% primitive recursion
/pfact {
  {1} {*} primrec}.

%linear recursion
/lfact {
   {dup 0 eq}
   {pop 1}
   {dup pred}
   {*}
   linrec}.

% general recursion
/gfact {
    {0 eq}
    {succ}
    {dup pred}
    {i *}
    genrec}.

% binary recursion
/fib {
    {2 lt} {} {pred dup pred} {+} binrec}.