Macro tasks 

macro_rules! tasks {
    (
        $(
            $name:ident($($field:ident : $tp:ident),*) => $res:tt
        ),* $(,)?
    ) => { ... };
    (@DISPL $res:ident $disp:ident Term) => { ... };
    (@DISPL $res:ident $disp:ident bool) => { ... };
    (@TPBORROW Term) => { ... };
    (@TPOWN Term) => { ... };
    (@TPBORROW str) => { ... };
    (@TPOWN str) => { ... };
    (@FROMPRE Term $name:ident $f:ident) => { ... };
    (@FROMPRE str $name:ident $f:ident) => { ... };
    (@FROMPRE bool $name:ident $f:ident) => { ... };
    (@CONV Term $name:ident $f:ident) => { ... };
    (@CONV str $name:ident $f:ident) => { ... };
    (@CONV SolverRule $name:ident $f:ident) => { ... };
}