# Decimal

Decimal numbers with variable precision https://github.com/PaulJohnson/Haskell-Decimal

Version on this page: | 0.4.2 |

LTS Haskell 9.9: | 0.4.2 |

Stackage Nightly 2017-10-13: | 0.4.2 |

Latest on Hackage: | 0.4.2 |

BSD3 licensed by

**Paul Johnson**Maintained by

**paul@cogito.org.uk**#### Module documentation for 0.4.2

- Data

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

-------------

Improved "Read" instance. Now handles "1.2e3" and "reads" only returns a

single parse.

Corrected documentation.

Added "Enum" instance.

"decimalConvert" now returns a Maybe value. The old version has been renamed

to "unsafeDecimalConvert.

Version 0.4.2

-------------

Removed spurious "Integer" type context.

==================================

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

-------------

Improved "Read" instance. Now handles "1.2e3" and "reads" only returns a

single parse.

Corrected documentation.

Added "Enum" instance.

"decimalConvert" now returns a Maybe value. The old version has been renamed

to "unsafeDecimalConvert.

Version 0.4.2

-------------

Removed spurious "Integer" type context.

Used by 22 packages:

algebra-sql, buchhaltung, cassandra-cql, cql, DSH, dsh-sql, fadno, fadno-xml, hax, hbcd, hdbi, hdbi-tests, hledger-api, hledger-interest, hledger-irr, hledger-lib, oanda-rest-api, paypal-rest-client, pipes-misc, sdr, tsparse, yxdb-utils

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