decimal-scaled 0.2.2

Const-generic base-10 fixed-point decimals (D9/D18/D38/D76/D153/D307) with integer-only transcendentals correctly rounded to within 0.5 ULP — exact at the type's last representable place. Deterministic across every platform; no_std-friendly.
Documentation 
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//! `PartialEq` impls between every decimal width and primitive numeric
//! types. Wires the macro emissions in `src/macros/equalities.rs` to
//! each concrete width.
//!
//! # Semantics
//!
//! - **Integers** (`i8`-`i128`, `u8`-`u128`, `isize`, `usize`): exact
//! mathematical equality. `d == n` holds iff `d.to_bits() == n * 10^SCALE`,
//! i.e. `d` represents the integer `n` with no fractional part. The
//! comparison is computed without overflow by splitting `d.to_bits()` into
//! quotient and remainder modulo `10^SCALE`; the value is equal to `n` iff
//! the remainder is zero and the quotient equals `n`.
//!
//! Examples:
//! - `D38s12::from_int(5) == 5_i32` -> `true`
//! - `D38s12::from_bits(5_500_000_000_000) == 5_i32` -> `false` (5.5 != 5)
//! - `D38s12::from_bits(-1) == 0_u32` -> `false` (negative value)
//!
//! - **Floats** (`f32`, `f64`): equality holds iff `f` is finite and converts
//! to and from `D38` losslessly relative to the f64 representation. NaN and
//! ±inf always compare unequal. A `D38` value larger than `2^53` cannot
//! match any `f64` exactly and will compare unequal except when the float's
//! stored value happens to round-trip.
//!
//! Note that f64 cannot represent decimals like `1.1` exactly; the nearest
//! f64 to `1.1` is `1.1000000000000000888...`. The implementation treats
//! that nearest f64 as equal to `D38s12::from_bits(1_100_000_000_000)`
//! because the round-trip through `from_f64`/`to_f64` agrees.
//! Callers who need true rational equality should convert and compare
//! explicitly.
//!
//! Each impl provides both directions (`D38<S> == T` and `T == D38<S>`) so
//! comparisons are symmetric at the call site.

use crate::core_type::{D38, D9, D18};

// Cross-equality with primitive integer types is emitted by the
// `decl_eq_all_integers!` macro family in `src/macros/equalities.rs`.
// The same surface is generated for every decimal width.
crate::macros::equalities::decl_eq_all_integers!(D38);
crate::macros::equalities::decl_eq_all_integers!(D18);
crate::macros::equalities::decl_eq_all_integers!(D9);

#[cfg(any(feature = "d76", feature = "wide"))]
use crate::core_type::D76;
#[cfg(any(feature = "d153", feature = "wide"))]
use crate::core_type::D153;
#[cfg(any(feature = "d307", feature = "wide"))]
use crate::core_type::D307;

#[cfg(any(feature = "d76", feature = "wide"))]
crate::macros::equalities::decl_eq_all_integers!(wide D76);
#[cfg(any(feature = "d153", feature = "wide"))]
crate::macros::equalities::decl_eq_all_integers!(wide D153);
#[cfg(any(feature = "d307", feature = "wide"))]
crate::macros::equalities::decl_eq_all_integers!(wide D307);

// Float equality requires the f64 bridge (`from_f64` / `to_f64`),
// which is gated on `std`. Float impls are emitted for every width
// below.
#[cfg(feature = "std")]
crate::macros::equalities::decl_eq_float!(D38, f32);
#[cfg(feature = "std")]
crate::macros::equalities::decl_eq_float!(D38, f64);
#[cfg(feature = "std")]
crate::macros::equalities::decl_eq_float!(D18, f32);
#[cfg(feature = "std")]
crate::macros::equalities::decl_eq_float!(D18, f64);
#[cfg(feature = "std")]
crate::macros::equalities::decl_eq_float!(D9, f32);
#[cfg(feature = "std")]
crate::macros::equalities::decl_eq_float!(D9, f64);

// Wide tiers share the same float-bridge surface, so the same macro
// applies unchanged.
#[cfg(all(feature = "std", any(feature = "d76", feature = "wide")))]
crate::macros::equalities::decl_eq_float!(D76, f32);
#[cfg(all(feature = "std", any(feature = "d76", feature = "wide")))]
crate::macros::equalities::decl_eq_float!(D76, f64);
#[cfg(all(feature = "std", any(feature = "d153", feature = "wide")))]
crate::macros::equalities::decl_eq_float!(D153, f32);
#[cfg(all(feature = "std", any(feature = "d153", feature = "wide")))]
crate::macros::equalities::decl_eq_float!(D153, f64);
#[cfg(all(feature = "std", any(feature = "d307", feature = "wide")))]
crate::macros::equalities::decl_eq_float!(D307, f32);
#[cfg(all(feature = "std", any(feature = "d307", feature = "wide")))]
crate::macros::equalities::decl_eq_float!(D307, f64);