On Sunday, 19 September 2021 at 03:58:41 UTC, Kirill wrote:
How can I get the base type of any
(multidimensional/static/dynamic/associative) array?
Example:
```
void main() {
int[][] intArr;
double[4][] doubleArr;
string[string][] strArr;
intArr.example; // T = int
doubleArr.example; // T = double
strArr.example; // T = string
}
void example(T)(<...> data) {
// extract the base of data (inside func's body or in <...>)
// preferably, T must become data's base type
}
```
This almost works, but as `string` is an array type it needs some
kind of rule to stop there:
```d
unittest {
int[] intArr;
double[4][] doubleArr;
string[string][][] strArr;
assert(is(BaseType!(typeof(intArr)) == int));
assert(is(BaseType!(typeof(doubleArr)) == double));
assert(is(BaseType!(typeof(strArr)) == immutable(char)));
}
template BaseType(T) {
static if (__traits(isStaticArray, T))
alias BaseType = BaseType!(typeof(T.init[0]));
else static if (is(T == U[], U))
alias BaseType = BaseType!U;
else static if (is(T == V[K], K, V))
alias BaseType = BaseType!V;
else
alias BaseType = T;
}
```
mix of BaseType!T from core.internal.array.equality and rank!T
from Philippe Sigaud's D Templates Tutorial at
https://github.com/PhilippeSigaud/D-templates-tutorial
