anchor.diff:    case AST of
       {'ES:BEGIN', First, Next} ->
         interpret_begin(First, Next, Env);
  +    {'ES:CONS', Hd, Tl} ->
  +      interpret_cons(Hd, Tl, Env);
       {'ES:DEFINE', Var, Expr} ->
         interpret_define(Var, Expr, Env);
       {'ES:GLOVAR', Var} ->
  
positive.code:     interpret(Handler, bind_formals([EVar], [{Class, Reason, Stack}], Env))
    end.
  
  %% Auxiliary helpers -----------------------------------------------------------
  
  bind_formals([], [], Env) ->
  
negative.code:     {'ES:QUOTE', Value} ->
        interpret_quote(Value);
      {'ES:TRY', Expr, Var, Body, EVar, Handler, After} ->
        interpret_try(Expr, Var, Body, EVar, Handler, After, Env);
      {'ES:TUPLE', Exprs} ->
        interpret_tuple(Exprs, Env)
    end.
  
  interpret_begin(First, Next, Env) ->
    interpret(First, Env),
    interpret(Next, Env).
  
  interpret_cons(Hd, Tl, Env) ->
    [interpret(Hd, Env) | interpret(Tl, Env)].
  
  interpret_define(Var, Expr, Env) ->
    %% This is restricted, by macro-expansion and parsing, to the top-level.
  