Templates args

[Lodovico Giaretta via Digitalmars-d-learn]

On Thursday, 14 July 2016 at 19:28:23 UTC, Andrey wrote:
> On Thursday, 14 July 2016 at 19:27:14 UTC, Andrey wrote:
>> Hi guys!
>>
>> Help a newbie please.
>>
>> Playing with D and trying to understand some features.
>> Here is my try to carry out my code from C++ project to D
>>
>> struct Sigmoid(T)
>> {
>>   const T Function(T value)
>>   {
>>    ...
>>   }
>>   const T DerivateFunction(const T value)
>>   {
>>    ...
>>   }
>> }
>>
>> struct Neurons_layer(T = float, size_t neurons_num = 0, F = 
>> Sigmoid!T)
>>   if(isFloatingPoint!T && is(typeof(F.Function)))
>>     {
>>     private:
>>       static if(neurons_num > 0)
>> 	T[neurons_num] _neurons_arr;
>>       else
>> 	T[] _neurons_arr;
>>
>>     private:
>>       alias Function = F.Function;
>> }
>>
>> unittest
>> {
>>   Neurons_layer!(float,5,Sigmoid!float) nf;
>> }
>>
>>
>> The question is - How to make in pretty way this line:
>>  Neurons_layer!(float,5,Sigmoid!float) nf;
>
> to something like - Neurons_layer!(float,5,Sigmoid) nf;

You don't need Sigmoid!float at all. This will work:

Neurons_layer!(float, 5) nf;

as you provided a default value for the third argument.