BSD-3-Clause licensed by Kamil Dworakowski
This version can be pinned in stack with:error-or-,1145

Module documentation for

Depends on 4 packages(full list with versions):
Used by 3 packages in lts-19.18(full list with versions):


Build Status

Composable, hierarchical errors.

Capture all the errors by using the Applicative instance

Add error context to results from lower level with ‘tag’

Changes (2021-06-24)

  • Renames to reduce the likelihood of name collisions on importing the module unqualified
    • rename err to failText, to suggest the use of
    • prepend ErrAcc constructors with ‘Err’ prefix
    • rename pretty to prettyErrAcc
  • Define a MonadError instance for ErrorOr (2020-12-16)

  • Mark the OK and Error patterns of ErrorOr complete for the exhaustiveness checker (2020-12-02)

  • Add tagIO