Last version for now, it can be improved further in various ways:
import std.typetuple: TypeTuple;
import std.metastrings: Format;
template Iota(int stop) {
static if (stop <= 0)
alias TypeTuple!() Iota;
else
alias TypeTuple!(Iota!(stop-1), stop-1) Iota;
}
enum string[] str_types = ["int", "float", "short"];
mixin(Format!("alias TypeTuple!(%s, %s, %s) types;", str_types[0],
str_types[1], str_types[2]));
static assert(str_types.length == types.length); // safety
enum string[] str_sizes = ["100", "200", "250"];
mixin(Format!("enum int[] sizes = [%s, %s, %s];", str_sizes[0], str_sizes[1],
str_sizes[2]));
static assert(str_sizes.length == sizes.length); // safety
void staticDispatch3(alias templ)(string run_t, string run_n, string run_m) {
foreach (t; Iota!(str_types.length))
foreach (n; Iota!(str_sizes.length))
foreach (m; Iota!(str_sizes.length))
if (run_t == str_types[t] && run_n == str_sizes[n] && run_m ==
str_sizes[m]) {
templ!(types[t], sizes[n], sizes[m])();
goto END;
}
assert(0); // safety
END: {}
}
// ----------------------------
import std.stdio: writeln;
void foo(T, int N, int M)() {
writeln(typeid(T), " ", N, " ", M);
}
void main() {
staticDispatch3!(foo)("int", "200", "100");
}
A more generic staticDispatch3 like this doesn't work because items1 is a
tuple, so it gets flattened...
void staticDispatch3(alias func, alias str_items1, alias items1,
alias str_items2, alias items2,
alias str_items3, alias items3)
(string run_i1, string run_i2, string run_i3) {
static assert(str_items1.length == items1.length);
static assert(str_items2.length == items2.length);
static assert(str_items3.length == items3.length);
foreach (i1; Iota!(items1.length))
foreach (i2; Iota!(items2.length))
foreach (i3; Iota!(items3.length))
if (run_i1 == str_types[i1] &&
run_i2 == str_types[i2] &&
run_i3 == str_types[i3]) {
func!(items1[i1], items2[i2], items3[i3])();
goto END;
}
assert(0); // safety
END: {}
}
Bye,
bearophile
