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

[ bsd2, bsd3, library, text ] [ Propose Tags ]

A library that performs fast, accurate conversion between floating point and text.

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

Now it can convert single precision numbers, and also it can create Builder, instead of bytestring or text.

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

The ByteString versions are have very close speed to the Text versions;

Builder versions (both for Text and Bytestring) are slower on single value, but they are much faster on large number of values (up to 20x faster on list with 20000 doubles).

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

[Skip to Readme]


Manual Flags


operate in developer mode

Automatic Flags

embed the C++ double_conversion library


Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info


Maintainer's Corner

Package maintainers

For package maintainers and hackage trustees


  • No Candidates
Versions [RSS],,,,,,,,,,,,, (info)
Dependencies base (>=4 && <5), bytestring, ghc-prim, system-cxx-std-lib (==1.0), text (>= [details]
License BSD-2-Clause
Author Bryan O'Sullivan <>
Maintainer Bryan O'Sullivan <>
Category Text
Home page
Bug tracker
Source repo head: git clone
Uploaded by Haskell_Mouse at 2024-02-11T15:24:21Z
Distributions Arch:, Debian:, Fedora:, FreeBSD:, LTSHaskell:, NixOS:, Stackage:
Reverse Dependencies 33 direct, 7734 indirect [details]
Downloads 50062 total (662 in the last 30 days)
Rating (no votes yet) [estimated by Bayesian average]
Your Rating
  • λ
  • λ
  • λ
Status Docs uploaded by user
Build status unknown [no reports yet]

Readme for double-conversion-

[back to package description]

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://


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