{-# LANGUAGE
GADTs,
TemplateHaskell,
ScopedTypeVariables
#-}
-----------------------------------------------------------------------------
-- |
-- Module : Main
-- Author : Matthew Mirman ( mmirman@andrew.cmu.edu )
-- Stability : experimental
-- Portability : portable
-- Description : An example module for Control.Monad.Imperative
--
-- Copyright (C) 2012 Matthew Mirman
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU 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 General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>
module Main where
import Control.Monad.Imperative
swap(r1, r2) = function $ do
{
z <- new auto;
z =: r1;
r1 =: r2;
r2 =: z;
};
imperativeId(r1) = function $ do
{
return' r1;
};
factorial = function $ do
{
a <- new 0;
n <- new 1;
for' ( a =: Lit 1 , a <. Lit 11 , a +=: Lit 1 ) $ do
{
n *=: a;
if' ( a <. Lit 7)
continue';
if' ( a >. Lit 5)
break';
return' a;
};
a =: imperativeId(a);
swap( (&)n , (&)a);
return' n;
};
main = do
t <- runImperative factorial
putStrLn $ "Some Factorial: "++show (t :: Int)