def f_int(self, node): return vm.ValueInt(node.val)
def s_sub_int(a): return vm.ValueInt(-a.val)
def s_add_int_int(a, b): return vm.ValueInt(a.val + b.val)
def s_div_int_int(a, b): return vm.ValueInt(a.val / b.val)
def s_mul_int_int(a, b): return vm.ValueInt(a.val * b.val)
def s_sub_int_int(a, b): return vm.ValueInt(a.val - b.val)