| Copyright | (c) Justus Sagemüller 2017 |
|---|---|
| License | GPL v3 |
| Maintainer | (@) jsagemue $ uni-koeln.de |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Safe |
| Language | Haskell2010 |
Numeric.Literals.Decimal
Contents
Description
- data FractionalLit
- pattern (:%) :: Integer -> Integer -> FractionalLit
- pattern Scientific :: Int -> [B₁₀Digit] -> Int -> FractionalLit
- data B₁₀Digit
Documentation
data FractionalLit Source #
A type whose Fractional instance gives a somewhat reliable indication whether
a value was actually defined as an integer or a ratio, or as a decimal-fraction
literal. This is useful to know for a type that supports both exact fraction
values and more floating-point-like / physical values; it allows avoiding
issues like 0.524 showing up as 589971551185535/1125899906842624, or conversely
7/23 as 0.30434782608695654. Both of these scenarios are quite awkward.
Instances
| Eq FractionalLit Source # | |
| Fractional FractionalLit Source # | Despite the name, |
| Num FractionalLit Source # | |
| Show FractionalLit Source # | |
pattern (:%) :: Integer -> Integer -> FractionalLit Source #
Construct an exact fraction. The values behave like Rational, until combined
– e.g. added – with a Scientific value (which has an implicit
measurement-uncertainty, and that carries over to the result).
pattern Scientific :: Int -> [B₁₀Digit] -> Int -> FractionalLit Source #
Construct a scientific number of the form m.n * 10^e, where m and e are
integers and n is a list of digits after the decimal point. The result
is considered to be only exact up to the precision indicated by the number
of digits. I.e. Scientific 2 [4,8,3] (-4) basically means 2.483×10⁻⁴ ± 10⁻⁷,
The Fractional instance allows these values to be written in the standard
2.483e-4 notation. Note that this cannot completely reconstruct the written
form, e.g. 12.483e-4 will actually show up as Scientific 1 [2,4,8,3] (-3).
Leading and trailing zeroes are always ignored.