The Decimal package

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A decimal number has an integer mantissa and a negative exponent. The exponent can be interpreted as the number of decimal places in the value.

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Versions0.1.0, 0.2.0, 0.2.1, 0.2.2, 0.2.3, 0.3.1, 0.4.1, 0.4.2, 0.5.1, 0.5.1
Dependenciesbase (==4.*), deepseq [details]
CopyrightPaul Johnson, 2013, 2018.
AuthorPaul Johnson
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UploadedWed Jan 3 15:31:38 UTC 2018 by PaulJohnson




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Readme for Decimal-0.5.1

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Fixed-precision decimal numbers, where the precision is carried with the numbers at run-time.

The Decimal type is mainly intended for doing financial arithmetic where the number of decimal places may not be known at compile time (e.g. for a program that handles both Yen and Dollars) and the application must not drop pennies on the floor. For instance if you have to divide $10 between three people then one of them has to get $3.34.

The number of decimal places in a value is represented as a Word8, allowing for up to 255 decimal places. Functions preserve precision. Addition and subtraction operators return a result with the precision of the most precise argument, so 2.3 + 5.678 = 7.978. Multiplication and division use whatever precision is necessary up to 255 decimal places.

QuickCheck Specification

Data.Decimal includes a set of QuickCheck properties which act as both tests and a formal specification. To run the tests do:

cabal configure --enable-tests cabal build cabal test


stack test