Shuang Rimu

A blog about random stuff

Formalization of extensible unions in Elm

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Unknown author. Declarative Rule System. Unknown year. Creative Commons Attribution-ShareAlike 3.0 Unported License (NOT a CC-BY 4.0 License).

August 31, 2020


This is a follow-up to my previous post https://shuangrimu.com/posts/elm-extensible-unions.html.

Since then there’s been a lot of interest in the associated Elm Discourse thread.

Evan asked for a more formal treatment than the previous post, so here I give one.

It involves a lot of math symbols so I’ve typed it up in LaTeX and made it a PDF. The link is here