% tail_return - Package return values for tail_feval
%
% tail_return :: A{1:N} -> thunk(A{1:N}).
%
% thunk(B{1:M}) ::= 
%    exists C{1:L} . cell { C{1:L}->B{1:M}, cell { C{1:L} } }
%  | cell { {0}, cell { B{1:L} } }
%  | void -> B{1:M}.
function ret=tail_return(varargin), ret={0,varargin}; end
