+ if (lex_token (lexer) != T_ID)
+ {
+ lex_error (lexer, NULL);
+ return false;
+ }
+
+ loop->index_var = dict_lookup_var (dataset_dict (ds), lex_tokid (lexer));
+ if (loop->index_var != NULL)
+ *created_index_var = false;
+ else
+ {
+ loop->index_var = dict_create_var_assert (dataset_dict (ds),
+ lex_tokid (lexer), 0);
+ *created_index_var = true;
+ }
+ lex_get (lexer);
+
+ if (!lex_force_match (lexer, '='))