Code repetition

[Malte]

On Sunday, 27 May 2018 at 06:47:38 UTC, IntegratedDimensions 
wrote:
> A string mixin is too messy since it treats the code as a 
> string losing all syntax highlighting, etc.
>
> I'd love to have something like a template mixin where I can 
> just do
>
> mixin template fooSetup(ret)
> {
>     // setup stuff
>     int x;
>     scope(exit) something;
>
> }
>
>
> and
>
> void foo()
> {
>    fooSetup(3);
> }
>
>
> void foo4()
> {
>    fooSetup(13);
> }
>
> and everything behave as it should. I'm guessing this is going 
> to be impossible to achieve in D?

Well, if you want to have the same power as Cs textual 
replacement, you need string mixins. Often you can replace it 
with templates, but that depends on the application. I would 
avoid it if you can though, but more for debugging and not 
because of syntax highlighting.

void main()
{
     import std.stdio;

     int y = 1;
     mixin(fooSetup(3));
     writeln("x is ",x);
     x = 5;
}

string fooSetup(int val) {
     import std.conv;

     return q{
         int x = }~val.to!string~q{;
         scope(exit) {
             writeln("x was ", x);
             writeln("y was ", y);
         }
     };
}