safe-money

Type-safe and lossless encoding and manipulation of money, fiat currencies, crypto currencies and precious metals.

https://github.com/k0001/safe-money

Version on this page:0.9
LTS Haskell 22.14:0.9.1
Stackage Nightly 2023-12-26:0.9.1
Latest on Hackage:0.9.1

See all snapshots safe-money appears in

BSD-3-Clause licensed by Renzo Carbonara
Maintained by renλren!zone
This version can be pinned in stack with:safe-money-0.9@sha256:b34d829063582ff4eaa9deb75b940731a188cddc0529e9c654d4ff43a1a7b978,2475

Module documentation for 0.9

The Haskell safe-money library offers type-safe and lossless encoding and operations for monetary values in all world currencies, including fiat currencies, precious metals and crypto-currencies.

Useful instances for the many types defined by safe-money can be found in these other libraries:

Changes

Version 0.9

  • BREAKING CHANGE, POSSIBLY REQUIRING HUMAN INTERVENTION. Changed UnitScale "BSD" "cent" from (1, 1) to (100, 1), changed UnitScale "HTG" "centime" from (1, 1) to (100, 1), changed UnitScale "MDL" "leu" from (100, 1) to (1, 1), and changed UnitScale "SBD" "dollar" from (100, 1) to (1, 1). The scales in question were wrong before. If you relied on these specific scales, for example, for serializing and storing amounts in a database, you will need to rescale your amounts.

Version 0.8.1

  • Fix decimal rendering of some small cent values (e.g., 0.02). See issue #45.

  • Fixed xxxToDecimal docs. See issue #45.

  • Add someXxxToDecimal. See issue #44.

Version 0.8

  • COMPILER ASSISTED BREAKING CHANGE. Introduced DecimalConf, which all of the xxxToDecimal and xxxFromDecimal are now using. This concentrates all decimal rendering and parsing settings in a single place, and more importantly, it makes all of the xxxToDecimal return a Text value directly, rather than a Maybe Text. In turn, Separators has been introduced for configuring decimal and thousands separators. See issue #30.

  • COMPILER ASSISTED BREAKING CHANGE. The Scale type family was renamed to UnitScale.

  • COMPILER ASSISTED BREAKING CHANGE. Previous instances of the Scale type family where the currency and the unit were the same (e.g., Scale "USD" "USD"), intended to convey a canonical scale for the currency, are now written as CurrencyScale currency (e.g., CurrencyScale "USD").

  • COMPILER ASSISTED BREAKING CHANGE. A new datatype called Scale has been introduced. This datatype replaces term-level uses of Rational to convey the scale of a discrete monetary amount. The rationale for this, beyond improved type errors, is that checking for the scale’s validity can be done at a single place (namely, the new scaleFromRational), rather than everywhere a term-level scale was expected as input. See issue #43.

  • Added new approximation method HalfEven, also known as “Bankers rounding”. See issue #42.

  • New currencies: VES (see issue #33), UYW.

Version 0.7.1

  • Fixed compilation with GHC 8.6.

  • Fixed an issue when rendering decimal values smaller than the smallest possible fractional part. See issue #39.

Version 0.7

  • IMPORTANT. All of the changes in this release are fully backwards compatible. What happens in this release is that many instances previously exported by safe-money now live in different libraries so that downstream packages can avoid using Cabal flags to specify dependencies.

  • COMPILER ASSISTED BREAKING CHANGE. FromJSON and ToJSON (from aeson) instances are not exported from the safe-money library anymore. Instead, you are now expected to depend on the vetted safe-money-aeson library and import Money.Aeson to get the relevant instances. These instances are exactly the same ones previously exported by safe-money. As a consequence of this change, the aeson Cabal flag in safe-money and the optional dependency on aeson were removed, which simplifies downstream packaging.

  • COMPILER ASSISTED BREAKING CHANGE. Store (from store) instances are not exported from the safe-money library anymore. Instead, you are now expected to depend on the vetted safe-money-store library and import Money.Store to get the relevant instances. These instances are exactly the same ones previously exported by safe-money. As a consequence of this change, the store Cabal flag in safe-money and the optional dependency on serialise were removed, which simplifies downstream packaging.

  • COMPILER ASSISTED BREAKING CHANGE. Serialise (from serialise) instances are not exported from the safe-money library anymore. Instead, you are now expected to depend on the vetted safe-money-serialise library and import Money.Serialise to get the relevant instances. These instances are exactly the same ones previously exported by safe-money. As a consequence of this change, the serialise Cabal flag in safe-money and the optional dependency on serialise were removed, which simplifies downstream packaging.

  • COMPILER ASSISTED BREAKING CHANGE. Serialize (from cereal) instances are not exported from the safe-money library anymore. Instead, you are now expected to depend on the vetted safe-money-cereal library and import Money.Serialize to get the relevant instances. These instances are exactly the same ones previously exported by safe-money. As a consequence of this change, the cereal Cabal flag in safe-money and the optional dependency on cereal were removed, which simplifies downstream packaging.

  • COMPILER ASSISTED BREAKING CHANGE. FromXml and ToXml (from xmlbf) instances are not exported from the safe-money library anymore. Instead, you are now expected to depend on the vetted safe-money-xmlbf library and import Money.Aeson to get the relevant instances. These instances are exactly the same ones previously exported by safe-money. As a consequence of this change, the xmlbf Cabal flag in safe-money and the optional dependency on xmlbf were removed, which simplifies downstream packaging.

  • COMPILER ASSISTED BREAKING CHANGE. hashable and vector-space are now mandatory dependencies of safe-money. Hashable, VectorSpace and AdditiveGroup instances for the various safe-money datatypes are now exported from Money. The hashable and vector-space Cabal flags are now gone.

  • Arbitrary instances (from the QuickCheck packages) for the various safe-money datatypes are now exported from Money. QuickCheck is now a mandatory dependency of safe-money.

Version 0.6

  • COMPILER ASSISTED BREAKING CHANGE. denseToDecimal now takes a positive Rational rather than a Proxy scale.

  • COMPILER ASSISTED BREAKING CHANGE. denseFromDecimal and discreteFromDecimal now take a positive Rational scale, like their xxxToDecimal counterparts.

  • COMPILE ASSISTED BREAKING CHANGE. binary, deepseq and text are now mandatory dependencies since they are included with the standard GHC distribution. Thus, the tags for disabling them have been removed.

  • COMPILE ASSISTED BREAKING CHANGE. Text replaced the use of String in the public API. For example, denseCurrency now returns Text, instead of String. This change doesn’t break backwards compatibilility with binary serializations.

  • Introduced a new function discreteToDecimal.

  • Added tests to ensure backwards compatibility of serializations.

Version 0.5

  • COMPILER ASSISTED BREAKING CHANGE. The round, floor, ceiling and truncate functions were replaced by a single discreteFromDense function taking an argument of type Approximation (Round, Floor, Ceiling or Truncate) as an argument.

  • COMPILER ASSISTED BREAKING CHANGE. The fromDiscrete function was renamed to denseFromDiscrete.

  • COMPILER ASSISTED BREAKING CHANGE. The fromExchangeRate function was renamed to exchangeRateToRational.

  • COMPILER ASSISTED BREAKING CHANGE. The flipExchangeRate function was renamed to exchangeRateRecip.

  • COMPILER ASSISTED BREAKING CHANGE. The Dense is not an instance of Fractional anymore because recip and / could potentially crash.

  • Introduced new functions for rendering and parsing decimal reperesentations of monetary amounts: denseCurrency, discreteCurrency, denseFromDecimal, denseToDecimal, discreteFromDecimal, exchangeRateFromDecimal, exchangeRateToDecimal.

  • Introduced optional AdditiveGroup and VectorSpace group instances for Dense and Discrete. These type-classes come from the vector-space library and they can be enabled or disabled via the vector-space Cabal flag, which is enabled by default.

  • Introduced discrete constructor which behaves just like fromInteger.

  • Introduced the dense' constructor as an unsafe but convenient version of dense.

  • The ErrScaleNonCanonical type is now exported.

  • The Money.Internal module is now exposed, but hidden from the Haddock documentation.

  • New scale: "BTC" "millibitcoin".

  • Added many tests.

Version 0.4.1

  • ExchangeRate is now a Category.

Version 0.4

  • BREAKING CHANGE REQUIRING HUMAN INTERVENTION. The JSON serializations for all of Dense, SomeDense, Discrete, SomeDiscrete, ExchangeRate and SomeExchangeRate changed. The FromJSON instances are backwards compatible with the old serializations, but the ToJSON instances will only generate the new format, which is the same as the old format except the leading strings "Dense", "Discrete" and "ExchangeRate", respectively, are not present in the rendered JSON array anymore. So, if you were manually relying on the ToJSON instance, please update your code.

  • COMPILER ASSISTED BREAKING CHANGE. Changed the Rep suffix for a Some prefix Everywhere. For example, DenseRep was renamed to SomeDense.

  • COMPILER ASSISTED BREAKING CHANGE. Replaced the someDenseAmountNumerator and someDenseAmountDenominator Integers with a single someDenseAmount Rational number. Similarly for someDiscreteScale and someExchangeRateRate. The mkSomeDense, someDiscreteScale and mkSomeDense also take a Rational now.

  • COMPILER ASSISTED BREAKING CHANGE. The truncate, floor, celing and round functions now return just 0 as a reminder if there’s no significant reminder, instead of Nothing.

  • Added instances for serialise.

  • Added instances for xmlbf.

  • Fixed Show instances so that surrounding parentheses are included when necessary.

  • New currencies: Ripple, Litecoin, Ada, Monero.

Version 0.3

  • COMPILER ASSISTED BREAKING CHANGE. The Data.Money module was renamed to Money.

  • COMPILER ASSISTED BREAKING CHANGE. The Data.Money.Internal module is not exposed anymore. All of its contents are now exported from the Money module.

  • COMPILER ASSISTED BREAKING CHANGE. Renamed discreteRep to toDiscreteRep.

  • COMPILER ASSISTED BREAKING CHANGE. Renamed denseRep to toDenseRep.

  • COMPILER ASSISTED BREAKING CHANGE. Renamed exchangeRateRep to toExchangeRateRep.

  • COMPILER ASSISTED BREAKING CHANGE. Renamed Iceleandic currency "eyir" to "eyrir"

  • Remove upper bound constraints from all dependencies except base.

  • Made dependency on store optional for the test suite, so that it can run on GHCJS.

Version 0.2

  • Cabal flags are now manual (aeson, binary, bytes, cereal, deepseq, hashable).

  • Backwards compatibility with GHC 7.10.

  • Fix Store instances and test them.

Version 0.1

  • Initial release.