void a(T1, T2)(T1 b, T2 c){
	// I need parameter "c" optional, but only (String or int). How can I make it without overload function?
}

On 11/28/20 6:40 PM, Marcone wrote:
> void a(T1, T2)(T1 b, T2 c){
>      // I need parameter "c" optional, but only (String or int). How can I make it without overload function?
> }

Since it's optional, T2 must have a default type. I made it 'int' below.

void a(T1, T2 = int)(T1 b, T2 c = T2.init)
if (is (T2 == string) ||
    is (T2 == int))
{
  // ...
}

void main() {
  a(1.5);
  a(2.5, "hello");
  a(3.5, 42);
  static assert(!__traits(compiles, a(4.5, 5.5)));
}

On Sunday, 29 November 2020 at 02:55:02 UTC, Ali Çehreli wrote:
> On 11/28/20 6:40 PM, Marcone wrote:
>> void a(T1, T2)(T1 b, T2 c){
>>      // I need parameter "c" optional, but only (String or int). How can I make it without overload function?
>> }
>
> Since it's optional, T2 must have a default type. I made it 'int' below.
>
> void a(T1, T2 = int)(T1 b, T2 c = T2.init)
> if (is (T2 == string) ||
>     is (T2 == int))
> {
>   // ...
> }
>
> void main() {
>   a(1.5);
>   a(2.5, "hello");
>   a(3.5, 42);
>   static assert(!__traits(compiles, a(4.5, 5.5)));
> }

Thank you! work fine!

Now my slice works fine.


// Tipo Nulo.
class None {}

// Função slice()
auto slice(T1, T2, T3 = None)(T1 conteudo, T2 inicio, T3 fim = T3.init) {
	int start, end, startlen;
	static if (is(T2 == int)) {inicio = inicio < 0 ? conteudo.length + inicio : inicio;}
	static if (is(T3 == int)) {fim = fim <= 0 ? conteudo.length + fim : fim;}
	static if (is(T2 == int)) {start = inicio;} else static if (is(T2 == string)){start = conteudo.countUntil(inicio);}
	static if (is(T2 == string)) {static if (is(T1 == string)){startlen = start + inicio.length + 1;} else {startlen = start + 1;}}
	static if (is(T3 == int)) {end = fim;} else static if (is(T3 == string)){end = startlen + conteudo[startlen..$].countUntil(fim);}
	static if (is(T3 == None)) {return conteudo[start];} else {return conteudo[start..end];}
}