Question about @nogc

[monarch_dodra via Digitalmars-d-learn]

On Tuesday, 20 May 2014 at 21:04:37 UTC, anonymous wrote:
> On Tuesday, 20 May 2014 at 20:15:09 UTC, Dominikus Dittes 
> Scherkl
> wrote:
>> /// create a fixed size array with the given name and with 
>> *max* entries
>
> max + 1 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) ~" ]";
>> }
>
> Couldn't resist purging that of the string fiddling:
>
>      ...
>
>      enum ReturnType!fn[length] lookupTable = [elements];

Depending on what the usecase is, you might want to change that 
to static immutable instead:

static immutable ReturnType!fn[length] lookupTable = [elements];

Remember that when using an enum, the compiler will create a 
*new* variable on every use. While the compiler can sometimes 
avoid actually allocating, it may also insert some object code 
bloat to do so.