HMRC Currency Conversion Library

This Rust library provides a simple and efficient way to convert various currencies to GBP using HMRC's monthly exchange rates. It is designed to be easy to use, with a straightforward API that handles the complexities of parsing and looking up exchange rates for you.

Getting Started

To use this library in your project, simply add the following to your Cargo.toml file:

[dependencies]
hmrc-rates = "0.1.0"

Usage

use hmrc_rates::{HMRCMonthlyRatesConverter, ConversionError};
use chrono::NaiveDate;
use rust_decimal_macros::dec;

fn main() -> Result<(), ConversionError> {
    // Create a new converter with the default rates.
    let converter = HMRCMonthlyRatesConverter::with_default_rates()?;

    let trade_date = NaiveDate::from_ymd_opt(2025, 8, 15).unwrap();
    let amount = dec!(100.00);

    // Perform the conversion.
    let gbp_value = converter.convert(amount, "USD", trade_date)?;

    println!("{} USD on {} was {}", amount, trade_date, gbp_value);
    // Expected output: 100.00 USD on 2025-08-15 was £73.85

    Ok(())
}

Contributing

Contributions are welcome! If you find any issues or have suggestions for improvements, please open an issue or submit a pull request.