Copyright	(c) Ashley Yakeley 2005 2006 2009
License	BSD-style (see the file libraries/base/LICENSE)
Maintainer	Ashley Yakeley <ashley@semantic.org>
Stability	experimental
Portability	portable
Safe Haskell	Trustworthy
Language	Haskell2010

Data.Fixed

Description

This module defines a "Fixed" type for fixed-precision arithmetic. The parameter to Fixed is any type that's an instance of HasResolution. HasResolution has a single method that gives the resolution of the Fixed type.

This module also contains generalisations of div, mod, and divMod to work with any Real instance.

Synopsis

div' :: (Real a, Integral b) => a -> a -> b
mod' :: Real a => a -> a -> a
divMod' :: (Real a, Integral b) => a -> a -> (b, a)
newtype Fixed (a :: k) = MkFixed Integer
class HasResolution (a :: k) where
- resolution :: p a -> Integer
showFixed :: HasResolution a => Bool -> Fixed a -> String
data E0
type Uni = Fixed E0
data E1
type Deci = Fixed E1
data E2
type Centi = Fixed E2
data E3
type Milli = Fixed E3
data E6
type Micro = Fixed E6
data E9
type Nano = Fixed E9
data E12
type Pico = Fixed E12

Documentation

div' :: (Real a, Integral b) => a -> a -> b Source #

Generalisation of div to any instance of Real

mod' :: Real a => a -> a -> a Source #

Generalisation of mod to any instance of Real

divMod' :: (Real a, Integral b) => a -> a -> (b, a) Source #

Generalisation of divMod to any instance of Real

newtype Fixed (a :: k) Source #

The type parameter should be an instance of HasResolution.

Constructors

MkFixed Integer

Instances

Instances details

(Typeable k, Typeable a) => Data (Fixed a) #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Fixed a -> c (Fixed a) Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Fixed a) Source # toConstr :: Fixed a -> Constr Source # dataTypeOf :: Fixed a -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Fixed a)) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Fixed a)) Source # gmapT :: (forall b. Data b => b -> b) -> Fixed a -> Fixed a Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Fixed a -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Fixed a -> r Source # gmapQ :: (forall d. Data d => d -> u) -> Fixed a -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> Fixed a -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Fixed a -> m (Fixed a) Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Fixed a -> m (Fixed a) Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Fixed a -> m (Fixed a) Source #
Enum (Fixed a) #	Recall that, for numeric types, `succ` and `pred` typically add and subtract `1`, respectively. This is not true in the case of `Fixed`, whose successor and predecessor functions intuitively return the "next" and "previous" values in the enumeration. The results of these functions thus depend on the resolution of the `Fixed` value. For example, when enumerating values of resolution `10^-3` of `type Milli = Fixed E3`, succ (0.000 :: Milli) == 1.001 and likewise pred (0.000 :: Milli) == -0.001 In other words, `succ` and `pred` increment and decrement a fixed-precision value by the least amount such that the value's resolution is unchanged. For example, `10^-12` is the smallest (positive) amount that can be added to a value of `type Pico = Fixed E12` without changing its resolution, and so succ (0.000000000000 :: Pico) == 0.000000000001 and similarly pred (0.000000000000 :: Pico) == -0.000000000001 This is worth bearing in mind when defining `Fixed` arithmetic sequences. In particular, you may be forgiven for thinking the sequence [1..10] :: [Pico] evaluates to `[1, 2, 3, 4, 5, 6, 7, 8, 9, 10] :: [Pico]`. However, this is not true. On the contrary, similarly to the above implementations of `succ` and `pred`, `enumFromTo :: Pico -> Pico -> [Pico]` has a "step size" of `10^-12`. Hence, the list `[1..10] :: [Pico]` has the form [1.000000000000, 1.00000000001, 1.00000000002, ..., 10.000000000000] and contains `9 * 10^12 + 1` values. Since: base-2.1
Instance details Defined in Data.Fixed Methods succ :: Fixed a -> Fixed a Source # pred :: Fixed a -> Fixed a Source # toEnum :: Int -> Fixed a Source # fromEnum :: Fixed a -> Int Source # enumFrom :: Fixed a -> [Fixed a] Source # enumFromThen :: Fixed a -> Fixed a -> [Fixed a] Source # enumFromTo :: Fixed a -> Fixed a -> [Fixed a] Source # enumFromThenTo :: Fixed a -> Fixed a -> Fixed a -> [Fixed a] Source #
HasResolution a => Num (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods (+) :: Fixed a -> Fixed a -> Fixed a Source # (-) :: Fixed a -> Fixed a -> Fixed a Source # (*) :: Fixed a -> Fixed a -> Fixed a Source # negate :: Fixed a -> Fixed a Source # abs :: Fixed a -> Fixed a Source # signum :: Fixed a -> Fixed a Source # fromInteger :: Integer -> Fixed a Source #
HasResolution a => Read (Fixed a) #	Since: base-4.3.0.0
Instance details Defined in Data.Fixed Methods readsPrec :: Int -> ReadS (Fixed a) Source # readList :: ReadS [Fixed a] Source # readPrec :: ReadPrec (Fixed a) Source # readListPrec :: ReadPrec [Fixed a] Source #
HasResolution a => Fractional (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods (/) :: Fixed a -> Fixed a -> Fixed a Source # recip :: Fixed a -> Fixed a Source # fromRational :: Rational -> Fixed a Source #
HasResolution a => Real (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods toRational :: Fixed a -> Rational Source #
HasResolution a => RealFrac (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods properFraction :: Integral b => Fixed a -> (b, Fixed a) Source # truncate :: Integral b => Fixed a -> b Source # round :: Integral b => Fixed a -> b Source # ceiling :: Integral b => Fixed a -> b Source # floor :: Integral b => Fixed a -> b Source #
HasResolution a => Show (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods showsPrec :: Int -> Fixed a -> ShowS Source # show :: Fixed a -> String Source # showList :: [Fixed a] -> ShowS Source #
Eq (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods (==) :: Fixed a -> Fixed a -> Bool Source # (/=) :: Fixed a -> Fixed a -> Bool Source #
Ord (Fixed a) #	Since: base-2.1
Instance details Defined in Data.Fixed Methods compare :: Fixed a -> Fixed a -> Ordering Source # (<) :: Fixed a -> Fixed a -> Bool Source # (<=) :: Fixed a -> Fixed a -> Bool Source # (>) :: Fixed a -> Fixed a -> Bool Source # (>=) :: Fixed a -> Fixed a -> Bool Source # max :: Fixed a -> Fixed a -> Fixed a Source # min :: Fixed a -> Fixed a -> Fixed a Source #

class HasResolution (a :: k) where Source #

Methods

resolution :: p a -> Integer Source #

Instances

Instances details

KnownNat n => HasResolution (n :: Nat) #	For example, `Fixed 1000` will give you a `Fixed` with a resolution of 1000.
Instance details Defined in Data.Fixed Methods resolution :: p n -> Integer Source #
HasResolution E0 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E0 -> Integer Source #
HasResolution E1 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E1 -> Integer Source #
HasResolution E12 #	Since: base-2.1
Instance details Defined in Data.Fixed Methods resolution :: p E12 -> Integer Source #
HasResolution E2 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E2 -> Integer Source #
HasResolution E3 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E3 -> Integer Source #
HasResolution E6 #	Since: base-2.1
Instance details Defined in Data.Fixed Methods resolution :: p E6 -> Integer Source #
HasResolution E9 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E9 -> Integer Source #

showFixed :: HasResolution a => Bool -> Fixed a -> String Source #

First arg is whether to chop off trailing zeros

data E0 Source #

Instances

Instances details

HasResolution E0 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E0 -> Integer Source #

type Uni = Fixed E0 Source #

resolution of 1, this works the same as Integer

data E1 Source #

Instances

Instances details

HasResolution E1 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E1 -> Integer Source #

type Deci = Fixed E1 Source #

resolution of 10^-1 = .1

data E2 Source #

Instances

Instances details

HasResolution E2 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E2 -> Integer Source #

type Centi = Fixed E2 Source #

resolution of 10^-2 = .01, useful for many monetary currencies

data E3 Source #

Instances

Instances details

HasResolution E3 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E3 -> Integer Source #

type Milli = Fixed E3 Source #

resolution of 10^-3 = .001

data E6 Source #

Instances

Instances details

HasResolution E6 #	Since: base-2.1
Instance details Defined in Data.Fixed Methods resolution :: p E6 -> Integer Source #

type Micro = Fixed E6 Source #

resolution of 10^-6 = .000001

data E9 Source #

Instances

Instances details

HasResolution E9 #	Since: base-4.1.0.0
Instance details Defined in Data.Fixed Methods resolution :: p E9 -> Integer Source #

type Nano = Fixed E9 Source #

resolution of 10^-9 = .000000001

data E12 Source #

Instances

Instances details

HasResolution E12 #	Since: base-2.1
Instance details Defined in Data.Fixed Methods resolution :: p E12 -> Integer Source #

type Pico = Fixed E12 Source #

resolution of 10^-12 = .000000000001