Talk:DIP32

About $identifier

Why not require normal declaration syntax, when a variable should be declared in unpacking?

Suggested in DIP:

switch (tup) {
    case {1, 2}:
    case {$, 2}:
    case {1, x}:
    default:
}
// -----------------------------
int x = 1;
if (auto {$x, y} = coord) { ... }

My suggestion:

switch (tup) {
    case {1, 2}:
    case {$, 2}:
    case {1, auto x}:
    default:
}
// -----------------------------
int x = 1;
if ({x, auto y} = coord) { ... }

This would be more consistent with how if usually works (expression syntax => use existing variable, declaration syntax => declare variable initialized with the value of the comparison), doesn't require this special syntax which is used nowhere else in the language, and makes it obvious that a declaration takes place.

It also allows to use unpacking everywhere:

int x;
{x, int y} = tup;

Variable declaration in case statements

Care must be taken when variable declaration is used in combination with fall through / goto case in case statements:

switch (tup) {
    case {1, 2}:
    case {$, 2}:
        goto case;
    case {1, x}:
        // what is x if tup == {1, 2}?
}

Tuple Slicing?

If you want you can also add a slicing syntax for tuples:

auto t1 = {10, 20.5, "foo"};
auto t2 = t1[1 .. $];