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iOS Error Handling in Swift 2.0 Error Handling Handling Errors

Posted by Anton Melekh
Anton Melekh
2,729 Points

Just wondering if it's correct to solve the task 1 of 3 in this challenge by writing code this way:

Logic seems to be correct for me and playground shows no errors, however, code isn't accepted by Treehouse. Can you please explain?

error.swift 
enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

struct Parser {
    var data: [String : String?]?

    func parse(dict: [String: String]) throws {
        guard data != nil else {
            throw ParserError.EmptyDictionary
        }
        guard dict["someKey"] != nil else {
            throw ParserError.InvalidKey
        }
    }
}

let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)

1 Answer

Safwat Shenouda
Safwat Shenouda
12,362 Points

Hi Anton,

There is some confusion in function parse, it should not take any parametrs and just operate on data dictionary included. so please change it like this and it will be accepted. I tried it:

enum ParserError: ErrorType {
    case EmptyDictionary
    case InvalidKey
}

struct Parser {
    var data: [String : String?]?

    func parse() throws {
        guard data != nil else {
            throw ParserError.EmptyDictionary
        }
        guard data!.keys.contains("someKey") else {
            throw ParserError.InvalidKey
        }
    }
}



let data: [String : String?]? = ["someKey": nil]
let parser = Parser(data: data)