# Decimal: Decimal numbers with variable precision

[ bsd3, library, math ] [ Propose Tags ]

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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Versions [RSS] 0.1.0, 0.2.0, 0.2.1, 0.2.2, 0.2.3, 0.3.1, 0.4.1, 0.4.2, 0.5.1, 0.5.2 base (>=4 && <4.15), deepseq [details] BSD-3-Clause Paul Johnson, 2013 Paul Johnson paul@cogito.org.uk Revision 1 made by Bodigrim at 2022-07-13T21:28:49Z Math https://github.com/PaulJohnson/Haskell-Decimal by PaulJohnson at 2014-09-28T09:42:11Z Arch:0.5.2, Debian:0.5.1, Fedora:0.5.2, LTSHaskell:0.5.2, NixOS:0.5.2, Stackage:0.5.2, openSUSE:0.5.2 31 direct, 17 indirect [details] 22357 total (91 in the last 30 days) (no votes yet) [estimated by Bayesian average] λ λ λ Docs uploaded by userBuild status unknown

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Variable Precision Decimal Numbers
==================================

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.
Binary operators return a result with the precision of the most
precise argument, so 2.3 + 5.678 = 7.978.

If you need fixed precision decimal arithmetic where the precision is
known at compile time then Data.Number.Fixed from Lennart Augustsson's
"numbers" package is more likely to be what you want.

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

Version 0.2.1
-------------

Fixed "base" dependency.
Put test suite under "cabal test"

Version 0.2.2
-------------

Minor fixes to allow compilation under other versions of GHC.

Version 0.2.3
-------------

Added instance of NFData from Control.DeepSeq, and hence a dependency
on the deepseq package, thanks to Jeff Shaw (shawjef3 at msu.edu).

Version 0.3.1
-------------

Added Typeable, Fractional and RealFrac instances.
Multiplication now returns an exact result, increasing precision if necessary.

These changes alter the API. Hence the increment to the major version number.

Thanks to Alexey Uimanov (s9gf4ult at gmail.com).

Version 0.4.1
-------------