of `self`.
             ///
             /// NaN and zero values are returned unchanged.
-            pub fn signum(self) -> Self {
+            pub const fn signum(self) -> Self {
                 Self(self.0.signum())
             }
 
             /// Returns the absolute value of `self`.
-            pub fn abs(self) -> Self {
+            pub const fn abs(self) -> Self {
                 Self(self.0.abs())
             }
 

src/micro.rs

@@ -78,23 +78,24 @@ impl<F: Format> MicroFloat<F> {
         f64::from(self.to_f32())
     }
 
-    pub fn is_nan(self) -> bool {
+    pub const fn is_nan(self) -> bool {
         classify_bits::<F>(self.bits).is_nan
     }
 
-    pub fn is_infinite(self) -> bool {
+    pub const fn is_infinite(self) -> bool {
         classify_bits::<F>(self.bits).is_infinite
     }
 
-    pub fn is_finite(self) -> bool {
+    pub const fn is_finite(self) -> bool {
         !self.is_nan() && !self.is_infinite()
     }
 
-    pub fn is_normal(self) -> bool {
-        matches!(self.classify(), FpCategory::Normal)
+    pub const fn is_normal(self) -> bool {
+        let class = classify_bits::<F>(self.bits);
+        !class.is_nan && !class.is_infinite && !class.is_zero && !class.is_subnormal
     }
 
-    pub fn classify(self) -> FpCategory {
+    pub const fn classify(self) -> FpCategory {
         let class = classify_bits::<F>(self.bits);
         if class.is_nan {
             FpCategory::Nan
@@ -126,11 +127,11 @@ impl<F: Format> MicroFloat<F> {
         }
     }
 
-    pub fn copysign(self, sign: Self) -> Self {
+    pub const fn copysign(self, sign: Self) -> Self {
         if matches!(F::NAN, NanEncoding::Single(_)) && self.is_nan() {
             return self;
         }
-        if F::SIGN == SignMode::Unsigned {
+        if matches!(F::SIGN, SignMode::Unsigned) {
             self
         } else if sign.is_sign_negative() {
             Self::from_bits(abs_bits::<F>(self.bits) | F::SIGN_BIT)
@@ -139,8 +140,8 @@ impl<F: Format> MicroFloat<F> {
         }
     }
 
-    pub fn signum(self) -> Self {
-        if self.is_nan() || self.classify() == FpCategory::Zero {
+    pub const fn signum(self) -> Self {
+        if self.is_nan() || matches!(self.classify(), FpCategory::Zero) {
             self
         } else if self.is_sign_negative() {
             Self::NEG_ONE
@@ -149,7 +150,7 @@ impl<F: Format> MicroFloat<F> {
         }
     }
 
-    pub fn abs(self) -> Self {
+    pub const fn abs(self) -> Self {
         if matches!(F::NAN, NanEncoding::Single(_)) && self.is_nan() {
             return self;
         }

tests/const_methods.rs

@@ -0,0 +1,54 @@
+use microfloat::{
+    f4e2m1fn, f6e2m3fn, f6e3m2fn, f8e3m4, f8e4m3, f8e4m3b11fnuz, f8e4m3fn, f8e4m3fnuz, f8e5m2,
+    f8e5m2fnuz, f8e8m0fnu,
+};
+
+macro_rules! assert_const_methods_compile {
+    ($($type:ty),* $(,)?) => {
+        $(
+            const _: () = {
+                let value = <$type>::from_bits(0x01);
+                let sign = <$type>::NEG_ONE;
+                let bits = value.to_bits();
+                let _ = <$type>::from_le_bytes([bits]);
+                let _ = <$type>::from_be_bytes([bits]);
+                let _ = <$type>::from_ne_bytes([bits]);
+                let _ = value.to_le_bytes();
+                let _ = value.to_be_bytes();
+                let _ = value.to_ne_bytes();
+                let _ = <$type>::has_inf();
+                let _ = <$type>::has_nan();
+                let _ = <$type>::is_finite_only();
+                let _ = value.is_nan();
+                let _ = value.is_infinite();
+                let _ = value.is_finite();
+                let _ = value.is_normal();
+                let _ = value.classify();
+                let _ = value.is_sign_positive();
+                let _ = value.is_sign_negative();
+                let _ = value.copysign(sign);
+                let _ = value.signum();
+                let _ = value.abs();
+                let _ = value.next_up();
+                let _ = value.next_down();
+            };
+        )*
+    };
+}
+
+assert_const_methods_compile!(
+    f8e3m4,
+    f8e4m3,
+    f8e4m3b11fnuz,
+    f8e4m3fn,
+    f8e4m3fnuz,
+    f8e5m2,
+    f8e5m2fnuz,
+    f8e8m0fnu,
+    f4e2m1fn,
+    f6e2m3fn,
+    f6e3m2fn,
+);
+
+#[test]
+fn const_methods_compile() {}