refactor: hide format deserializer state type #34
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This change hides away the state of the context object passed around between deserialization calls, which makes the `Serde.De.t` value take a single type parameter for the type of value it is deserializing into. That means that `(Serde_json.De.state, User.t) Serde.De.t` becomes `User.t Serde.De.t` – this frees the user to swap out the format module at runtime, and should make type errors simpler as well.
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Confirmed with the bug repro repo (leostera/serde-de-state-bug-repr@174d240) and with @emilpriver that this works for DbCaml too. Merging 🚀 |
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tldr: go from
(Serde_json.De.state, User.t) Serde.De.ttoUser.t Serde.De.tThis refactor should make the ergonomics of Serde much better for library authors that need to provide flexibility on the format deserializer type, by making the format deserializer state type go away or be hidden at least from the user facing code.
We've first observed this when working on DbCaml with @emilpriver and noticed that a common error was unifying the types of the state of the format deserializer, which wasn't known in some cases by design, to allow a user to switch up which database format deserializer module they wanted to use (Postgres, SQLite, etc).