== case R of
== Rnone => <0,
>
== Rplus(left,right)=>rec1,rec2.<0,
>
== Rinit(loc,T,x,v)=> <1,x>
== Rframe(loc,T,x,L)=> <2,x>
== Rsframe(lnk,tag,L)=> <3,lnk,tag>
== Reffect(loc,ds,knd,T,x,f)=> <4,knd,x>
== Rsends(ds,knd,T,l,dt,g)=> <5,knd,l>
== Rpre(loc,ds,a,T,P)=> <6,a>
== Raframe(loc,k,L)=> <7,k>
== Rbframe(loc,k,L)=> <8,k>
== Rrframe(loc,x,L)=> <9,x>