ghc-scientific

"Data.Scientific" provides the number type 'Scientific'. Scientific numbers are
arbitrary precision and space efficient. They are represented using
<http://en.wikipedia.org/wiki/Scientific_notation scientific notation>.
The implementation uses a coefficient 'c :: 'Integer'' and a base-10 exponent
'e :: 'Int''. A scientific number corresponds to the 'Fractional' number:
''fromInteger' c * 10 '^^' e'.
Note that since we're using an 'Int' to represent the exponent these numbers
aren't truly arbitrary precision. I intend to change the type of the exponent
to 'Integer' in a future release.
The main application of 'Scientific' is to be used as the target of parsing
arbitrary precision numbers coming from an untrusted source. The advantages
over using 'Rational' for this are that:

A 'Scientific' is more efficient to construct. Rational numbers need to be
constructed using '%' which has to compute the 'gcd' of the 'numerator' and
'denominator'.

'Scientific' is safe against numbers with huge exponents. For example:
'1e1000000000 :: 'Rational'' will fill up all space and crash your program.
Scientific works as expected:


>>> read "1e1000000000" :: Scientific 1.0e1000000000

Also, the space usage of converting scientific numbers with huge exponents to
''Integral's' (like: 'Int') or ''RealFloat's' (like: 'Double' or 'Float') will
always be bounded by the target type.


          

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License: BSD-3-Clause
URL: https://hackage.haskell.org/package/scientific