envopt:通过定义结构来解析环境变量

包容 通过定义结构来解析环境变量。 例子 use envopt :: EnvOpt; #[derive(EnvOpt)] pub enum EnvOpts { #[envopt(name = "FOO" )] Foo, #[envopt(name = "BAR" , default = "default-bar" )] Bar, } pub fn main () { EnvOpts :: validate_or_exit (); println! ( "FOO: {}" , EnvOpts :: Foo. value_or_exit ()); println! ( "BAR: {}" , EnvOpts :: Bar. value_or_exit ()); }