get_switch_expr
if (!get_switch_expr())
switch_expr = get_switch_expr();
if (get_switch_expr() == last_print_expr)
last_print_expr = get_switch_expr();
if (!get_switch_expr())
set_state_expr(my_id, left, alloc_my_state(get_switch_expr()));
struct expression *get_switch_expr(void);