Safe Haskell	None
Language	Haskell2010

Haspara.Quantity

Contents

Data Definition
Smart Constructors
Utilities
Internal
Orphan instances

Description

This module provides definitions for modeling and working with quantities with fixed decimal points.

Synopsis

newtype Quantity (s :: Nat) = MkQuantity {
- unQuantity :: Decimal RoundHalfEven s Integer
}
type UnsignedQuantity s = Refined NonNegative (Quantity s)
mkQuantity :: KnownNat s => Scientific -> Quantity s
mkQuantityLossless :: (KnownNat s, MonadError String m) => Scientific -> m (Quantity s)
roundQuantity :: KnownNat k => Quantity (n + k) -> Quantity n
times :: (KnownNat s, KnownNat k) => Quantity s -> Quantity k -> Quantity s
timesLossless :: (KnownNat s, KnownNat k) => Quantity s -> Quantity k -> Quantity (s + k)
mkQuantityAux :: forall s. KnownNat s => Scientific -> Quantity s
roundScientific :: Int -> Scientific -> Scientific

Data Definition

newtype Quantity (s :: Nat) Source #

Type encoding for quantity values with a given scaling (digits after the decimal point).

>>> 42 :: Quantity 0
42
>>> 42 :: Quantity 1
42.0
>>> 42 :: Quantity 2
42.00
>>> 41 + 1 :: Quantity 2
42.00
>>> 43 - 1 :: Quantity 2
42.00
>>> 2 * 3 * 7 :: Quantity 2
42.00
>>> negate (-42) :: Quantity 2
42.00
>>> abs (-42) :: Quantity 2
42.00
>>> signum (-42) :: Quantity 2
-1.00
>>> fromInteger 42 :: Quantity 2
42.00
>>> mkQuantity 0.415 :: Quantity 2
0.42
>>> mkQuantity 0.425 :: Quantity 2
0.42
>>> mkQuantityLossless 0.42 :: Either String (Quantity 2)
Right 0.42
>>> mkQuantityLossless 0.415 :: Either String (Quantity 2)
Left "Underflow while trying to create quantity: 0.415"

Constructors

MkQuantity
Fields unQuantity :: Decimal RoundHalfEven s Integer

Instances

Instances details

Lift (Quantity s :: Type) Source #	`Lift` instance for `Quantity`.
Instance details Defined in Haspara.Quantity Methods lift :: Quantity s -> Q Exp # liftTyped :: Quantity s -> Q (TExp (Quantity s)) #
Eq (Quantity s) Source #
Instance details Defined in Haspara.Quantity Methods (==) :: Quantity s -> Quantity s -> Bool # (/=) :: Quantity s -> Quantity s -> Bool #
KnownNat s => Fractional (Arith (Quantity s)) Source #	Fractional arithmetic over `Quantity` values. `>>>` `import Numeric.Decimal``>>>` `arithM (fromRational 0.42) :: Either SomeException (Quantity 2)`Right 0.42 `>>>` `arithM (fromRational 0.415) :: Either SomeException (Quantity 2)`Left PrecisionLoss (83 % 200) to 2 decimal spaces `>>>` `arithM $ (fromRational 0.84) / (fromRational 2) :: Either SomeException (Quantity 2)`Right 0.42 `>>>` `arithM $ (fromRational 0.42) / (fromRational 0) :: Either SomeException (Quantity 2)`Left divide by zero `>>>` `let a = 84 :: Quantity 2``>>>` `let b = 2 :: Quantity 2``>>>` `let c = 0 :: Quantity 2``>>>` `arithM (Arith a / Arith b) :: Either SomeException (Quantity 2)`Right 42.00 `>>>` `arithM (Arith a / Arith b / Arith c) :: Either SomeException (Quantity 2)`Left divide by zero
Instance details Defined in Haspara.Quantity Methods (/) :: Arith (Quantity s) -> Arith (Quantity s) -> Arith (Quantity s) # recip :: Arith (Quantity s) -> Arith (Quantity s) # fromRational :: Rational -> Arith (Quantity s) #
KnownNat s => Num (Arith (Quantity s)) Source #	Numeric arithmetic over `Quantity` values. `>>>` `import Numeric.Decimal``>>>` `let a = Arith (mkQuantity 10) + Arith (mkQuantity 32) :: Arith (Quantity 2)``>>>` `arithMaybe a`Just 42.00 `>>>` `arithM (41 + 1) :: Either SomeException (Quantity 2)`Right 42.00 `>>>` `arithM (43 - 1) :: Either SomeException (Quantity 2)`Right 42.00 `>>>` *`arithM (2 3 * 7) :: Either SomeException (Quantity 2)`Right 42.00 `>>>` `arithM (signum 42) :: Either SomeException (Quantity 2)`Right 1.00 `>>>` `arithM (signum (-42)) :: Either SomeException (Quantity 2)`Right -1.00 `>>>` `arithM (abs 42) :: Either SomeException (Quantity 2)`Right 42.00 `>>>` `arithM (abs (-42)) :: Either SomeException (Quantity 2)`Right 42.00 `>>>` `arithM (fromInteger 42) :: Either SomeException (Quantity 2)`**Right 42.00
Instance details Defined in Haspara.Quantity Methods (+) :: Arith (Quantity s) -> Arith (Quantity s) -> Arith (Quantity s) # (-) :: Arith (Quantity s) -> Arith (Quantity s) -> Arith (Quantity s) # (*) :: Arith (Quantity s) -> Arith (Quantity s) -> Arith (Quantity s) # negate :: Arith (Quantity s) -> Arith (Quantity s) # abs :: Arith (Quantity s) -> Arith (Quantity s) # signum :: Arith (Quantity s) -> Arith (Quantity s) # fromInteger :: Integer -> Arith (Quantity s) #
KnownNat s => Num (Quantity s) Source #
Instance details Defined in Haspara.Quantity Methods (+) :: Quantity s -> Quantity s -> Quantity s # (-) :: Quantity s -> Quantity s -> Quantity s # (*) :: Quantity s -> Quantity s -> Quantity s # negate :: Quantity s -> Quantity s # abs :: Quantity s -> Quantity s # signum :: Quantity s -> Quantity s # fromInteger :: Integer -> Quantity s #
Ord (Quantity s) Source #
Instance details Defined in Haspara.Quantity Methods compare :: Quantity s -> Quantity s -> Ordering # (<) :: Quantity s -> Quantity s -> Bool # (<=) :: Quantity s -> Quantity s -> Bool # (>) :: Quantity s -> Quantity s -> Bool # (>=) :: Quantity s -> Quantity s -> Bool # max :: Quantity s -> Quantity s -> Quantity s # min :: Quantity s -> Quantity s -> Quantity s #
KnownNat s => Show (Quantity s) Source #	`Show` instance for `Quantity`. `>>>` `show (42 :: Quantity 2)`"42.00" `>>>` `42 :: Quantity 2`42.00
Instance details Defined in Haspara.Quantity Methods showsPrec :: Int -> Quantity s -> ShowS # show :: Quantity s -> String # showList :: [Quantity s] -> ShowS #
Generic (Quantity s) Source #
Instance details Defined in Haspara.Quantity Associated Types type Rep (Quantity s) :: Type -> Type # Methods from :: Quantity s -> Rep (Quantity s) x # to :: Rep (Quantity s) x -> Quantity s #
KnownNat s => ToJSON (Quantity s) Source #	`ToJSON` instance for `Quantity`. `>>>` `Aeson.encode (mkQuantity 0.42 :: Quantity 2)`"0.42"
Instance details Defined in Haspara.Quantity Methods toJSON :: Quantity s -> Value # toEncoding :: Quantity s -> Encoding # toJSONList :: [Quantity s] -> Value # toEncodingList :: [Quantity s] -> Encoding #
KnownNat s => FromJSON (Quantity s) Source #	`FromJSON` instance for `Quantity`. `>>>` `Aeson.decode "0.42" :: Maybe (Quantity 2)`Just 0.42 `>>>` `Aeson.decode "0.415" :: Maybe (Quantity 2)`Just 0.42 `>>>` `Aeson.decode "0.425" :: Maybe (Quantity 2)`Just 0.42
Instance details Defined in Haspara.Quantity Methods parseJSON :: Value -> Parser (Quantity s) # parseJSONList :: Value -> Parser [Quantity s] #
type Rep (Quantity s) Source #
Instance details Defined in Haspara.Quantity type Rep (Quantity s) = D1 ('MetaData "Quantity" "Haspara.Quantity" "haspara-0.0.0.2-AxwfIaY3JAe5J0iuX9jCcl" 'True) (C1 ('MetaCons "MkQuantity" 'PrefixI 'True) (S1 ('MetaSel ('Just "unQuantity") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Decimal RoundHalfEven s Integer))))

type UnsignedQuantity s = Refined NonNegative (Quantity s) Source #

Type definition for unsigned Quantity values.

Smart Constructors

mkQuantity :: KnownNat s => Scientific -> Quantity s Source #

Constructs Quantity values from Scientific values in a lossy way.

This function uses mkQuantityAux in case that the lossless attempt fails. We could have used mkQuantityAux directly. However, mkQuantityAux is doing too much (see roundScientific). Therefore, we are first attempting a lossless construction (see mkQuantityLossless) and we fallback to mkQuantityAux in case the lossless construction fails.

>>> mkQuantity 0 :: Quantity 0
0
>>> mkQuantity 0 :: Quantity 1
0.0
>>> mkQuantity 0 :: Quantity 2
0.00
>>> mkQuantity 0.04 :: Quantity 1
0.0
>>> mkQuantity 0.05 :: Quantity 1
0.0
>>> mkQuantity 0.06 :: Quantity 1
0.1
>>> mkQuantity 0.14 :: Quantity 1
0.1
>>> mkQuantity 0.15 :: Quantity 1
0.2
>>> mkQuantity 0.16 :: Quantity 1
0.2
>>> mkQuantity 0.04 :: Quantity 2
0.04
>>> mkQuantity 0.05 :: Quantity 2
0.05
>>> mkQuantity 0.06 :: Quantity 2
0.06
>>> mkQuantity 0.14 :: Quantity 2
0.14
>>> mkQuantity 0.15 :: Quantity 2
0.15
>>> mkQuantity 0.16 :: Quantity 2
0.16
>>> mkQuantity 0.04 :: Quantity 3
0.040
>>> mkQuantity 0.05 :: Quantity 3
0.050
>>> mkQuantity 0.06 :: Quantity 3
0.060
>>> mkQuantity 0.14 :: Quantity 3
0.140
>>> mkQuantity 0.15 :: Quantity 3
0.150
>>> mkQuantity 0.16 :: Quantity 3
0.160

mkQuantityLossless :: (KnownNat s, MonadError String m) => Scientific -> m (Quantity s) Source #

Constructs Quantity values from Scientific values in a lossy way.

>>> mkQuantityLossless 0 :: Either String (Quantity 0)
Right 0
>>> mkQuantityLossless 0 :: Either String (Quantity 1)
Right 0.0
>>> mkQuantityLossless 0 :: Either String (Quantity 2)
Right 0.00
>>> mkQuantityLossless 0.04 :: Either String (Quantity 1)
Left "Underflow while trying to create quantity: 4.0e-2"
>>> mkQuantityLossless 0.05 :: Either String (Quantity 1)
Left "Underflow while trying to create quantity: 5.0e-2"
>>> mkQuantityLossless 0.06 :: Either String (Quantity 1)
Left "Underflow while trying to create quantity: 6.0e-2"
>>> mkQuantityLossless 0.14 :: Either String (Quantity 1)
Left "Underflow while trying to create quantity: 0.14"
>>> mkQuantityLossless 0.15 :: Either String (Quantity 1)
Left "Underflow while trying to create quantity: 0.15"
>>> mkQuantityLossless 0.16 :: Either String (Quantity 1)
Left "Underflow while trying to create quantity: 0.16"
>>> mkQuantityLossless 0.04 :: Either String (Quantity 2)
Right 0.04
>>> mkQuantityLossless 0.05 :: Either String (Quantity 2)
Right 0.05
>>> mkQuantityLossless 0.06 :: Either String (Quantity 2)
Right 0.06
>>> mkQuantityLossless 0.14 :: Either String (Quantity 2)
Right 0.14
>>> mkQuantityLossless 0.15 :: Either String (Quantity 2)
Right 0.15
>>> mkQuantityLossless 0.16 :: Either String (Quantity 2)
Right 0.16
>>> mkQuantityLossless 0.04 :: Either String (Quantity 3)
Right 0.040
>>> mkQuantityLossless 0.05 :: Either String (Quantity 3)
Right 0.050
>>> mkQuantityLossless 0.06 :: Either String (Quantity 3)
Right 0.060
>>> mkQuantityLossless 0.14 :: Either String (Quantity 3)
Right 0.140
>>> mkQuantityLossless 0.15 :: Either String (Quantity 3)
Right 0.150
>>> mkQuantityLossless 0.16 :: Either String (Quantity 3)
Right 0.160

Utilities

roundQuantity :: KnownNat k => Quantity (n + k) -> Quantity n Source #

Rounds given quantity by k digits.

>>> roundQuantity (mkQuantity 0.415 :: Quantity 3) :: Quantity 2
0.42
>>> roundQuantity (mkQuantity 0.425 :: Quantity 3) :: Quantity 2
0.42

times :: (KnownNat s, KnownNat k) => Quantity s -> Quantity k -> Quantity s Source #

Multiplies two quantities with different scales and rounds back to the scale of the frst operand.

>>> times (mkQuantity 0.42 :: Quantity 2) (mkQuantity 0.42 :: Quantity 2)
0.18

timesLossless :: (KnownNat s, KnownNat k) => Quantity s -> Quantity k -> Quantity (s + k) Source #

Multiplies two quantities with different scales.

>>> timesLossless (mkQuantity 0.42 :: Quantity 2) (mkQuantity 0.42 :: Quantity 2)
0.1764

Internal

mkQuantityAux :: forall s. KnownNat s => Scientific -> Quantity s Source #

Auxiliary function for constructing Quantity values.

See mkQuantity why we need this function and why we haven't used it as the direct implementation of mkQuantity.

Call-sites should avoid using this function directly due to its performance characteristics.

roundScientific :: Int -> Scientific -> Scientific Source #

Rounds a given scientific into a new scientific with given max digits after decimal point.

This uses half-even rounding method.

>>> roundScientific 0 0.4
0.0
>>> roundScientific 0 0.5
0.0
>>> roundScientific 0 0.6
1.0
>>> roundScientific 0 1.4
1.0
>>> roundScientific 0 1.5
2.0
>>> roundScientific 0 1.6
2.0
>>> roundScientific 1 0.04
0.0
>>> roundScientific 1 0.05
0.0
>>> roundScientific 1 0.06
0.1
>>> roundScientific 1 0.14
0.1
>>> roundScientific 1 0.15
0.2
>>> roundScientific 1 0.16
0.2
>>> roundScientific 1 3.650
3.6
>>> roundScientific 1 3.740
3.7
>>> roundScientific 1 3.749
3.7
>>> roundScientific 1 3.750
3.8
>>> roundScientific 1 3.751
3.8
>>> roundScientific 1  3.760
3.8
>>> roundScientific 1 (-3.650)
-3.6
>>> roundScientific 1 (-3.740)
-3.7
>>> roundScientific 1 (-3.749)
-3.7
>>> roundScientific 1 (-3.750)
-3.8
>>> roundScientific 1 (-3.751)
-3.8
>>> roundScientific 1 (-3.760)
-3.8

TODO: Refactor to improve the performance of this function.

Orphan instances

Lift (Decimal RoundHalfEven s Integer :: Type) Source #

Orphan Lift instance for Quantity.

TODO: Avoid having an orphan instance for Decimal r s p?

Instance details

Methods

lift :: Decimal RoundHalfEven s Integer -> Q Exp #

liftTyped :: Decimal RoundHalfEven s Integer -> Q (TExp (Decimal RoundHalfEven s Integer)) #