anchor.diff:      Else = enc_pre_cg_1(Else0, StL, outside_seq),
       {'try',Try,{P,Succ},Else,Dst};
   enc_pre_cg_nonbuilding(Imm, _) -> Imm.
  -
   
   %%%
   %%% Code generation for encoding.
  
positive.code:     Src = mk_val(Src0),
      Dst = mk_val(Dst0),
      emit([Dst," = ",Src," - ",Int]);
  enc_cg({'try',Try,{P,Succ},Else,Dst}) ->
      emit([mk_val(Dst)," = try "]),
      enc_cg(Try),
  
negative.code:     [{lc,per_fixup(B),V,L}|per_fixup(T)];
  per_fixup([{lc,B,V,L,Dst}|T]) ->
      [{lc,per_fixup(B),V,L,Dst}|per_fixup(T)];
  per_fixup([{set,_,_}=H|T]) ->
      [H|per_fixup(T)];
  per_fixup([{sub,_,_,_}=H|T]) ->
      [H|per_fixup(T)];
  per_fixup([{'try',Try0,{P,Succ0},Else0,Dst}|T]) ->
  