ecs: simplify how modules are written
Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst
Stephen Gutekanst
parent
85ffb37156
commit
4575080ca9
2 changed files with 64 additions and 80 deletions
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@ -21,7 +21,6 @@ pub const Modules = @import("systems.zig").Modules;
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pub const Messages = @import("systems.zig").Messages;
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pub const MessagesTag = @import("systems.zig").MessagesTag;
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pub const World = @import("systems.zig").World;
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pub const View = @import("systems.zig").View;
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// TODO:
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// * Iteration
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@ -37,33 +36,34 @@ test "inclusion" {
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test "example" {
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const allocator = testing.allocator;
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const PhysicsMsg = Messages(.{
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.tick = void,
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});
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const physicsUpdate = (struct {
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pub fn physicsUpdate(msg: PhysicsMsg) void {
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const Physics2D = Module(struct {
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pointer: u8,
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pub const name = .physics;
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pub const components = .{
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.id = u32,
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};
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pub const Message = .{
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.tick = void,
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};
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pub fn update(msg: Message) void {
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switch (msg) {
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.tick => std.debug.print("\nphysics tick!\n", .{}),
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}
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}
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}).physicsUpdate;
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});
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const Renderer = Module(struct {
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pub const name = .renderer;
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pub const components = .{
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.id = u16,
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};
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});
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const modules = Modules(.{
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.physics = Module(.{
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.components = .{
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.id = u32,
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},
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.globals = struct {
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pointer: u8,
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},
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.messages = PhysicsMsg,
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.update = physicsUpdate,
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}),
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.renderer = Module(.{
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.components = .{
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.id = u16,
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},
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}),
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Physics2D,
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Renderer,
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});
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//-------------------------------------------------------------------------
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@ -9,15 +9,25 @@ const UnionField = std.builtin.Type.UnionField;
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const Entities = @import("entities.zig").Entities;
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/// An ECS module can provide components, systems, and global values.
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pub fn Module(comptime Params: anytype) @TypeOf(Params) {
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// TODO: validate the type
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return Params;
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/// Validates that a module matches the expected type layout.
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///
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/// An ECS module has components, systems, global values & more.
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pub fn Module(comptime M: anytype) type {
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if (@hasDecl(M, "name")) {
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_ = @tagName(M.name);
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} else @compileError("Module missing `pub const name = .foobar;`");
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if (@hasDecl(M, "Message")) _ = Messages(M.Message);
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// TODO(ecs): validate M.components decl signature, if present.
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// TODO(ecs): validate M.update method signature, if present.
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return M;
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}
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/// Describes a set of ECS modules, each of which can provide components, systems, and more.
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/// Validates that a list of module matches the expected type layout.
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///
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/// ECS modules have components, systems, global values & more.
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pub fn Modules(comptime modules: anytype) @TypeOf(modules) {
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// TODO: validate the type
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inline for (modules) |m| _ = Module(m);
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return modules;
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}
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@ -95,9 +105,10 @@ fn NamespacedComponents(comptime modules: anytype) type {
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var fields: []const StructField = &[0]StructField{};
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inline for (std.meta.fields(@TypeOf(modules))) |module_field| {
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const module = @field(modules, module_field.name);
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if (@hasField(@TypeOf(module), "components")) {
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const module_name = @tagName(@field(module, "name"));
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if (@hasDecl(module, "components")) {
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fields = fields ++ [_]std.builtin.Type.StructField{.{
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.name = module_field.name,
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.name = module_name,
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.type = @TypeOf(module.components),
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.default_value = null,
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.is_comptime = false,
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@ -115,28 +126,9 @@ fn NamespacedComponents(comptime modules: anytype) type {
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});
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}
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/// Extracts namespaces components from modules like this:
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///
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/// ```
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/// .{
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/// .renderer = .{
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/// .components = .{
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/// .location = Vec3,
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/// .rotation = Vec3,
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/// },
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/// ...
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/// },
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/// .physics2d = .{
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/// .components = .{
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/// .location = Vec2
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/// .velocity = Vec2,
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/// },
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/// ...
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/// },
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/// }
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/// ```
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///
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/// Returning a namespaced components value like this:
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/// Extracts namespaces components from modules like this. A module is said to have components if
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/// the struct has a `pub const components`. This function returns a namespaced components value
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/// like e.g.:
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///
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/// ```
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/// .{
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@ -155,34 +147,16 @@ fn namespacedComponents(comptime modules: anytype) NamespacedComponents(modules)
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var x: NamespacedComponents(modules) = undefined;
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inline for (std.meta.fields(@TypeOf(modules))) |module_field| {
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const module = @field(modules, module_field.name);
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if (@hasField(@TypeOf(module), "components")) {
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@field(x, module_field.name) = module.components;
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const module_name = @tagName(@field(module, "name"));
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if (@hasDecl(module, "components")) {
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@field(x, module_name) = module.components;
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}
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}
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return x;
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}
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/// Extracts namespaced globals from modules like this:
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///
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/// ```
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/// .{
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/// .renderer = .{
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/// .globals = struct{
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/// foo: *Bar,
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/// baz: Bam,
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/// },
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/// ...
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/// },
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/// .physics2d = .{
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/// .globals = struct{
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/// foo: *Instance,
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/// },
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/// ...
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/// },
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/// }
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/// ```
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///
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/// Into a namespaced global type like this:
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/// Extracts namespaced globals from modules (a module is said to have globals if the struct has
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/// any fields), returning a type like e.g.:
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///
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/// ```
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/// struct{
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@ -200,13 +174,23 @@ fn NamespacedGlobals(comptime modules: anytype) type {
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var fields: []const StructField = &[0]StructField{};
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inline for (std.meta.fields(@TypeOf(modules))) |module_field| {
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const module = @field(modules, module_field.name);
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if (@hasField(@TypeOf(module), "globals")) {
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const module_name = @tagName(@field(module, "name"));
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const global_fields = std.meta.fields(module);
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if (global_fields.len > 0) {
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const Globals = @Type(.{
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.Struct = .{
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.layout = .Auto,
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.is_tuple = false,
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.fields = global_fields,
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.decls = &[_]std.builtin.Type.Declaration{},
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},
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});
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fields = fields ++ [_]std.builtin.Type.StructField{.{
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.name = module_field.name,
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.type = module.globals,
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.name = module_name,
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.type = Globals,
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.default_value = null,
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.is_comptime = false,
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.alignment = @alignOf(module.globals),
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.alignment = @alignOf(Globals),
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}};
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}
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}
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@ -272,7 +256,7 @@ pub fn World(comptime modules: anytype) type {
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pub fn send(world: *Self, comptime msg_tag: anytype) !void {
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inline for (std.meta.fields(@TypeOf(modules))) |module_field| {
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const module = @field(modules, module_field.name);
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if (@hasField(@TypeOf(module), "messages")) {
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if (@hasDecl(module, "messages")) {
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if (@hasField(module.messages, @tagName(msg_tag))) try module.update(world, msg_tag);
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}
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}
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