Why does Reggae use mixins?

[Nordlöw via Digitalmars-d-learn]

On Friday, 15 April 2016 at 13:18:46 UTC, Nordlöw wrote:
> Why does the build system Reggae use mixins everywhere in the D 
> examples?
>
> https://github.com/atilaneves/reggae

Correction, it can do stuff either at CT or run-time as show here:

https://github.com/atilaneves/reggae/blob/master/doc/basics.md

Could somebody highlight when either is adviced?