envparse

Parse environment variables

https://supki.github.io/envparse

LTS Haskell 23.27:0.6.0
Stackage Nightly 2025-07-12:0.6.0
Latest on Hackage:0.6.0

See all snapshots envparse appears in

BSD-3-Clause licensed by Matvey Aksenov
Maintained by [email protected]
This version can be pinned in stack with:envparse-0.6.0@sha256:df4483a7cf9829349b65248e2d6d692a83da807ae2cc3908013d3787a8d17251,2849

Module documentation for 0.6.0

  • Env
    • Env.Internal
      • Env.Internal.Error
      • Env.Internal.Free
      • Env.Internal.Help
      • Env.Internal.Parser
      • Env.Internal.Val
Depends on 2 packages(full list with versions):
base, containers
Used by 1 package in nightly-2025-07-12(full list with versions):
Blammo

envparse

Build status

optparse-applicative, but for environment variables

See example/Main.hs for an executable example

As to why anyone would want to use environment to configure their applications, here’s what some folks think about it.

Changes

0.6.0

A PVP-compliant re-release of 0.5.2 with no changes. (I missed a breaking change back in 0.5.1.)

0.5.2

0.5.1

0.5

0.4.1

  • Supported GHC 8.4.3.

0.4

  • Supported GHC 8.0.1.

  • On GHC 7.8 and newer, as a secutiry measure, all declared variables are unset by the end of a successful parse. If you want to keep the variable in the environment, use the keep modifier. (https://github.com/supki/envparse/pull/7)

0.3.4

  • Added splitOn.

0.3.3

  • Removed the unnecessary AsEmpty and AsUnset constraints on the error type in the flag and switch parsers.

0.3.2

  • Added showDef.

0.3.1

  • Supported Generically derived Parsers on GHC 7.10.

0.3.0

0.2.2

  • Added helpDoc, a Parser pretty-printer for use in error messages.

0.2.1

  • Cosmetic changes in the help output.

0.2.0

  • Added prefixed.

  • Added parseOr, a slightly generalized version of parse.

  • Renamed parseTest to parsePure.

0.1.0

  • Initial release.