Module collateral 

The discount-curve key — a collateral specification (pure reference data).

CollateralSpec names which discount curve a cashflow is collateralised against. It is a pure value type over Currency with no state and no market dependency, so it lives in statics — letting both the curve-recipe registry (which keys recipes by it) and the MarketContext discount registry (which resolves curves by it) share one key without an upward layer edge.

One key, not two

There were two types spelled CollateralSpec: this one, and a {cashflow_ccy, collateral_ccy} pair of currency codes that only the recipe registry used. They were not interchangeable, so a recipe could not be looked up by the key a trade declares — which was the whole point of keying recipes by a collateral spec. The pair is gone and this is the survivor, because it is the one that can represent what callers actually pin curves under: FromStr here is total, and keys like CSA-ACME-2026 or TRY-implied decompose into no currency pair at all.

The two-code question a recipe asks is therefore answered fallibly, by parts. A key that names no currency pair has no recipe, which is an answer rather than a lost case.

Not to be confused with the xccy template CsaSpec, which is the CSA definition (collateral currency + its overnight index); CollateralSpec is the discount key.

Structs

NotACollateralCurrency

A collateral argument that is not a currency code: collateral is always the currency posted, never an index or a discount key.

Enums

CollateralSpec

Which discount curve a product is collateralised against.

Constants

CSA_INFIX 🔒

The infix separating the cashflow currency from its collateral currency in a named cross-collateral key: "EUR-CSA-USD" is EUR flows under a USD CSA.

Functions

collateral_currency

The currency a collateral argument names.