Need a way to define and enumerate union types.

[congwenma]

I find myself defining union types, and when trying to use them I have to explicitly use their names instead of just enumerate through them,

It seems that by having union type automatically classifying types(which is wonderful), we lost a use case of dynamically expand its content into possible test cases. Would it be too unstable to have this bit of dynamic-ality in elm?

In any case, I'm wondering how the following test case is possible in elm.

const alphabet = "abcdefghijklmnopqrstuvwxyz".split('') 
// Here's what I'd imagine would be UnionType in elm ->
//     type Alphabet = A | B | C | D | E.....
const germanAlphabet = "abcdefghijklmnopqrstuvwxyzäöüß".split('')

const expand = n => [...Array(n)]

const testSetup = (unionType) => {
  const randomTestString = expand(1000) 
    .reduce((accu) => {
       const alphabetIndex = Math.floor(Math.random() * unionType.length);
       return accu + unionType[alphabetIndex]; 
       // ^^ Can you do something like this in Elm?
    }, "");
  return randomTestString
}

const randomText = testSetup(alphabet)
const randomGermanText = testSetup(germanAlphabet)

And lets pretend that in this fictional universe, people are very proud of a letter they are assigned to, so much so that they would gladly label themselves in this fashion of elm:

type alias Person = { 
  name: String,
  letter: AlphaBet
}

[process-bot]

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[process-bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

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[evancz]

This seems like a language feature request, but I do not get it at all. We do not have any short-term plans to make changes to type declarations though, so I will close.

[evancz]

This seems like a language feature request, but I do not get it at all. We do not have any short-term plans to make changes to type declarations though, so I will close.