quick_error::quick_error!

macro_rules! quick_error {
    (// public with docstring
        $(#[$meta:meta])*
        pub enum $name:ident {
           $(
               #[doc=$doc:expr]
               $item:ident $( ( $($var:ident : $typ:ty),* ) )* { $($funcs:tt)* }
           )*
        }
    ) => { ... };
    (// private with docstring
        $(#[$meta:meta])*
        enum $name:ident {
           $(
               #[doc=$doc:expr]
               $item:ident $( ( $($var:ident : $typ:ty),* ) )* { $($funcs:tt)* }
           )*
        }
    ) => { ... };
    (// public no meta
        $(#[$meta:meta])*
        pub enum $name:ident {
           $(
               $item:ident $( ( $($var:ident : $typ:ty),* ) )* { $($funcs:tt)* }
           )*
        }
    ) => { ... };
    (// private no meta
        $(#[$meta:meta])*
        enum $name:ident {
           $(
               $item:ident $( ( $($var:ident : $typ:ty),* ) )* { $($funcs:tt)* }
           )*
        }
    ) => { ... };
    (IMPLEMENTATIONS
        $name:ident {
            $(
                $item:ident $( ( $($var:ident : $typ:ty),* ) )* { $($funcs:tt)* }
            )*
        }
    ) => { ... };
    (FIND_DISPLAY_IMPL $item:ident $me:ident $fmt:ident
        [ $( ( $($var:ident)* ) )* ]
        { display($($exprs:expr),*) $($tail:tt)* }
    ) => { ... };
    (FIND_DISPLAY_IMPL $item:ident $me:ident $fmt:ident
        [ $( ( $($var:ident)* ) )* ]
        { $t:tt $($tail:tt)* }
    ) => { ... };
    (FIND_DISPLAY_IMPL $item:ident $me:ident $fmt:ident
        [ $( ( $($var:ident)* ) )* ]
        { }
    ) => { ... };
    (FIND_DESCRIPTION_IMPL $item:ident $me:ident $fmt:ident
        [ $( ( $($var:ident)* ) )* ]
        { description($expr:expr) $($tail:tt)* }
    ) => { ... };
    (FIND_DESCRIPTION_IMPL $item:ident $me:ident $fmt:ident
        [ $( ( $($var:ident)* ) )* ]
        { $t:tt $($tail:tt)* }
    ) => { ... };
    (FIND_DESCRIPTION_IMPL $item:ident $me:ident $fmt:ident
        [ $( ( $($var:ident)* ) )* ]
        { }
    ) => { ... };
    (FIND_CAUSE_IMPL $item:ident
        [ $( ( $($var:ident)* ) )* ]
        { cause($expr:expr) $($tail:tt)* }
    ) => { ... };
    (FIND_CAUSE_IMPL $item:ident
        [ $( ( $($var:ident)* ) )* ]
        { $t:tt $($tail:tt)* }
    ) => { ... };
    (FIND_CAUSE_IMPL $item:ident
        [ $( ( $($var:ident)* ) )* ]
        { }
    ) => { ... };
    (FIND_FROM_IMPL $name:ident $item:ident
        [ $( ( $($var:ident : $typ:ty)* ) )* ]
        { from() $($tail:tt)* }
    ) => { ... };
    (FIND_FROM_IMPL $name:ident $item:ident
        [ ]
        { from($ftyp:ty) $($tail:tt)* }
    ) => { ... };
    (FIND_FROM_IMPL $name:ident $item:ident
        [ $( ( $($var:ident : $typ:ty)* ) )* ]
        { from($fvar:ident : $ftyp:ty) -> ($($expr:expr),*) $($tail:tt)* }
    ) => { ... };
    (FIND_FROM_IMPL $name:ident $item:ident
        [ $( ( $($var:ident : $typ:ty)* ) )* ]
        { $t:tt $($tail:tt)* }
    ) => { ... };
    (FIND_FROM_IMPL $name:ident $item:ident
        [ $( ( $($var:ident : $typ:ty)* ) )* ]
        { }
    ) => { ... };
    (ERROR_CHECK display($($exprs:expr),*) $($tail:tt)*) => { ... };
    (ERROR_CHECK description($expr:expr) $($tail:tt)*) => { ... };
    (ERROR_CHECK cause($expr:expr) $($tail:tt)*) => { ... };
    (ERROR_CHECK from() $($tail:tt)*) => { ... };
    (ERROR_CHECK from($ftyp:ty) $($tail:tt)*) => { ... };
    (ERROR_CHECK from($fvar:ident : $ftyp:ty) -> ($($e:expr),*) $($tail:tt)*) => { ... };
    (ERROR_CHECK) => { ... };
}

Main macro that does all the work