jrec — anonymous records for busy people

Based on superrecord, but simplified. No automatic field reordering. No GHCJS bits inside. Easier to hack on.

Benefits

• Nice construction syntax:

  Rec (#id := 18853, #orderId := "MG13-233")

• Provides Generic instances out of the box. Aeson, etc can't believe these aren't normal records! Anything Generic-derived just works.

• Provides generic-lens and generic-optics instances out of the box. Due to those custom instances, we support polymorphic updates.

• O(1) field access, O(n) construction.

• PureScript-style partial records — if you have a Rec ("foo" := Int ': rest), HasField "foo" will work just fine.

Developing

IDE support is available inside nix-shell. For example, if you use VS Code, you may launch it as:

nix-shell --run "code ."

Tests

Run bin/test for fast-reloading tests. When library sources change, the test script will reload instantly and re-run the tests.

TODOs

• Documentation.
• Expose all internals.
• -- NOTE: doesn't use 'KeyDoesNotExist' — fix this.
• RemoveAccessTo — can we get rid of it?

Acknowledgement

• The JRec.Internal module is entirely based on the code from superrecord.