static foreach considered

[jmh530 via Digitalmars-d]

On Monday, 8 June 2015 at 20:02:11 UTC, Andrei Alexandrescu wrote:
> I'm trying to collect together motivating examples and to 
> figure out the semantics of the feature.


I was just playing around with something and I thought being able 
to do a loop over an enum at compile time would be convenient. 
The motivation is when you have a function that works a little 
differently for arrays than for scalers, but it works the same 
way for all sizes of arrays (i.e. 1d/2d/3d all the same).

template GenArrayMathFunction(string function_name, string 
array_string)
{
const char[] GenArrayMathFunction =
	"real" ~ array_string ~ " " ~ function_name ~"(real" ~ 
array_string ~ " x) {\n" ~
	"\treal" ~ array_string ~" result = x.map!(a => " ~ 
function_name ~ "(a)).array;\n" ~
	"\treturn result;\n" ~
	"}";
}

private enum array_dimension
{
	Dim1 = "[]",
	Dim2 = "[][]",
	Dim3 = "[][][]"
}

static foreach(i; array_dimension)
{
	mixin(GenArrayMathFunction!(f, i));
}

Basically, the first part generates a string representing a 
function that uses map to apply a function to some input. The 
type of the input depends on a string representing the kind of 
array. The enum represents a string for 1/2/3-dimensional arrays. 
Finally, I would want to loop through the enums and use mixin to 
create a function for each.

The foreach loop doesn't work right now. Right now, I've just 
written out each of the three functions and put in 
array_dimension.Dim1, etc.