State accepts only Type as key - explain in docs

[Akirathan]

The following code fails on Uninitialized_State panic:

main =
  State.run "my_state"  42 <|
    State.get "my_state"

This is because in both cases "my_state" is a different instance of Text and we do not have equals method implemented on Text. See the javadoc of DynamicObjectLibrary:

Property keys are compared using object identity (`==`) first and then `Object.equals(Object)`. It is
therefore recommended to use the same string/key instances for each access of the property in order
to avoid pulling in `equals`.

Putting types as keys works because types are singletons. So the following works:

type My_Type
main =
  State.run My_Type 42 <|
    State.get My_Type

Ideally, we should compare keys with EqualsNode, at least on the slow path. Or update the documentation of State methods.

[jdunkerley]

Can we make it so that the methods throw and error if the key is not a type object.

[enso-bot]

Jaroslav Tulach reports a new STANDUP for yesterday (2023-08-15):

Progress: - State & Type PR: #7585

• merged: Encapsulating array-like data and operations into a single package #7544
• merged Avoid using a (warnings) Library on this #7525
• review logging rework: Replace a custom logger with off the shelf implementation #7559 (review)
• review Column.round: Convert in-memory Column.round to Java #7521 (review)
• planning meeting It should be finished by 2023-08-17.

Next Day: Towards Python Interop & TCK

[enso-bot]

Jaroslav Tulach reports a new STANDUP for yesterday (2023-08-16):

Progress: - review Column.round: #7521 (review)

• fixing State in SQL: https://github.com/enso-org/enso/pull/7585/files#r1295366131
• merged Use only Type instances as keys for State #7585
• Java Enum match: cc91342
• approving Benchmarks: Ability to invoke all std benchmarks via jmh #7519 (review)
• triaging, standups, meetings It should be finished by 2023-08-17.

Next Day: Towards Python Interop & TCK

GitHub

Use only Type instances as keys for State by JaroslavTulach · Pull Request #7585 · enso-org/enso

Pull Request Description Fixes #7572 by requiring keys to be Type instances. Checklist Please ensure that the following checklist has been satisfied before submitting the PR:

All code follows the...