High performance JSONPath queries for Swift

/// Each call to Sextant's query(values: ) will return an array on success and nil on failure
func testSimple0() {
    let json = #"["Hello","World"]"#
    guard let results = json.query(values: "$[0]") else { return XCTFail() }
    XCTAssertEqualAny(results[0], "Hello")
}

/// You can avoid the provided extensions and call query on the Sextant singleton directly
func testSimple1() {
    let json = #"["Hello","World"]"#
    guard let jsonData = json.data(using: .utf8) else { return }
    guard let jsonObject = try? JSONSerialization.jsonObject(with: jsonData, options: []) else { return }
    guard let results = Sextant.shared.query(jsonObject, values: "$[0]") else { return XCTFail() }
    XCTAssertEqualAny(results[0], "Hello")
}

/// Works with any existing JSON-like structure
func testSimple2() {
    let data = [ "Hello", "World" ]
    guard let results = data.query(values: "$[0]") else { return XCTFail() }
    XCTAssertEqualAny(results[0], "Hello")
}

/// Automatically covert to simple tuples
func testSimple3() {
    let json = #"{"name":"Rocco","age":42}"#
    
    guard let person: (name: String?, age: Int?) = json.query("$.['name','age']") else { return XCTFail() }
    XCTAssertEqual(person.name, "Rocco")
    XCTAssertEqual(person.age, 42)
}

/// Supports Decodable structs
func testSimple4() {
    let json = #"{"data":{"people":[{"name":"Rocco","age":42},{"name":"John","age":12},{"name":"Elizabeth","age":35},{"name":"Victoria","age":85}]}}"#
    
    class Person: Decodable {
        let name: String
        let age: Int
    }
    
    guard let persons: [Person] = json.query("$..[?(@.name)]") else { return XCTFail() }
    XCTAssertEqual(persons[0].name, "Rocco")
    XCTAssertEqual(persons[0].age, 42)
    XCTAssertEqual(persons[2].name, "Elizabeth")
    XCTAssertEqual(persons[2].age, 35)
}

/// Easily combine results from multiple queries
func testSimple5() {
    let json1 = #"{"error":"Error format 1"}"#
    let json2 = #"{"errors":[{"title:":"Error!","detail":"Error format 2"}]}"#
            
    let queries: [String] = [
        "$.error",
        "$.errors[0].detail",
    ]
    
    XCTAssertEqualAny(json1.query(string: queries), "Error format 1")
    XCTAssertEqualAny(json2.query(string: queries), "Error format 2")
}