boolean

Negation of a Boolean singleton type.

val notFalse: ![false] = true
val notTrue: ![true] = false

Conjunction of two Boolean singleton types.

val a: true && true = true
val b: false && true = false

Exclusive disjunction of two Boolean singleton types.

val a: true ^ true = false
val b: false ^ true = true

Disjunction of two Boolean singleton types.

val a: true || false = true
val b: false || false = false