/**
* ioState :: IO a -> State IO a
*
* @param M\IO $io
*
* @return M\State
*/
function ioState(M\IO $io)
{
return M\State::of(function ($state) use($io) {
list($key, $data) = $state;
$value = $io->run();
$data[$key] = $value;
$newState = [$key, $data];
return [$value, $newState];
});
}
/**
* until :: (a -> Bool) -> (a -> b -> b) -> b -> IO a -> IO b
*
* @param callable $predicate (a -> Bool)
* @param callable $do (a -> b -> a)
* @param mixed $base b
* @param M\IO $ioValue IO a
*
* @return M\IO
*/
function until(callable $predicate, callable $do, $base, M\IO $ioValue)
{
return M\IO::of(function () use($predicate, $do, $base, $ioValue) {
do {
$value = $ioValue->run();
$isFulfilled = $predicate($value);
$base = $isFulfilled ? $base : call_user_func($do, $value, $base);
} while (!$isFulfilled);
return $base;
});
}
/**
* tryCatch :: Exception e => IO a -> (e -> IO a) -> IO a
*
* @param M\IO $io
* @param callable $catchFunction
*
* @return M\IO
*/
function tryCatch(M\IO $io = null, callable $catchFunction = null)
{
return call_user_func_array(f\curryN(2, function (M\IO $io, callable $catchFunction) {
return M\IO::of(function () use($io, $catchFunction) {
try {
return $io->run();
} catch (\Exception $e) {
return call_user_func($catchFunction, $e);
}
});
}), func_get_args());
}
