Question on Template Specializing.

[evilrat]

On Wednesday, 7 August 2013 at 05:10:25 UTC, SteveGuo wrote:
> But my question is:
> If I am a library author, I write templates for my users, so 
> users can specialize the template with any types they defined. 
> I don't know what types they may define when I design the 
> template, so how can I specialize the template for them in my 
> template module?

if you want to make some presets for common types you can use 
aliases

alias A!int Aint;
alias A!float Afloat;
...

if you want to enforce template accept only certain types you 
should use static asserts or type covariance(oh sorry it's not 
called this but i'm somehow stupid now)

-------------
// type limitation with overloading
interface Something { ... }

// specialized template for covariants of Something(will be 
instantiated with any covariant of Something)
class A(T: Something) {
...
}

// generic template(instantiated when no specialized overloads 
exists)
class A(T) {

}
-------------
or static asserts/if
-------------
import std.traits;
class A(T) {
  // code for numeric types
  static if(isNumeric(T)) {
  ...
  }

  // code for callable objects
  static if(isCallable(T)) {

  }

  // and so on...
}