Duck typing and safety.

[Mafi]

Am 13.08.2010 19:01, schrieb simendsjo:
> import std.stdio;
>
> struct S
> {
>      void shittyNameThatProbablyGetsRefactored() { };
> }
>
> void process(T)(T s)
> {
>      static if( __traits(hasMember, T,
> "shittyNameThatProbablyGetsRefactored"))
>      {
>          writeln("normal processing");
>      }
>      else
>      {
>          writeln("Start nuclear war!");
>      }
> }
>
>
> void main()
> {
>      S s;
>      process(s);
> }
>
>
> If you rename S's method, process() does something completely different
> without a compile time error. By using interfaces this is avoided as the
> rename would break the interface.
As I understand this, you want t never start a nuclear war (lol) so do 
something like this:

void process(T)(T s) if ( __traits(hasMember, T, 
"shittyNameThatProbablyGetsRefactored")) {...}

The if here is a template constraint, which is part of the signature 
(which means you can overload with those). If you try to instantiate 
your template in a wrong manner, you get a nice ct error at the 
instantiation.

Then you can remove the unreachable 'war'-branch.

Mafi