closures

I would like to do the following in swift code: I have to call my api in order to update several items. So I call the api for each item asynchronously. Each api call executes a callback function when it's done. These callbacks decrease a counter, so that when the counter reaches 0 I know that all my api calls are completed. When the counter reaches 0 I would like to call a final callback function (once, when all calls are complete), in order to update my UI and so forth. This final callback is passes to my service in the beginning and stored in a class property for later execution. Executable

I recently got into closures and anonymous functions, and I'm wondering if my code is the right way to do it (it works!): newInput.onchange = function(x){ return function(){ PassFileName(x); } }(counter); so this is in a loop that "saves" the current 'counter' value (1,2,3...). If I didn't have the return function, then 'counter' will always be the last value of 'counter'. Am I approaching this correctly with that code? or is there a better way to "capture" the current counter and attach it to an onchange event? thank you! Yes, you're approaching it correctly, but for maximum compatibility

I'm trying to implement the State monad in Rust ( State is effectively a wrapper over a function which takes original state and returns modified state and some result). This is how one can implement State in Haskell (monad operations where renamed to unit and bind for sake of simplicity): data State s u = State { run :: s -> (u, s) } -- return unit :: u -> State s u unit u = State $ \s -> (u, s) -- (>>=) bind :: State s u -> (u -> State s a) -> State s a bind m f = State $ \s -> let (u, s') = run m s in run (f u) s' So I try to rewrite it in Rust: pub struct State<'r, S, U> { priv run: 'r |S|

Consider this code: PS> $timer = New-Object Timers.Timer PS> $timer.Interval = 1000 PS> $i = 1; PS> Register-ObjectEvent $timer Elapsed -Action { write-host 'i: ' $i }.GetNewClosure() PS> $timer.Enabled = 1 i: 1 i: 1 i: 1 ... # wait a couple of seconds and change $i PS> $i = 2 i: 2 i: 2 i: 2 I assumed that when I create new closure ( { write-host 'i: ' $i }.GetNewClosure() ) value of $i will be tied to this closure. But not in this case. Afer I change the value, write-host takes the new value. On the other side, this works: PS> $i = 1; PS> $action = { write-host 'i: ' $i }.GetNewClosure() PS>