On Monday, 5 February 2024 at 21:12:58 UTC, Gary Chike wrote:
[ ... ]
In addition to the methods hitherto provided:
```d
auto getUser() => tuple("John Doe", 32);
// Name a Tuple's fields post hoc by copying the original's
fields into a new Tuple.
template named(names...) {
auto named(T)(ref auto T t) if (names.length <=
T.Types.length) =>
tuple!names(t.expand[0..names.length]);
}
{
auto u = getUser().named!("name", "age");
writeln(u.name, " (", u.age, ")"); // John Doe (32)
// You could also do this. If only `with` were an expression!
with (getUser().named!("name", "age"))
writeln(name, " (", age, ")"); // John Doe (32)
}
// Define variables corresponding to a Tuple's fields in the
current scope, whose
// identifiers are given by `names`.
mixin template Unpack(alias t, names...)
if (names.length <= t.Types.length) {
static foreach (i, n; names)
mixin("auto ", n, " = t[i];");
}
{
auto u = getUser();
mixin Unpack!(u, "name", "age");
writeln(name, " (", age, ")"); // John Doe (32)
}
```
For either of these, one can "unpack" some or none of a Tuple's
fields, and both can be modified to ignore any field to simulate
`val (name, _, prof) = ("John Doe", 32, "Chemist")`.
