Macro choose_offer 

macro_rules! choose_offer {
    ( $choose:ident $offer:ident {
        $($p:ident ( $t:ty ) $o:ident),+
    } with $offerExt:ident) => { ... };
    ($choose:ident; $e:expr ; ) => { ... };
    ($choose:ident; $e:expr ; $p:ident ($t:ty) $(, $ps:ident ($ts:ty) )* ) => { ... };
    (offer_body $ext:ident $t:ident $c:ident ; $e:expr ; ) => { ... };
    (offer_body $ext:ident $t:ident $c:ident ; $e:expr ; $p:ident $(, $ps:ident)* ) => { ... };
    ($offer:ident $ext:ident; $($p:ident $t:ty),+) => { ... };
}