a67627a691
Calling a protocol method on a pack element now works: `xs[i].greet()` on a `..xs: Greeter` pack dispatches to the concrete element's impl, and elements may be heterogeneous (Dog, Cat). This is the protocol-interface access the pack is for. (Protocol method decls omit the implicit `self`; impls list it — the earlier malformed `(self: *Self)` decls were why dispatch looked broken.) Also fixes packArgConformsTo for non-parameterised protocols: it queried `protocol_thunk_map`, which is only populated lazily when a protocol VALUE is built with `xx`, so it false-negatived valid conformers. Now it queries impl-declaration state directly — `param_impl_map` for parameterised protocols, or `<ty>.<method>` entries in `fn_ast_map` for non-parameterised ones. examples/193-protocol-pack-methods.sx (heterogeneous Dog+Cat pack, per-element greet(), order-independent).
32 lines
1.1 KiB
Plaintext
32 lines
1.1 KiB
Plaintext
// Feature 1 — protocol-interface method calls on heterogeneous pack elements.
|
|
//
|
|
// `..xs: Greeter` binds per call shape; each `xs[i]` is the concrete element,
|
|
// and calling the protocol's own method `greet()` on it dispatches to that
|
|
// element's impl. Elements may be DIFFERENT concrete types (Dog, Cat) as long
|
|
// as each conforms to Greeter — this is the protocol-interface access the
|
|
// pack is for. (Protocol method decls omit the implicit `self`; impls list it.)
|
|
|
|
#import "modules/std.sx";
|
|
|
|
Greeter :: protocol {
|
|
greet :: () -> s64;
|
|
}
|
|
|
|
Dog :: struct { age: s64; }
|
|
Cat :: struct { lives: s64; }
|
|
impl Greeter for Dog { greet :: (self: *Dog) -> s64 => self.age; }
|
|
impl Greeter for Cat { greet :: (self: *Cat) -> s64 => self.lives * 100; }
|
|
|
|
pair_sum :: (..xs: Greeter) -> s64 {
|
|
return xs[0].greet() + xs[1].greet();
|
|
}
|
|
|
|
main :: () -> s32 {
|
|
d := Dog.{ age = 3 };
|
|
c := Cat.{ lives = 9 };
|
|
print("dog+cat={}\n", pair_sum(d, c)); // 3 + 900 = 903 (heterogeneous)
|
|
print("cat+dog={}\n", pair_sum(c, d)); // 900 + 3 = 903 (order swapped)
|
|
print("dog+dog={}\n", pair_sum(d, Dog.{ age = 4 })); // 3 + 4 = 7
|
|
0;
|
|
}
|