Global variables read at compile time?

[RommelVR]

On Wednesday, 15 August 2012 at 13:36:26 UTC, Stefan wrote:
> Hi there, I'm having trouble getting the following code to 
> compile:
>
> import std.stdio;
>
> string a = "a";
> string b = a;
>
> void main()
> {
>     writeln(b);
> }
>
> DMD spits out the error "test.d(4): Error: variable a cannot be 
> read at compile time". Is there any way to tell the compiler I 
> want b evaluated at runtime, or am I missing something obvious 
> here?

Make a an enum, const or otherwise immutable.