More Closure Fun

Here are some more closure test cases that work:

// Test the closures can be passed as parameters

def testClosureAsParam {

  var i = 0;

  callTenTimes(fn { i += 2; });

  Debug.assertEq(20, i);

  var s = StringBuilder();

  callTenTimes(fn { s.append("A"); });

  Debug.assertEq("AAAAAAAAAA", s.toString());

}

def callTenTimes(f:fn) {

  for i = 0; i < 10; ++i {

    f();

  }

}

// Test that nested closures work.

def testNestedClosures {

  let makeCounter = fn n:int -> fn -> int {

    return fn -> int {

      return n++;

    };

  };

  

  let c = makeCounter(2);

  Debug.assertEq(2, c());

  Debug.assertEq(3, c());

}

// Test that an inner closure can access a variable two levels out.

def testNestedClosures2 {

  var i = 0;

  let makeCounter = fn -> fn -> int {

    return fn -> int {

      return i++;

    };

  };

  let c = makeCounter();

  let d = makeCounter();

  Debug.assertEq(0, c());

  Debug.assertEq(1, c());

  Debug.assertEq(2, d());

  Debug.assertEq(3, d());

}

One thing that does not work yet is closure variables that are large structs or tuples - basically any local variable that is not an object reference or a primitive type. It shouldn't be hard to fix, however.