@@ 504,6 504,123 @@ return (struct mrsh_binop *)and_or_list;
  }
  
+ static void node_array_for_each(struct mrsh_array *nodes,
+ 		mrsh_node_iterator_func iterator, void *user_data) {
+ 	for (size_t i = 0; i < nodes->len; ++i) {
+ 		struct mrsh_node *node = nodes->data[i];
+ 		mrsh_node_for_each(node, iterator, user_data);
+ 	}
+ }
+ 
+ void mrsh_node_for_each(struct mrsh_node *node,
+ 		mrsh_node_iterator_func iterator, void *user_data) {
+ 	iterator(node, user_data);
+ 
+ 	switch (node->type) {
+ 	case MRSH_NODE_PROGRAM:;
+ 		struct mrsh_program *program = mrsh_node_get_program(node);
+ 		node_array_for_each(&program->body, iterator, user_data);
+ 		return;
+ 	case MRSH_NODE_COMMAND_LIST:;
+ 		struct mrsh_command_list *list = mrsh_node_get_command_list(node);
+ 		mrsh_node_for_each(&list->and_or_list->node, iterator, user_data);
+ 		return;
+ 	case MRSH_NODE_AND_OR_LIST:;
+ 		struct mrsh_and_or_list *and_or_list = mrsh_node_get_and_or_list(node);
+ 		switch (and_or_list->type) {
+ 		case MRSH_AND_OR_LIST_BINOP:;
+ 			struct mrsh_binop *binop = mrsh_and_or_list_get_binop(and_or_list);
+ 			mrsh_node_for_each(&binop->left->node, iterator, user_data);
+ 			mrsh_node_for_each(&binop->right->node, iterator, user_data);
+ 			return;
+ 		case MRSH_AND_OR_LIST_PIPELINE:;
+ 			struct mrsh_pipeline *pipeline =
+ 				mrsh_and_or_list_get_pipeline(and_or_list);
+ 			node_array_for_each(&pipeline->commands, iterator, user_data);
+ 			return;
+ 		}
+ 		assert(false);
+ 	case MRSH_NODE_COMMAND:;
+ 		struct mrsh_command *cmd = mrsh_node_get_command(node);
+ 		switch (cmd->type) {
+ 		case MRSH_SIMPLE_COMMAND:;
+ 			struct mrsh_simple_command *sc =
+ 				mrsh_command_get_simple_command(cmd);
+ 			if (sc->name != NULL) {
+ 				mrsh_node_for_each(&sc->name->node, iterator, user_data);
+ 			}
+ 			node_array_for_each(&sc->arguments, iterator, user_data);
+ 			// TODO: io_redirects, assignments
+ 			return;
+ 		case MRSH_BRACE_GROUP:;
+ 			struct mrsh_brace_group *bg = mrsh_command_get_brace_group(cmd);
+ 			node_array_for_each(&bg->body, iterator, user_data);
+ 			return;
+ 		case MRSH_SUBSHELL:;
+ 			struct mrsh_subshell *ss = mrsh_command_get_subshell(cmd);
+ 			node_array_for_each(&ss->body, iterator, user_data);
+ 			return;
+ 		case MRSH_IF_CLAUSE:;
+ 			struct mrsh_if_clause *ic = mrsh_command_get_if_clause(cmd);
+ 			node_array_for_each(&ic->condition, iterator, user_data);
+ 			node_array_for_each(&ic->body, iterator, user_data);
+ 			if (ic->else_part != NULL) {
+ 				mrsh_node_for_each(&ic->else_part->node, iterator, user_data);
+ 			}
+ 			return;
+ 		case MRSH_FOR_CLAUSE:;
+ 			struct mrsh_for_clause *fc = mrsh_command_get_for_clause(cmd);
+ 			node_array_for_each(&fc->word_list, iterator, user_data);
+ 			node_array_for_each(&fc->body, iterator, user_data);
+ 			return;
+ 		case MRSH_LOOP_CLAUSE:;
+ 			struct mrsh_loop_clause *lc = mrsh_command_get_loop_clause(cmd);
+ 			node_array_for_each(&lc->condition, iterator, user_data);
+ 			node_array_for_each(&lc->body, iterator, user_data);
+ 			return;
+ 		case MRSH_CASE_CLAUSE:;
+ 			struct mrsh_case_clause *cc = mrsh_command_get_case_clause(cmd);
+ 			mrsh_node_for_each(&cc->word->node, iterator, user_data);
+ 			// TODO: items
+ 			return;
+ 		case MRSH_FUNCTION_DEFINITION:;
+ 			struct mrsh_function_definition *fn =
+ 				mrsh_command_get_function_definition(cmd);
+ 			mrsh_node_for_each(&fn->body->node, iterator, user_data);
+ 			return;
+ 		}
+ 		assert(false);
+ 	case MRSH_NODE_WORD:;
+ 		struct mrsh_word *word = mrsh_node_get_word(node);
+ 		switch (word->type) {
+ 		case MRSH_WORD_STRING:
+ 			return;
+ 		case MRSH_WORD_PARAMETER:;
+ 			struct mrsh_word_parameter *wp = mrsh_word_get_parameter(word);
+ 			if (wp->arg != NULL) {
+ 				mrsh_node_for_each(&wp->arg->node, iterator, user_data);
+ 			}
+ 			return;
+ 		case MRSH_WORD_COMMAND:;
+ 			struct mrsh_word_command *wc =	mrsh_word_get_command(word);
+ 			if (wc->program != NULL) {
+ 				mrsh_node_for_each(&wc->program->node, iterator, user_data);
+ 			}
+ 			return;
+ 		case MRSH_WORD_ARITHMETIC:;
+ 			struct mrsh_word_arithmetic *wa = mrsh_word_get_arithmetic(word);
+ 			mrsh_node_for_each(&wa->body->node, iterator, user_data);
+ 			return;
+ 		case MRSH_WORD_LIST:;
+ 			struct mrsh_word_list *wl = mrsh_word_get_list(word);
+ 			node_array_for_each(&wl->children, iterator, user_data);
+ 			return;
+ 		}
+ 		assert(false);
+ 	}
+ 	assert(false);
+ }
+ 
  static void position_next(struct mrsh_position *dst,
  		const struct mrsh_position *src) {
  	*dst = *src;

@@ 399,6 399,9 @@ struct mrsh_array body; // struct mrsh_command_list *
  };
  
+ typedef void (*mrsh_node_iterator_func)(struct mrsh_node *node,
+ 	void *user_data);
+ 
  bool mrsh_position_valid(const struct mrsh_position *pos);
  bool mrsh_range_valid(const struct mrsh_range *range);
  


@@ 478,6 481,9 @@ struct mrsh_binop *mrsh_and_or_list_get_binop(
  	const struct mrsh_and_or_list *and_or_list);
  
+ void mrsh_node_for_each(struct mrsh_node *node,
+ 	mrsh_node_iterator_func iterator, void *user_data);
+ 
  void mrsh_word_range(struct mrsh_word *word, struct mrsh_position *begin,
  	struct mrsh_position *end);
  void mrsh_command_range(struct mrsh_command *cmd, struct mrsh_position *begin,