anchor.diff:  %% @see c_primop/2
   %% @see primop_args/1
   
  --spec primop_arity(c_primop()) -> non_neg_integer().
  +-spec primop_arity(c_primop()) -> arity().
   
   primop_arity(Node) ->
       length(primop_args(Node)).
  
positive.code:     Node#c_primop.args.
  
  
  %% @spec primop_arity(Node::cerl()) -> integer()
  %%
  %% @doc Returns the number of argument subtrees of an abstract
  %% primitive operation call.
  
negative.code:     false.
  
  
  %% @spec c_fname(Name::atom(), Arity::arity()) -> cerl()
  %% @equiv c_var({Name, Arity})
  %% @see fname_id/1
  %% @see fname_arity/1
  