quantities 0.10.0

Unit-safe computations with quantities.
Documentation 
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// ---------------------------------------------------------------------------
// Copyright:   (c) 2022 ff. Michael Amrhein (michael@adrhinum.de)
// License:     This program is part of a larger application. For license
//              details please read the file LICENSE.TXT provided together
//              with the application.
// ---------------------------------------------------------------------------
// $Source: src/amnt_dec.rs $
// $Revision: 2022-04-17T15:02:37+02:00 $

pub use fpdec::{Dec, Decimal};

/// Type used for the numerical part of a Quantity.
///
/// When feature `fpdec` is off (= default), AmountT is defined as `f64` on a
/// 64-bit system or as `f32` on a 32-bit system.
///
/// When feature fpdec is activated, AmountT is defined as `Decimal`
/// (imported from crate `fpdec`).
///
/// The macro `Amnt!` can be used to convert float literals correctly to
/// `AmountT` depending on the configuration.
pub type AmountT = Decimal;

/// AmountT constant equal 0
pub const AMNT_ZERO: AmountT = Decimal::ZERO;

/// AmountT constant equal 1
pub const AMNT_ONE: AmountT = Decimal::ONE;

#[allow(non_snake_case)]
#[macro_export]
/// Converts a numeric literal to an `AmountT`.
macro_rules! Amnt {
    ($lit:literal) => {
        Dec!($lit)
    };
}

#[macro_export]
macro_rules! assert_almost_eq {
    ($x:expr, $y:expr) => {
        let t = if ($x).abs() >= ($y).abs() {
            ($x).abs() * Decimal::new_raw(1, 15)
        } else {
            ($y).abs() * Decimal::new_raw(1, 15)
        };
        assert!(($x - $y).abs() < t, "{} ≉ {}", ($x), ($y));
    };
}