Merge pull request 'Implement vector swizzling in Kym' (#36) from kym-vector-swizzling into main

Reviewed-on: #36

debug/app.ona

@@ -2,6 +2,7 @@
 # Test comment.
 
 pos = @vec3(10, 20, 0.3)
+coord = pos.xz
 
 options = {
 	.title = "Afterglow",

source/ona/kym.zig

@@ -1088,6 +1088,57 @@ pub const RuntimeEnv = struct {
 
 	pub fn get(self: *RuntimeEnv, indexable: *RuntimeRef, index: *const RuntimeRef) RuntimeError!?*RuntimeRef {
 		return switch (indexable.object().payload) {
+			.vector2 => |vector2| swizzle: {
+				const swizzle_symbol = try self.unbox_symbol(index);
+				var swizzle_buffer = [_]f32{0} ** 3;
+				var swizzle_count = @as(usize, 0);
+
+				while (true) : (swizzle_count += 1) {
+					if (swizzle_count > swizzle_buffer.len) {
+						return null;
+					}
+
+					swizzle_buffer[swizzle_count] = switch (swizzle_symbol[swizzle_count]) {
+						0 => break: swizzle switch (swizzle_count) {
+							1 => self.new_float(swizzle_buffer[0]),
+							2 => self.new_vector2(swizzle_buffer[0], swizzle_buffer[1]),
+							3 => self.new_vector3(swizzle_buffer[0], swizzle_buffer[1], swizzle_buffer[2]),
+							else => unreachable,
+						},
+
+						'x' => vector2[0],
+						'y' => vector2[1],
+						else => return null,
+					};
+				}
+			},
+
+			.vector3 => |vector3| swizzle: {
+				const swizzle_symbol = try self.unbox_symbol(index);
+				var swizzle_buffer = [_]f32{0} ** 3;
+				var swizzle_count = @as(usize, 0);
+
+				while (true) : (swizzle_count += 1) {
+					if (swizzle_count > swizzle_buffer.len) {
+						return null;
+					}
+
+					swizzle_buffer[swizzle_count] = switch (swizzle_symbol[swizzle_count]) {
+						0 => break: swizzle switch (swizzle_count) {
+							1 => self.new_float(swizzle_buffer[0]),
+							2 => self.new_vector2(swizzle_buffer[0], swizzle_buffer[1]),
+							3 => self.new_vector3(swizzle_buffer[0], swizzle_buffer[1], swizzle_buffer[2]),
+							else => unreachable,
+						},
+
+						'x' => vector3[0],
+						'y' => vector3[1],
+						'z' => vector3[2],
+						else => return null,
+					};
+				}
+			},
+
 			.dynamic => |dynamic| dynamic.typeinfo().get(.{
 				.userdata = dynamic.userdata(),
 				.env = self,
@@ -1298,7 +1349,7 @@ pub const RuntimeEnv = struct {
 		};
 	}
 
-	pub fn unbox_symbol(env: *RuntimeEnv, value: *RuntimeRef) RuntimeError![*:0]const coral.io.Byte {
+	pub fn unbox_symbol(env: *RuntimeEnv, value: *const RuntimeRef) RuntimeError![*:0]const coral.io.Byte {
 		return switch (value.object().payload) {
 			.symbol => |symbol| symbol,
 			else => env.raise(error.TypeMismatch, "expected symbol object")