double-conversion: Fast conversion between double precision floating point and text

[ bsd3, library, text ] [ Propose Tags ]
Dependencies base (==4.*), bytestring, ghc‑prim, integer (==0.1.*), integer‑gmp (>=0.2), text (>= [details]
License BSD-3-Clause
Author Bryan O'Sullivan <>
Maintainer Bryan O'Sullivan <>
Category Text
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Uploaded by BryanOSullivan at Mon Dec 31 22:10:18 UTC 2012
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A library that performs fast, accurate conversion between double precision floating point and text.

This library is implemented as bindings to the C++ double-conversion library written by Florian Loitsch at Google:

The Text versions of these functions are about 30 times faster than the default show implementation for the Double type.

The ByteString versions are slower than the Text versions; roughly half the speed. (This seems to be due to the cost of allocating ByteString values via malloc.)

As a final note, be aware that the bytestring-show package is about 50% slower than simply using show.

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Welcome to double-conversion

double-conversion is a fast Haskell library for converting between double precision floating point numbers and text strings. It is implemented as a binding to the V8-derived C++ double-conversion library.

Join in!

We are happy to receive bug reports, fixes, documentation enhancements, and other improvements.

Please report bugs via the github issue tracker.

Master git repository:

  • git clone git://

There's also a Mercurial mirror:

  • hg clone

(You can create and contribute changes using either git or Mercurial.)


This library is written and maintained by Bryan O'Sullivan,