lang: ast: define ast_node_type for some fundamental expression components

lang/ast/msg.c

@@ -0,0 +1,28 @@
+#include "ctx.h"
+#include "node.h"
+
+static void collect_children(
+	struct ivy_ast_node *node, struct ivy_ast_node_iterator *iterator)
+{
+	struct ivy_ast_msg_node *msg = (struct ivy_ast_msg_node *)node;
+
+	if (msg->n_recipient) {
+		ast_node_iterator_enqueue_node(iterator, node, msg->n_recipient);
+	}
+
+	if (msg->n_sel) {
+		ast_node_iterator_enqueue_node(iterator, node, msg->n_sel);
+	}
+
+	b_queue_iterator it = {0};
+	b_queue_foreach (&it, &msg->n_arg) {
+		struct ivy_ast_node *arg = b_unbox(struct ivy_ast_node, it.entry, n_entry);
+		ast_node_iterator_enqueue_node(iterator, node, arg);
+	}
+}
+
+struct ast_node_type msg_node_ops = {
+	.n_collect_children = collect_children,
+        .n_state_size = sizeof(struct parser_state),
+        .n_node_size = sizeof(struct ivy_ast_msg_node),
+};