Question about @nogc

[Dominikus Dittes Scherkl via Digitalmars-d-learn]

On Tuesday, 20 May 2014 at 17:14:31 UTC, John Colvin wrote:
> On Tuesday, 20 May 2014 at 12:25:11 UTC, Dominikus Dittes 
> Scherkl wrote:
>> Did I understand correct that a function can only be @nogc if 
>> also all functions that it calls are @nogc too (and of course 
>> it doesn't use the GC itself)?
>>
>> If so, should this be possible:
>>
>> string foo()
>> {
>>   // use GC to allocate some string
>> }
>>
>> bar @nogc
>> {
>>   mixin(foo());
>> }
>>
>> Because, bar() didn't really call foo() but instead foo() is 
>> evaluated during compile time and it's result is now part of 
>> the code, right?
>
> Yes, that should be allowed.

Thanks. This is nice to know, because I will use this a lot in 
the future:

/// create a fixed size array with the given name and with *max* 
entries
/// of immutable values of the same type as the return value of 
the
/// given function.
/// it contains the values of that function in the range [0..max].
string makeLookupTable(alias fn, uint max=255)(string name) pure 
@safe if(is(typeof(fn(max))))
{
    string table = "immutable " ~ to!string(typeof(fn(max))) ~ "[" 
~ to!string(max+1) ~ "] " ~ name ~"= [ ";
    foreach(i; 0..max) table ~= to!string(fn(i) ~ ", ";
    return table ~ to!string(fn(max) ~" ]";
}