@hackage FloatingHex0.5

Read and write hexadecimal floating point numbers

FloatingHex: Read/Write Hexadecimal floats

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Hexadecimal Floats

For syntax reference, see: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf, pages 57-58. We slightly diverge from the standard and do not allow for the "floating-suffix," as the type inference of Haskell makes this unnecessary. Some examples are:


This format allows for concise and precise string representation for floating point numbers. Note that you need the QuasiQuotes extension of GHC to be able to write these literals.


{-# LANGUAGE QuasiQuotes #-}
import Data.Numbers.FloatingHex

-- expressions
f :: Double
f = [hf|0x1.f44abd5aa7ca4p+25|]

-- patterns
g :: Float -> String
g [hf|0x1p1|]  = "two!"
g [hf|0x1p-1|] = "half!"
g d            = "something else: " ++ show d

-- showing hexadecimal floats
test = showHFloat [hf|0x1.f44abd5aa7ca4p+25|] ""

(Note that while the quasiquoter allows for floating-point patterns, it is usually not a good idea to use floating-point literals in pattern matching.)


The following people reported bugs, provided comments/feedback, or contributed to the development of FloatingHex in various ways: Herbert Valerio Riedel.