// Example code.
//  - NOTE: The syntax is very likely to change, and this may be not
//    up-to-date.


function square(int n) = ($n * $n)


function f(int x, int y, str s, bool b) =
	(  $x + 4 * ($y + 5) == $y - $x + 4
	|| $b
	&& (int $s == $x || $s == str $x)
	)


// Recursion.
function f(int n) = (n + f n);


procedure int p(str x, int n, bool b)
{
	int ret;

	// Pass $x into `sed`, store result in $s.
	s <= @sed "-E" "s/x/y/g" <= $x;

	// Pass $x into grep, get return code.
	ret <- @grep "-qE" "x" <= $s;

	if ($ret == 0 && b)
	{
		return 0 /* return/exit code */, int $x /* return value */;
	}
	else
	{
		return 1, 0;
	}
}


procedure int q()
{
	str s;
	read_line $s;
	print $s;
	print_err $s;
	return 0, 42;
}


procedure int r()
{
	int ret;
	str stdout, stderr;
	int value;

	// Evaluate an expression.
	value = square 7 - 5;

	// Get all data from a procedure call.
	(ret, value, stdout, stderr) <- p "x" 42 (3 == 4) <= "stdin";

	// Minimal procedure call.
  //  - stdout, stderr, stdin are passed through.
	//  - Non-zero return code causes this procedure to return with that return
	//    code.
	q;

	// Get some data from a procedure call.
  //  - `:` means pass through, `_` means ignore.
	(ret, value) <- q;
	(ret, _, :, stderr) <- q;
	(value, stdout, stderr) <= q;
	value <= q;
	(value, stdout) <= q;
	(_, stdout) <= q;

	return 0, $value;
}


procedure main()
{
	while true
	{
		@date "-u";
		r;
	}

	return 127;	// no return value, only return code
}


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