anchor.diff:  %% expand body.
   exp_predef(['match-spec'|Body], Env, St0) ->
       %% Expand it like a match-lambda.
  -    {Exp,St1} = expand_ml_clauses(Body, Env, St0),
  +    {Exp,St1} = exp_ml_clauses(Body, Env, St0),
       MS = lfe_ms:expand(Exp),
       {yes,MS,St1};
   %% (qlc (lc (qual ...) e ...) opts)
  
positive.code:     mapfoldl(fun (Q, S) -> exp_qlc_qual(Q, Env, S) end, St, Qs).
  
  exp_qlc_qual(['<-',P0,['when'|G0],E0], Env, St0) ->
      {P1,St1} = expand(P0, Env, St0),
      {G1,St2} = expand_tail(G0, Env, St1),
      {E1,St3} = expand(E0, Env, St2),
      {['<-',P1,['when'|G1],E1],St3};
  exp_qlc_qual(['<-',P0,E0], Env, St0) ->
      {P1,St1} = expand(P0, Env, St0),
      {E1,St2} = expand(E0, Env, St1),
      {['<-',P1,E1],St2};
  exp_qlc_qual(T, Env, St) -> expand(T, Env, St).
  
  %% exp_bif(Bif, Args) -> Expansion.
  
  
negative.code: %%  Expand all the macros in an expression.
  
  expand_expr_all(F, Env) ->
      {Ef,_} = exp_form(F, Env, #mac{expand=true}),
      Ef.
  
  %% expand_forms(FileForms, Env) ->
  