public protocol JSEngine {

associatedtype JSRuntime: JavaScript.JSRuntime

static func createRuntime() throws -> JSRuntime

}

public protocol JSRuntime {

associatedtype JSContext: JavaScript.JSContext

func createContext() throws -> JSContext

}

public protocol JSContext {

associatedtype JSValue: JavaScript.JSValue

func evaluate(_ script: String) throws -> JSValue

}

public protocol JSValue {

func toString() throws -> String

var isNull: Bool { get }

var isUndefined: Bool { get }

var isBool: Bool { get }

var isNumber: Bool { get }

var isString: Bool { get }

var isObject: Bool { get }

}

public enum Value {

case undefined

case string(String)

case number(Double)

case bool(Bool)

case null

}