Passing macros from commandline or enumerating versions

[Adam D. Ruppe via Digitalmars-d-learn]

The way I like to do it is to pass a module on the command line 
that contains the custom config. So in the app:

---
import myapp.config;

// use the variables defined in there like normal
---


Now, to define a config file, you do something like:


myconfiguration.d # note that the file name can be anything!
---
module myapp.config; // but each must use this same module config

enum some_key = "some_value";
// and so on
---

Now, when you compile, you build it with a particular config by 
passing one of those files to the compile:

dmd myapp.d myconfiguration.d # or whatever single config you want



Then you can define as much as you want in the config module, and 
have as many of them as you want too.