make ApkIndexDependency conform to ApkIndexRequirementRef

dunno if this is necessary for the graph to work but we'll see

Sources/apk/Common/ApkVersionSpecification.swift

@@ -3,22 +3,12 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-enum ApkVersionSpecification: Equatable {
+enum ApkVersionSpecification: Equatable, Hashable {
   case any
   case constraint(op: Operator, version: String)
   case conflict
 }
 
-extension ApkVersionSpecification: CustomStringConvertible {
-  var description: String {
-    switch self {
-    case .any: ""
-    case .conflict: "!"
-    case .constraint(let op, let version): "\(op)\(version)"
-    }
-  }
-}
-
 extension ApkVersionSpecification {
   enum Operator: Equatable {
     case equals

Sources/apk/Index/ApkIndexDependency.swift

@@ -9,8 +9,9 @@ struct ApkIndexDependency: ApkIndexRequirementRef {
   let name: String
   let versionSpec: ApkVersionSpecification
 
-  init(extract: String) throws(ApkRequirement.ParseError) {
-    (self.name, self.versionSpec) = try ApkRequirement.extract(blob: extract)
+  init(name: String, version spec: ApkVersionSpecification) {
+    self.name = name
+    self.versionSpec = spec
   }
 }
 

Sources/apk/Index/ApkIndexInstallIf.swift

@@ -7,7 +7,8 @@ struct ApkIndexInstallIf: ApkIndexRequirementRef {
   let name: String
   let versionSpec: ApkVersionSpecification
 
-  init(extract: String) throws(ApkRequirement.ParseError) {
-    (self.name, self.versionSpec) = try ApkRequirement.extract(blob: extract)
+  init(name: String, version spec: ApkVersionSpecification) {
+    self.name = name
+    self.versionSpec = spec
   }
 }

Sources/apk/Index/ApkIndexPackage.swift

@@ -5,7 +5,7 @@
 
 import Foundation
 
-struct ApkIndexPackage: Hashable {
+struct ApkIndexPackage: ApkIndexRequirementRef {
   let indexChecksum: ApkIndexDigest
   let name: String
   let version: String
@@ -28,6 +28,10 @@ struct ApkIndexPackage: Hashable {
 
   //TODO: Implementation
   //lazy var semanticVersion: (Int, Int, Int) = (0, 0, 0)
+
+  init(name: String, version spec: ApkVersionSpecification) {
+    fatalError("Cannot construct an ApkIndexPackage this way")
+  }
 }
 
 extension ApkIndexPackage {

Sources/apk/Index/ApkIndexProvides.swift

@@ -6,7 +6,7 @@
 struct ApkIndexProvides: ApkIndexRequirementRef {
   let name: String
 
-  init(extract: String) throws(ApkRequirement.ParseError) {
-    (self.name, _) = try ApkRequirement.extract(blob: extract)
+  init(name: String, version _: ApkVersionSpecification) {
+    self.name = name
   }
 }

Sources/apk/Index/ApkIndexRequirementRef.swift

@@ -7,7 +7,7 @@ protocol ApkIndexRequirementRef: Equatable, Hashable {
   var name: String { get }
   var invert: Bool { get }
 
-  init(extract: String) throws(ApkRequirement.ParseError)
+  init(name: String, version spec: ApkVersionSpecification)
 
   func satisfied(by other: ApkIndexPackage) -> Bool
 }
@@ -16,18 +16,11 @@ extension ApkIndexRequirementRef {
   var invert: Bool { false }
   func satisfied(by _: ApkIndexPackage) -> Bool { true }
 
-  static func == (lhs: Self, rhs: Self) -> Bool {
-    return !(lhs.name != rhs.name && !lhs.invert)
-  }
-
-  func hash(into hasher: inout Hasher) {
-    self.name.hash(into: &hasher)
-  }
-
   static func extract<T: ApkIndexRequirementRef>(_ blob: String) throws(ApkRequirement.ParseError) -> [T] {
     return try blob.components(separatedBy: " ")
       .map { token throws(ApkRequirement.ParseError) in
-        try .init(extract: token)
+        let (name, versionSpec) = try ApkRequirement.extract(blob: token)
+        return .init(name: name, version: versionSpec)
       }
   }
 }