add IS_SIGNED associated constant

README.md

@@ -86,9 +86,10 @@ The conversions supported cover the following cases.
       * [`next_power_of_two`][f-npot-1-7],
         [`checked_next_power_of_two`][f-cnpot-1-7],
         [`wrapping_next_power_of_two`][f-wnpot-1-7]
-  * The following methods were added to all fixed-point numbers, to
-    the [`Fixed`][tf-1-7] trait, and to the [`Wrapping`][w-1-7] and
-    [`Unwrapped`][u-1-7] wrappers:
+  * The following constant and methods were added to all fixed-point
+    numbers, to the [`Fixed`][tf-1-7] trait, and to the
+    [`Wrapping`][w-1-7] and [`Unwrapped`][u-1-7] wrappers:
+      * [`IS_SIGNED`][f-is-1-7]
       * [`from_be`][f-fb-1-7], [`from_le`][f-fl-1-7]
       * [`to_be`][f-tb-1-7], [`to_le`][f-tl-1-7]
       * [`swap_bytes`][f-sb-1-7]
@@ -110,7 +111,7 @@ The conversions supported cover the following cases.
     signed numbers.
   * The following constants, which are available in other programming
     language standard libraries, were added to the [`consts`][c-1-7]
-    module and as associated constants for fixed-point types:
+    module and as associated constants to fixed-point types:
       * [`SQRT_PI`][c-rp-1-7] (Go), [`FRAC_1_SQRT_PI`][c-1rp-1-7] (C++)
       * [`SQRT_3`][c-r3-1-7] (C++), [`FRAC_1_SQRT_3`][c-1r3-1-7] (C++)
       * [`SQRT_E`][c-re-1-7] (Go)
@@ -148,6 +149,7 @@ The conversions supported cover the following cases.
 [f-fl-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.from_le
 [f-flb-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.from_le_bytes
 [f-fnb-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.from_ne_bytes
+[f-is-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#associatedconstant.IS_SIGNED
 [f-m-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.midpoint
 [f-npot-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedU32.html#method.next_power_of_two
 [f-rb-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.reverse_bits

RELEASES.md

@@ -13,9 +13,10 @@ Version 1.7.0 (unreleased)
       * [`next_power_of_two`][f-npot-1-7],
         [`checked_next_power_of_two`][f-cnpot-1-7],
         [`wrapping_next_power_of_two`][f-wnpot-1-7]
-  * The following methods were added to all fixed-point numbers, to
-    the [`Fixed`][tf-1-7] trait, and to the [`Wrapping`][w-1-7] and
-    [`Unwrapped`][u-1-7] wrappers:
+  * The following constant and methods were added to all fixed-point
+    numbers, to the [`Fixed`][tf-1-7] trait, and to the
+    [`Wrapping`][w-1-7] and [`Unwrapped`][u-1-7] wrappers:
+      * [`IS_SIGNED`][f-is-1-7]
       * [`from_be`][f-fb-1-7], [`from_le`][f-fl-1-7]
       * [`to_be`][f-tb-1-7], [`to_le`][f-tl-1-7]
       * [`swap_bytes`][f-sb-1-7]
@@ -37,7 +38,7 @@ Version 1.7.0 (unreleased)
     signed numbers.
   * The following constants, which are available in other programming
     language standard libraries, were added to the [`consts`][c-1-7]
-    module and as associated constants for fixed-point types:
+    module and as associated constants to fixed-point types:
       * [`SQRT_PI`][c-rp-1-7] (Go), [`FRAC_1_SQRT_PI`][c-1rp-1-7] (C++)
       * [`SQRT_3`][c-r3-1-7] (C++), [`FRAC_1_SQRT_3`][c-1r3-1-7] (C++)
       * [`SQRT_E`][c-re-1-7] (Go)
@@ -73,6 +74,7 @@ Version 1.7.0 (unreleased)
 [f-fl-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.from_le
 [f-flb-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.from_le_bytes
 [f-fnb-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.from_ne_bytes
+[f-is-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#associatedconstant.IS_SIGNED
 [f-m-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.midpoint
 [f-npot-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedU32.html#method.next_power_of_two
 [f-rb-1-7]: https://tspiteri.gitlab.io/fixed/dev/fixed/struct.FixedI32.html#method.reverse_bits
@@ -279,7 +281,7 @@ Version 0.5.7 (2020-05-11)
     to the `FixedUnsigned` trait:
       * `wrapping_next_power_of_two`
   * The `PHI` and `FRAC_1_PHI` constants were added to the `consts`
-    module and as associated constants for fixed-point types.
+    module and as associated constants to fixed-point types.
 
 Version 0.5.6 (2020-05-01)
 ==========================

src/macros_no_frac.rs

@@ -51,6 +51,26 @@ assert_eq!(Fix::MAX, Fix::from_bits(", $s_inner, "::MAX));
                 pub const MAX: $Fixed<Frac> = Self::from_bits(<$Inner>::MAX);
             }
 
+            comment! {
+                if_signed_unsigned!($Signedness, "[`true`]", "[`false`]"),
+                "[`bool`] because the [`", $s_fixed, "`] type is ",
+                if_signed_unsigned!($Signedness, "signed", "unsigned"),
+                ".
+
+# Examples
+
+```rust
+use fixed::{types::extra::U4, ", $s_fixed, "};
+type Fix = ", $s_fixed, "<U4>;
+assert!(", if_signed_unsigned!($Signedness, "", "!"), "Fix::IS_SIGNED);
+```
+
+[`", $s_fixed, "`]: #
+[`bool`]: https://doc.rust-lang.org/nightly/std/primitive.bool.html
+";
+                pub const IS_SIGNED: bool = if_signed_unsigned!($Signedness, true, false);
+            }
+
             comment! {
                 "Creates a fixed-point number that has a bitwise
 representation identical to the given integer.

src/traits.rs

@@ -358,6 +358,11 @@ where
     /// The largest value that can be represented.
     const MAX: Self;
 
+    /// [`true`][`bool`] if the type is signed.
+    ///
+    /// [`bool`]: https://doc.rust-lang.org/nightly/std/primitive.bool.html
+    const IS_SIGNED: bool;
+
     /// The number of integer bits.
     const INT_NBITS: u32;
 
@@ -2382,6 +2387,7 @@ macro_rules! impl_fixed {
             type Frac = Frac;
             const MIN: Self = Self::MIN;
             const MAX: Self = Self::MAX;
+            const IS_SIGNED: bool = Self::IS_SIGNED;
             const INT_NBITS: u32 = Self::INT_NBITS;
             const FRAC_NBITS: u32 = Self::FRAC_NBITS;
             trait_delegate! { fn from_bits(bits: Self::Bits) -> Self }

src/unwrapped.rs

@@ -72,6 +72,22 @@ impl<F: Fixed> Unwrapped<F> {
     /// ```
     pub const MAX: Unwrapped<F> = Unwrapped(F::MAX);
 
+    /// [`true`][`bool`] if the type is signed.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use fixed::{
+    ///     types::{I16F16, U16F16},
+    ///     Unwrapped,
+    /// };
+    /// assert!(Unwrapped::<I16F16>::IS_SIGNED);
+    /// assert!(!Unwrapped::<U16F16>::IS_SIGNED);
+    /// ```
+    ///
+    /// [`bool`]: https://doc.rust-lang.org/nightly/std/primitive.bool.html
+    pub const IS_SIGNED: bool = F::IS_SIGNED;
+
     /// The number of integer bits.
     ///
     /// # Examples

src/wrapping.rs

@@ -69,6 +69,22 @@ impl<F: Fixed> Wrapping<F> {
     /// ```
     pub const MAX: Wrapping<F> = Wrapping(F::MAX);
 
+    /// [`true`][`bool`] if the type is signed.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use fixed::{
+    ///     types::{I16F16, U16F16},
+    ///     Wrapping,
+    /// };
+    /// assert!(Wrapping::<I16F16>::IS_SIGNED);
+    /// assert!(!Wrapping::<U16F16>::IS_SIGNED);
+    /// ```
+    ///
+    /// [`bool`]: https://doc.rust-lang.org/nightly/std/primitive.bool.html
+    pub const IS_SIGNED: bool = F::IS_SIGNED;
+
     /// The number of integer bits.
     ///
     /// # Examples