格式

一个实用软件包，可以更容易地使用格式化工具

用法

将依赖项添加到您的 Cargo.toml

[dependencies]
format = "0.2"

并使用 lazy_format 宏

struct Foo(usize);

impl Debug for Foo {
    fn fmt(&self, f: &mut Formatter) -> Result {
        let alternate = f.alternate();
        let bar = lazy_format!(|f| if alternate {
            write!(f, "{:#x}", self.0)
        } else {
            write!(f, "{:x}", self.0)
        });
        f.debug_tuple("Foo")
            .field(&format_args!("{}", bar))
            .finish()
    }
}

或格式类型之一

struct Foo(usize);

impl Debug for Foo {
    fn fmt(&self, f: &mut Formatter) -> Result {
        let alternate = f.alternate();
        let bar = LowerHex(|f| {
            if alternate {
                write!(f, "{:#x}", self.0)
            } else {
                write!(f, "{:x}", self.0)
            }
        });
        f.debug_tuple("Foo")
            .field(&format_args!("{:x}", bar))
            .finish()
    }
}