{-# LANGUAGE ScopedTypeVariables #-}
{-
Copyright 2011 Ken Takusagawa
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
-}

module Factor_cmd  where{
import System.Process;

factor :: Integer -> IO([](Integer));
factor x = ((readProcess "factor" [(show x)] "") >>= (return . tail . (map read) . words));
is_prime :: Integer -> IO(Bool);
is_prime x = (case (compare x 1) of {
  GT-> ((factor x) >>= (return . length) >>= (return . (\lambda_case_var ->case lambda_case_var of {
  1-> True;
  _ -> False
})));
  _ -> (return False)
});
next_prime :: Integer -> IO(Integer);
next_prime try = ((is_prime try) >>= (\lambda_case_var ->case lambda_case_var of {
  True-> (return try);
  _ -> (next_prime ((+) 1 try))
}))
}