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Some tests on ADTs with Scala 3
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import scala.compiletime.constValue | |
object Logic extends App: | |
// Definitions | |
enum Formula: | |
case Variable[Id <: String & Singleton](val id: Id) extends Formula | |
case True extends Formula | |
case False extends Formula | |
case And[L <: Formula, R <: Formula](left: L, right: R) extends Formula | |
case Or[L <: Formula, R <: Formula](left: L, right: R) extends Formula | |
case Not[F <: Formula](formula: F) extends Formula | |
// Sugar | |
import Formula._ | |
object Variable: | |
inline given apply[Id <: String & Singleton]: Variable[Id] = new Variable[Id](constValue[Id]) | |
import Variable.apply | |
type True = True.type | |
type False = False.type | |
type &&[L <: Formula, R <: Formula] = And[L, R] | |
type ||[L <: Formula, R <: Formula] = Or[L, R] | |
type ![F <: Formula] = Not[F] | |
extension [L <: Formula](left: L) | |
def &&[R <: Formula](right: R): L && R = And(left, right) | |
def ||[R <: Formula](right: R): L || R = Or(left, right) | |
def unary_! : ![L] = Not(left) | |
given [L <: Formula, R <: Formula](using left: L, right: R): (L && R) = left && right | |
given [L <: Formula, R <: Formula](using left: L, right: R): (L || R) = left || right | |
given [F <: Formula](using formula: F): ![F] = !formula | |
given True: Formula.True.type = True | |
given False: Formula.False.type = False | |
def $[T <: Formula](using T): T = summon[T] | |
// Tests | |
val a: (Variable["a"] && True) || ![False] = $ | |
assert(a == ((Variable["a"] && True) || !False)) | |
println($: False) |
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