vic/typeset

---

vic/typeset.json

{
  "defaultBranch": "main",
  "description": "An Scala type-indexed set, checked at compile time.",
  "fullName": "vic/typeset",
  "homepage": "",
  "language": "Scala",
  "name": "typeset",
  "pushedAt": "2025-07-15T04:35:58Z",
  "stargazersCount": 1,
  "updatedAt": "2025-07-15T04:36:02Z",
  "url": "https://github.com/vic/typeset"
}

typeset

An Scala Type indexed set checked at compile time.

a TypeSet is similar to ZIO’s Has[_] type but without any reflection need.

Adding to your project.

Jars are available for all versions and commits at Jitpack.io.

Usage

Creating a TypeSet is always done by prepending something to TNil, which represent the empty TypeSet.

import typeset.*

val x = "Hello" :+: TNil

Of course, being a Set, you can’t duplicate types of values on it.

// val bad = "Hello" :+: "World" :+: TNil // This wont compile!!

The type of the set can be re-arrenged on the left side and any combination containing the same types should be valid.

val a: String :+: Boolean :+: Int :+: TNil = "Hello" :+: true :+: 42 :+: TNil
val b: Int :+: String :+: Boolean :+: TNil = a // types are the same.

TypeSets can be joined together if they contained types do not cause duplicates.

val a = 1 :+: TNil
val b = true :+: TNil
val c = a :+: b // Has type Int :+: Boolean :+: TNil

Once created, you can obtain the value of a type from a Set.

val a = true :+: "Hello" :+: TNil
val x: String = a.get[String] // Returns "Hello"

Removing a type returns it’s current value and another collapsed set without the type present.

val a = true :+: "Hello" :+: TNil
val (x: String, b) = a.drop[String]!() // type of b is Boolean :+: TNil

That’s pretty much it. For more examples you can see the [test code]!(typeset/test/src).

Contributing

All contributions are welcome, just please be kind and repectful of other people’s time.

For Building, you will need mill installed.

mill __.test # This will run all tests