== case x1 of
== Rnone =>
== Rplus(left,right)=>rec1,rec2.
== Rinit(loc,T,x,v)=>
== Rframe(loc,T,x,L)=>
== Rsframe(lnk,tag,L)=>
== Reffect(loc,ds,knd,T,x,f)=> knd
== Rsends(ds,knd,T,l,dt,g)=>
== Rpre(loc,ds,a,T,P)=>
== Raframe(loc,k,L)=>
== Rbframe(loc,k,L)=>
== Rrframe(loc,x,L)=>