Type helpers instead of UFCS

[John Colvin via Digitalmars-d]

On Saturday, 12 September 2015 at 20:37:37 UTC, BBasile wrote:
> UFCS is good but there are two huge problems:
> - code completion in IDE. It'will never work.
> - noobs, code is unreadable.
>
> That's why I propose the new keywords 'helper' and 'subject' 
> that will allow to extend the properties pre-defined for a 
> type, as long as the helper is imported:
>
> ---
> module myhelper;
> helper for subject : string
> {
>     void writeln()
>     {
>         import std.stdio;
>         writeln(subject);
>     }
> }
> ---
>
> this will allow IDE plugins to provide better completion.
>
> for example if 'Peter' types
>
> ---
> void foo()
> {
>     import myhelper;
>     "foobarbaz".
> }
> ---
>
> after the dot, 'Peter' can get ".writeln".
> Why ? because a clear grammatical construction will allow an 
> IDE plugin to work on a type and provides additional helpers 
> that would be hard to put in the list without any specific 
> grammatical construction.
>
> ...

How is this different to just having a specific type for the 
first argument?

void writeln(Args...)(string s, Args args)
{
     static import std.stdio;
     std.stdio.writeln(s, args);
}