Macro match_each_pvalue 

macro_rules! match_each_pvalue {
    (
        $this:expr,uint: |
        $vuint:ident |
        $buint:block,int: |
        $vint:ident |
        $bint:block,float: |
        $vfloat:ident |
        $bfloat:block
    ) => { ... };
}

Utility macro that makes it easy to write expressions generic over the different PValue variants.