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by vyuh 1837 days ago
Can you (or anyone) point me to the files where this `comparable` logic is implemented in elm compiler? I'll try my hand at least making Bool and Record types Comparable. Or maybe implement comparable Enumerated Type in elm which behaves mostly like custom Union Type.
2 comments
cies 1837 days ago
Even if you find the place in the `elmc` code base, fix it and make a PR: it will not be accepted. This is the walled garden aspect of Elm.

Either you accept the walls or you go with PureScript (which could be described as "Elm without the walls"; but then there is a lot more to learn and a whole plethora of frameworks where Elm has the one-to-rule-m-all-FW baked in).

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girishso 1837 days ago
Or create a fork of Elm, which I would support. I'm very happy using Elm for work over the past 3 years, but it's too limiting for advanced usage.
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cies 1837 days ago
Maybe a good elm-to-purescript transpiler, that couples with the framework this post links to, is all we need :)
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vyuh 1837 days ago
I think if someone implements this thing without breaking backward compatibility, then it will be valuable even as a fork of the original elm compiler. I think the License allows this.

Also, Evan has not closed this issue since 2015. Most probably it is about "too much work to get it right" rather than "I'm not convinced that we need it".

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cies 1837 days ago
I think type classes is how one would want to fix this. Haskell and PureScript have 'm. But them come with a lot, A LOT, of work. Especially to get the std lib to use them!

With comparability you can use the operators (<,>,<=,>=,==,/=,etc.) on various types. This is not how Elm usually works. I.e. the `map` function is different for `List.map`, `Dict.map`, `Maybe.map`, etc.

In Haskell and PS you have type classes. Some types can be mapped, some can be compared, etc. Then the type class defines what functions should be implemented for such type in order to be part of the type class.

You think it's a small change, but it is pretty much what sets Elm and PS apart. Errors can also get a lot more complex with code that leans heavily on type classes.

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pyrale 1837 days ago
It simply won't be merged.
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