The Fortress Language Specification - CiteSeerX

Chapter 23
Objects
23.1 The Trait Fortress.Core.Object
The trait Object is a single root of the type hierarchy; every object in Fortress has trait Object and therefore every
object implements the methods of this trait.
trait Object extends { EquivalenceRelationObject, =, IdentityOperatorObject }
opr =(self,other: Object):Boolean
opr IDENTITY(self):Object
hash(maxval: N64): N64
hash(maxval: N32): N32
getter hashCode(): N64
toString():String
property ∀(x, y, n: N64) x = y → x.hash(n) = y.hash(n)
property ∀(x, y, n: N32) x = y → x.hash(n) = y.hash(n)
property ∀(x) x.hashCode = x.hash(2 64 − 1)
property ∀(x, y) x = y → x.toString() = y.toString()
end
23.1.1 opr =(self,other: Object): Boolean
The infix operator = (object equivalence) is used to decide whether two objects are “the same object” in the strictest
sense possible; this is described in detail in Section 10.4.
For ≠ = see Section 26.1.1.
23.1.2 opr IDENTITY(self):Object
The operator IDENTITY simply returns its argument. (This may not be terribly useful for applications programming,
but it has technical uses for specifying contracts and algebraic properties in libraries as described in Section 37.3.)
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