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iOS Error Handling in Swift Error Handling Handling Errors

Posted by Noe Arzate
.a{fill-rule:evenodd;}techdegree
Noe Arzate
Python Web Development Techdegree Student 6,077 Points

how to call parse method in try/catch block?

I can't seem to know how to call parse method in try/catch block. Any assistance with this challenge is greatly appreciated.

error.swift 
enum ParserError: Error {
  case emptyDictionary
  case invalidKey
}

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

  func parse() throws {
    guard let data = data else {
      throw ParserError.emptyDictionary
    }

    guard data["someKey"] != nil else {
      throw ParserError.invalidKey
    }
  }
}

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

do {

  } catch ParserError.emptyDictionary {
    print("empty dictionary") 
}
Jason Marcial
Jason Marcial
8,162 Points
Jason Marcial
Jason Marcial
8,162 Points

Hi Noe, In order to call the parse method for this challenge, you'll achieve it using 'try' before calling the method, since parse() is a throwing function.

do {
    try parser.parse()
} catch ParserError.emptyDictionary {
    print("empty dictionary")
} catch ParserError.invalidKey {
    print("invalid key")
}

I hope this code finds helpful ?

Noe Arzate
.a{fill-rule:evenodd;}techdegree
Noe Arzate
Python Web Development Techdegree Student 6,077 Points

Yes, that did it. Now, I'm not sure how to pattern match on specific error to display better error message. Again, your assistance is greatly appreciated.