Deafult::default() 宏实现不同数据类型默认值
温馨提示：觉得有帮助的话, 给我点赞哦～
macro_rules! default_impl {
($t:ty, $v:expr, $doc:tt) => {
#[stable(feature = "rust1", since = "1.0.0")]
impl Default for $t {
#[inline]
#[doc = $doc]
fn default() -> $t {
$v
}
}
};
}
default_impl! { (), (), "Returns the default value of `()`" }
default_impl! { bool, false, "Returns the default value of `false`" }
default_impl! { char, '\x00', "Returns the default value of `\\x00`" }
default_impl! { usize, 0, "Returns the default value of `0`" }
default_impl! { u8, 0, "Returns the default value of `0`" }
default_impl! { u16, 0, "Returns the default value of `0`" }
default_impl! { u32, 0, "Returns the default value of `0`" }
default_impl! { u64, 0, "Returns the default value of `0`" }
default_impl! { u128, 0, "Returns the default value of `0`" }
default_impl! { isize, 0, "Returns the default value of `0`" }
default_impl! { i8, 0, "Returns the default value of `0`" }
default_impl! { i16, 0, "Returns the default value of `0`" }
default_impl! { i32, 0, "Returns the default value of `0`" }
default_impl! { i64, 0, "Returns the default value of `0`" }
default_impl! { i128, 0, "Returns the default value of `0`" }
default_impl! { f32, 0.0f32, "Returns the default value of `0.0`" }
default_impl! { f64, 0.0f64, "Returns the default value of `0.0`" }
温馨提示：觉得有帮助的话, 给我点赞哦～
