raed667 / dinero Goto Github PK

Explore the idea of transforming Currency to a trait.

Current implementation

Today the Dinero struct looks like this:

#[derive(Debug, Clone, Copy, Eq)]
pub struct Dinero {
    pub amount: i128,
    pub currency: Currency, // <-- 
    pub scale: u32,
}

Goals

When doing operations on Dinero we often check if they have the same currency at run-time.

Example:

let a = Dinero::new(1, EUR, None);
let b = Dinero::new(2, USD, None);

let z = add(x,y); // <-- This will return an `UnequalCurrencyError`

Possible implementation

Using Bounds this can be done at compile time.

pub trait Currency {
    const CODE: CountryCode;
    const BASE: u32;
    const EXPONENT: u32;
}

Then maybe the Dinero struct can look something like this?

#[derive(Debug, Clone, Copy)]
pub struct Dinero<Currency> { // <-- Not sure how to reference the currency here?
    pub amount: i128,
    pub scale: u32,
}

// A constructor would look like this?
impl Dinero<dyn Currency> {
    pub fn new(amount: i128, scale: Option<u32>) -> Dinero<dyn Currency> {
        Dinero {
            scale: scale.unwrap_or_else(|| self::Currency::EXPONENT.to_owned()),
            amount,
        }
    }
}


let d = Dinero::<USD>::new(42, Some(2));

I'm still not sure how to make this work synthetically. So any help is more than welcome!

Implement the function convert.

https://v2.dinerojs.com/docs

Release new versions using Github Actions.

List of things to do before v1 release:

• Determine finite list of features to port from https://v2.dinerojs.com/docs
• Write all selected functions
• Test all selected functions
• Refactor code outside of core/src/lib.rs to make it easier to maintain
• Add CI (lint, build, coverage, etc...)
• Write docs for docs.rs
• Make a doc landing page + ReadMe with more user-friendly guides
• ???

List of selected functions

• allocate
• trim_scale
• transform_scale
• normalize_scale
• add
• subtract
• multiply
• is_zero
• is_negative
• is_positive
• have_same_amount
• have_same_currency
• ???

Post release to do:

• Setup auto-release and contribution guides
• Setup contrib list
• Setup issue templates
• ???

What would be the best type to use?

Should we use a BigInt sort of library instead?

This would be more useful than the docs.rs generated documentation.