Macro match_each_native_ptype 

macro_rules! match_each_native_ptype {
    (
        $self:expr,integral: |
        $integral_enc:ident |
        $intbody:block,floating: |
        $floating_point_enc:ident |
        $floatbody:block
    ) => { ... };
    (
        $self:expr,unsigned: |
        $unsigned_enc:ident |
        $unsigned_body:block,signed: |
        $signed_enc:ident |
        $signed_body:block,floating: |
        $floating_point_enc:ident |
        $floating_point_body:block
    ) => { ... };
    ($self:expr, | $tname:ident | $body:block) => { ... };
}

Macro to match over each PType, binding the corresponding native type (from NativePType)