Changelog

0.1.0 (2026-09-20)

Initial release.

• Hoare.State: a behaviour naming the status that tags a record, the reason when it does not, and the properties that refine it into a struct of witnesses; match/2 and match_any/2 build that struct or say why not.
• Hoare.Transition: from and to states, guards and effects composed as Kleisli arrows; run/4 checks, performs the effects, then commits through the store in one locked transaction with a from re-check and a to assertion. Bare effects are idempotent and retried by re-running; effects paired with an undo are reverted newest first when anything after them fails. A record already in to converges only when every completed effect was bare.
• Hoare.Store: the three operations the commit needs, transact_with_lock/2, fetch/2 and update/1.
• Hoare.Result: bind/2, kleisli/1, tap_ok/2, tap_error/2, map_error/2 over tagged tuples.