# Fn

---

```text
Fn_class `alias Enum[.partial; .complete; .iterator; .closure; .bound; .regex; .native]

Fn[Fn_class; RETURN_TYPE; ARGS; STATE; List]
```

## Transient Union Return

### \`return_value

### \`return_error

### \`return_some

### \`return_none

## Transient Union Return Chaining

# Iterating

## \`has_next

## Transient Union Yield

### \`yield_value

### \`yield_error

### \`yield_some

### \`yield_none

```text
fn : Fn[x] $ ( @ 1 .. x { `yield_some 2 * x } )
it : fn `sync 10
// invoking
@ it { `log v }[v] // Opton[Int[...]].v $ (.some : 2); Opton[Int[...]].v $ (.some : 4)
// same as above
@ `has_next it { `log it() }
```

# Calling

## \`call_async

```text
task : `call_async fn
value : `task_wait task
```

## \`call_sync

```text
fn `call_sync args // `task_wait fn `call_async args
```

## \`call_native

For calling native code