Add lookupSymbol, lookupChild, rename lookupPath

src/world.zig

@@ -59,13 +59,32 @@ pub fn World(comptime ctx: anytype) type {
             return result;
         }
 
+        /// Returns the `Entity` with the specified unique symbol, or null if none.
+        pub fn lookupSymbol(self: *Self, symbol: []const u8) ?Entity {
+            const result = c.ecs_lookup_symbol(self.raw, symbol.ptr, false, false);
+            return if (result != 0) Entity.fromRaw(self, result) else null;
+        }
+
+        /// Returns the `Entity` with the specified parent and name, or null if none.
+        /// If no parent is specified, the world root is used instead.
+        pub fn lookupChild(self: *Self, parent: anytype, name: []const u8) ?Entity {
+            var name_buffer: [256]u8 = undefined;
+            if (name.len + 1 > name_buffer.len) @panic("Name too long");
+            @memcpy(name_buffer[0..name.len], name);
+            name_buffer[name.len] = 0;
+
+            const parent_ = Context.anyToEntity(parent);
+            const result = c.ecs_lookup_child(self.raw, parent_, &name_buffer);
+            return if (result != 0) Entity.fromRaw(self, result) else null;
+        }
+
         // TODO: Reconsider whether lookup functions should return errors or just optionals.
         // TODO: Reconsider whether "Entity" should always be in backticks in our doc comments.
         // TODO: We really need tests for this function.
         /// Returns the `Entity` at the specified path, or an error if the
         /// entity does not exist. If the path is not absolute, the operation
         /// will use the current scope, or the world root.
-        pub fn lookupByPath(self: *Self, path: Path) !Entity {
+        pub fn lookupPath(self: *Self, path: Path) !Entity {
             var parent = if (path.absolute) 0 else c.ecs_get_scope(self.raw);
             var current: c.ecs_entity_t = undefined;
             for (path.parts) |part| {