70ecd6caa0
Transaction Science open standards monorepo. Each subdirectory is a self-contained reference protocol with its own README and licence. - openpay/ Apache-2.0 payment-acceptance stack (Rust, 26 crates) - smart-byte/ CC-BY-4.0 content-addressed value carrier (spec) - eoc/ CC-BY-4.0 energy-optimised compute (spec) The wire format and the right to fork are public. The optional hosted services are the offer; the protocols are not.
50 lines
2 KiB
Rust
50 lines
2 KiB
Rust
//! # `op-fx` — Foreign-exchange primitives for `OpenPay`
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//!
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//! Integer-exact currency conversion with deterministic rounding,
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//! pluggable quote sources, and TTL-based caching. The reference
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//! stack ships no network clients — operators wire their preferred
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//! FX feed (Wise, Open Exchange Rates, internal mid-market, bank
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//! API) behind the [`QuoteProvider`] trait.
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//!
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//! ## Why integer math
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//!
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//! FX is one of the most-cited examples of "don't use floats for
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//! money." A 0.0001 rounding error on `$10M` is $1000 the bank
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//! cares about. We represent rates as
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//! **parts per million** (`u64`): `1.000000 = 1_000_000`. Six
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//! decimal places of precision is the FX industry standard for
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//! spot rates; carrying more is meaningless given bid/ask spreads.
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//!
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//! Conversion math: `target_minor = source_minor * rate_ppm /
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//! 1_000_000`, with a caller-chosen [`RoundingMode`] for the
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//! remainder. No floats anywhere in the conversion pipeline.
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//!
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//! ## What the crate does NOT do
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//!
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//! - **No HTTP client.** [`QuoteProvider`] is the seam; the only
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//! concrete impls shipped are [`StaticQuoteProvider`] (fixed
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//! rate table, for tests + operator-locked rates) and
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//! [`CachedQuoteProvider`] (TTL wrapper).
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//! - **No spread / fee modeling.** Operators apply their own
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//! spread by adjusting the rate they hand to the provider.
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//! - **No triangulation.** A USD/JPY quote is direct; we don't
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//! auto-route via USD/EUR + EUR/JPY. Operators who need cross-
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//! rates assemble them themselves.
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//! - **No hedging engine.** Quote validity windows are reported,
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//! not enforced — callers check `valid_until_unix_secs`.
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#![forbid(unsafe_code)]
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#![warn(missing_docs)]
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#![warn(clippy::pedantic)]
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#![allow(clippy::module_name_repetitions)]
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#![allow(clippy::missing_errors_doc)]
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pub mod convert;
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pub mod error;
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pub mod provider;
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pub mod quote;
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pub use convert::{RoundingMode, convert};
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pub use error::{Error, Result};
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pub use provider::{CachedQuoteProvider, QuoteProvider, StaticQuoteProvider};
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pub use quote::Quote;
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