let rec get_vars (atms : int list) (vars : int list)
: term list list -> int list =
let rec help vars = function
| Var(n)::tail -> if List.mem n atms then
help vars tail
else
help (insert n vars) tail
| [] -> vars
| _ -> failwith "Unifyxor.get_vars: only Var(_) allowed here"
in
function
| eqn::eqns -> get_vars atms (help vars eqn) eqns
| [] -> vars