This constant in a module causes a compilation error of the "non-constant expression" variety.

DEFINITION 1
  const(AssetProjectionMap) SavingsGrowth2013 = [
    AssetReturnType.Interest :
    RateCurve([DateRate(Date.min, CcRate(0.007))]),
  ];

The fix that addresses this error at module level is:

DEFINITION 2

const(AssetProjectionMap) SavingsGrowth2013;
static this() {
  SavingsGrowth2013 = [
    AssetReturnType.Interest :
    RateCurve([DateRate(Date.min, CcRate(0.007))]),
  ];
}


However, the same constant, when defined in a unittest block works with DEFINITION 1. What is the reason for the difference between unittest constants and module constants?

Thanks,
Dan

On Friday, 8 February 2013 at 20:12:41 UTC, Dan wrote:
> This constant in a module causes a compilation error of the "non-constant expression" variety.
>
> DEFINITION 1
>   const(AssetProjectionMap) SavingsGrowth2013 = [
>     AssetReturnType.Interest :
>     RateCurve([DateRate(Date.min, CcRate(0.007))]),
>   ];
>
> The fix that addresses this error at module level is:
>
> DEFINITION 2
>
> const(AssetProjectionMap) SavingsGrowth2013;
> static this() {
>   SavingsGrowth2013 = [
>     AssetReturnType.Interest :
>     RateCurve([DateRate(Date.min, CcRate(0.007))]),
>   ];
> }
>
>
> However, the same constant, when defined in a unittest block works with DEFINITION 1. What is the reason for the difference between unittest constants and module constants?
>
> Thanks,
> Dan

unittest blocks are evaluated at run time, just like your DEFINITION 2, and unlike your DEFINITION 1 which would be evaluated at compile time.

Yesterday I solved similar problem by using enum.
enum GameInfo[string] games=[
...
];
Dňa 8. 2. 2013 21:21 anonymous  wrote / napísal(a):
> On Friday, 8 February 2013 at 20:12:41 UTC, Dan wrote:
>> This constant in a module causes a compilation error of the
>> "non-constant expression" variety.
>>
>> DEFINITION 1
>>   const(AssetProjectionMap) SavingsGrowth2013 = [
>>     AssetReturnType.Interest :
>>     RateCurve([DateRate(Date.min, CcRate(0.007))]),
>>   ];
>>
>> The fix that addresses this error at module level is:
>>
>> DEFINITION 2
>>
>> const(AssetProjectionMap) SavingsGrowth2013;
>> static this() {
>>   SavingsGrowth2013 = [
>>     AssetReturnType.Interest :
>>     RateCurve([DateRate(Date.min, CcRate(0.007))]),
>>   ];
>> }
>>
>>
>> However, the same constant, when defined in a unittest block works
>> with DEFINITION 1. What is the reason for the difference between
>> unittest constants and module constants?
>>
>> Thanks,
>> Dan
>
> unittest blocks are evaluated at run time, just like your DEFINITION 2,
> and unlike your DEFINITION 1 which would be evaluated at compile time.

On 02/18/2013 08:59 AM, Lubos Pintes wrote:
> Yesterday I solved similar problem by using enum.
> enum GameInfo[string] games=[
> ...
> ];

Be careful with that though: 'games' is a literal associative array, meaning that it will be used in the program as if it's copy-pasted in that location. It looks like there is a single associative array, but there is a new temporary created every time you use 'games':

struct GameInfo
{
    int i;
}

enum GameInfo[string] games = [ "one" : GameInfo(1) ];

void main()
{
    assert(&(games["one"]) != &(games["one"]));    // note: !=
}

As the two games are different, their elements are not at the same location.

This is one way to go:

struct GameInfo
{
    int i;
}

static immutable GameInfo[string] games;

static this()
{
    games = [ "one" : GameInfo(1) ];
}

void main()
{
    assert(&(games["one"]) == &(games["one"]));    // note ==
}

This time there is just one 'games'.

Ali

Thank for explanation. I supposed that the enum constant is fixed and that it is also true for AA.
I will convert my code before I forget. :-).
Dňa 18. 2. 2013 18:22 Ali Çehreli  wrote / napísal(a):
> On 02/18/2013 08:59 AM, Lubos Pintes wrote:
>  > Yesterday I solved similar problem by using enum.
>  > enum GameInfo[string] games=[
>  > ...
>  > ];
>
> Be careful with that though: 'games' is a literal associative array,
> meaning that it will be used in the program as if it's copy-pasted in
> that location. It looks like there is a single associative array, but
> there is a new temporary created every time you use 'games':
>
> struct GameInfo
> {
>      int i;
> }
>
> enum GameInfo[string] games = [ "one" : GameInfo(1) ];
>
> void main()
> {
>      assert(&(games["one"]) != &(games["one"]));    // note: !=
> }
>
> As the two games are different, their elements are not at the same
> location.
>
> This is one way to go:
>
> struct GameInfo
> {
>      int i;
> }
>
> static immutable GameInfo[string] games;
>
> static this()
> {
>      games = [ "one" : GameInfo(1) ];
> }
>
> void main()
> {
>      assert(&(games["one"]) == &(games["one"]));    // note ==
> }
>
> This time there is just one 'games'.
>
> Ali
>

On 02/18/2013 09:22 AM, Ali Çehreli wrote:

> static immutable GameInfo[string] games;
>
> static this()
> {
> games = [ "one" : GameInfo(1) ];
> }

And to be honest, I am not sure why I define it as 'static immutable'. :) Isn't this the same thing?

immutable GameInfo[string] games;

static this()
{
    games = [ "one" : GameInfo(1) ];
}

Ali