changeset

Stateful monad transformer based on monoidal actions

Stackage Nightly 2026-06-30:	0.2.2
Latest on Hackage:	0.2.2

See all snapshots changeset appears in

MIT licensed by Manuel Bärenz

Maintained by [email protected]

This version can be pinned in stack with:changeset-0.2.2@sha256:f14606db219fc85ca785ca26a6cf12dea9c6082d8a3330be5009e6c199f02940,3177

Module documentation for 0.2.2

Control
- Control.Monad
  - Control.Monad.Changeset
    - Control.Monad.Changeset.Class
  - Control.Monad.Trans
    - Control.Monad.Trans.Changeset
Data
- Data.Monoid
  - Data.Monoid.RightAction
    - Data.Monoid.RightAction.Coproduct
    - Data.Monoid.RightAction.Generic

Depends on 11 packages(full list with versions):

base, containers, indexed-traversable, mmorph, monoid-extras, mtl, profunctors, semialign, these, transformers, witherable

Used by 6 packages in nightly-2026-06-30(full list with versions):

automaton, changeset-containers, changeset-lens, changeset-reflex, changeset-time, time-domain

A general state monad transformer with separate types for the state and the possible changes. It can be defined for any monoid action. The monoid represents "changes", "updates", "edits" or "diffs" on the state. The changeset ecosystem has support for standard containers and optics from lens by providing the packages changeset-containers and changeset-lens.

Changes

Revision history for changeset

0.2.2

Add record field for SetTo

0.2.1

Fix instance overlapping in some cases

0.2

Support GHC 9.12
Drop support for GHC < 9.2
Add SetTo
Require RightAction as superclass for RightTorsor
Add SeqEdit
Add helpers changing, changed, relativeTo

0.1.1

Add support for generic deriving
Add RightTorsor class
Add support for FunctorWithIndex, Semialign, and Filterable
Default methods for MonadChangeset
Document MonadChangeset laws