> On Oct 1, 2017, at 8:56 AM, Dave Reed via swift-users <swift-users@swift.org>
> wrote:
>
>
>> On Sep 21, 2017, at 3:58 PM, V T via swift-users <swift-users@swift.org>
>> wrote:
>>
>> Hi there!
>>
>> Is there a best way to check if a given type conforms to numeric protocol
>> (Integer or FP) at runtime?
>>
>> func checkNumeric<T>(_ value: T) {
>> /* return true if vaiue is Integer or FP */
>> /* this will not compile: */
>> if value is Numeric {
>>
>> }
>> }
>>
>> Best regards!
>>
>> VT
>>
>
> I think the way to do it is to try casting as the type, but you can't use
> "as? Numeric" as you get:
>
> error: protocol 'Numeric' can only be used as a generic constraint because it
> has Self or associated type requirements
>
> but you could check for each specific numeric type such as:
>
> func checkNumeric<T>(_ value: T) {
> if (value as? Int != nil) || (value as? Float != nil) {
> print("numeric")
> } else {
> print("not numeric")
> }
> }
>
> checkNumeric(3)
> checkNumeric(3.0)
> checkNumeric("3")
You can also use the 'is' operator, as in 'value is Int || value is Float ||
value is Double'
--
Glenn L. Austin, Computer Wizard, AustinSoft.com
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