You need to know that the NAME of a method or function isn't just outside the
parenthesis.
The name of
func IsTextEmpty(foo : String?) -> Bool?
is
"IsTextEmpty(foo:)"
and the name of
func IsTextEmpty(text : String?) -> Bool
is
"IsTextEmpty(text:)"
The argument labels are important.
func IsTextEmpty(foo : String?) -> Bool? {
return foo?.isEmpty
}
func IsTextEmpty(text : String?) -> Bool {
guard let text = text else {
return true
}
return text.isEmpty
}
print(IsTextEmpty(foo: "1"), IsTextEmpty(text: "2"))
// prints Optional(false) false
--
C. Keith Ray
Senior Software Engineer / Trainer / Agile Coach
* http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf
> On Oct 10, 2017, at 10:27 AM, C. Keith Ray <keith...@mac.com> wrote:
>
> nope. it's the same as this example:
>
> func funny() -> Int {
> return 1
> }
>
> func funny() -> String {
> return "2"
> }
>
> print(funny()) // the compiler doesn't know which one you want.
>
> // the above doesn't compile.
> // error: forloop.playground:8:1: error: ambiguous use of 'funny()'
>
>
> You have to have some difference visible in the caller:
>
>
> func funny(useInt: Bool) -> Int {
> return 1
> }
>
> func funny(useString: Bool) -> String {
> return "2"
> }
>
> print(funny(useInt: true), funny(useString: true))
> // prints "1 2\n"
>
>
> --
> C. Keith Ray
> Senior Software Engineer / Trainer / Agile Coach
> * http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf
> <http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf>
> * https://leanpub.com/wepntk <https://leanpub.com/wepntk> <- buy my book?
>
>
>> On Oct 10, 2017, at 9:06 AM, Phil Kirby via swift-users
>> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote:
>>
>> <>2 down vote <> favorite
>> <https://stackoverflow.com/questions/46620311/overloading-methods-where-only-difference-is-optional-vs-non-optional-type#>
>>
>> Original StackOverflow post:
>>
>> https://stackoverflow.com/questions/46620311/overloading-methods-where-only-difference-is-optional-vs-non-optional-type
>>
>> <https://stackoverflow.com/questions/46620311/overloading-methods-where-only-difference-is-optional-vs-non-optional-type>
>> I was under the impression that swift can have overloaded methods that
>> differ only in the type of object that the methods return. I would think
>> that I could have two funcs with the same signature yet they differ in
>> return type.
>>
>> import Foundation
>>
>> // ambiguous use of 'IsTextEmpty(text:)'
>> func IsTextEmpty(text : String?) -> Bool? {
>> return text?.isEmpty
>> }
>>
>> func IsTextEmpty(text : String?) -> Bool {
>> guard let text = text else {
>> return true
>> }
>>
>> return text.isEmpty
>> }
>>
>> let text: String? = nil
>>
>> if let empty = IsTextEmpty(text:"text") {
>> print("Not Empty")
>> }
>>
>> if IsTextEmpty(text: text) {
>> print("Empty")
>> }
>> Here, both functions have the same input parameters but one func returns an
>> optional Bool? and the other returns a Bool. In this case I get an error:
>>
>> ambiguous use of 'IsTextEmpty(text:)'
>> If I change the name of one of the input parameters I no longer get the
>> ambiguous error:
>>
>> // Works
>> func IsTextEmpty(foo : String?) -> Bool? {
>> return foo?.isEmpty
>> }
>>
>> func IsTextEmpty(text : String?) -> Bool {
>> guard let text = text else {
>> return true
>> }
>>
>> return text.isEmpty
>> }
>>
>> let text: String? = nil
>>
>> if let empty = IsTextEmpty(foo:"text") {
>> print("Not Empty")
>> }
>>
>> if IsTextEmpty(text: text) {
>> print("Empty")
>> }
>> Shouldn't the compiler detect that they are two distinct methods even though
>> their return types are different, since an optional Bool? is a different
>> type from a non-optional Bool?
>>
>>
>> _______________________________________________
>> swift-users mailing list
>> swift-users@swift.org <mailto:swift-users@swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-users
>
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