Macro conda 

macro_rules! conda {
    ($($g:expr),*) => { ... };
    ($g0:expr, $($g:expr),+; $($rest:tt)*) => { ... };
    ($g0:expr; $($rest:tt)*) => { ... };
}

Creates a goal that succeeds if any of its lines succeeds. Only the first line that succeeds can contribute values.

A line (separated by ;) succeeds if all of its goals (separated by ,) succeed.