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Empty Hashes.

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This commit is contained in:
Rob Rix 2015-10-02 12:24:18 -04:00
parent 49721679b6
commit 2ab10d6b3d
1 changed files with 9 additions and 0 deletions
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9
prototype/Doubt/Hash.swift
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@ -12,6 +12,11 @@ public enum Hash: AlgebraicHashable {
/// The embedding of a raw hash value into an algebraic hash.
case Raw(Int)
/// The empty hash.
///
/// This is the right and left unit for Unordered.
case Empty
public init(_ label: String, _ hashes: Hash...) {
self = .Ordered([ Hash(label) ] + hashes)
}
@ -57,6 +62,8 @@ public enum Hash: AlgebraicHashable {
return s.hashValue
case let .Raw(i):
return i.hashValue
case .Empty:
return 0
}
}
}
@ -71,6 +78,8 @@ public func == (left: Hash, right: Hash) -> Bool {
return a == b
case let (.Raw(a), .Raw(b)):
return a == b
case (.Empty, .Empty):
return true
default:
return false
}