Macro TryFrom

macro_rules! TryFrom {
    (($prim:ty) $(pub)* enum $name:ident { $($body:tt)* }) => { ... };
    (
        @collect_variants ($name:ident, $prim:ty),
        ($(,)*) -> ($($var_names:ident,)*)
    ) => { ... };
    (
        @collect_variants $fixed:tt,
        (#[$_attr:meta] $($tail:tt)*) -> $var_names:tt
    ) => { ... };
    (
        @collect_variants $fixed:tt,
        ($var:ident $(= $_val:expr)*, $($tail:tt)*) -> ($($var_names:tt)*)
    ) => { ... };
    (
        @collect_variants ($name:ident),
        ($var:ident $_struct:tt, $($tail:tt)*) -> ($($var_names:tt)*)
    ) => { ... };
    (
        @skip_meta $fixed:tt,
        (#[$_attr:meta] $($tail:tt)*) -> $var_names:tt
    ) => { ... };
    (
        @skip_meta $fixed:tt,
        ($var:ident $($tail:tt)*) -> $var_names:tt
    ) => { ... };
}

See the documentation for the macros module for details.