Explicitly use defaults for some parameters in class template instantiation

Question

A class template can have multiple parameters that all have defaults.

template

        

Answer 1

There isn't a way to reuse the default parameters directly. You can use Floris's comment as a way to provide shorthands for common uses, but the template alias will still repeat the defaults.

Alternatively, the options struct could be set up to allow switching out parameters:

template 
struct options {
  template 
  using WithT0 = options;
  template 
  using WithT1 = options;
  template 
  using WithStringT = options;
};

And then use it as

options<>::WithT1::WithStringT