# astype proc

Source: https://ref.dm-lang.org/proc/astype
Added in BYOND 516.

### Format
- `astype(Val,Type)`
- `astype(Val)`


### Returns
> Val if Val is derived from Type; null otherwise.

### Args
- `Val`: An object instance.
- `Type`: An object prototype or instance. If no type is specified, it will be implied (see below).


Forcibly casts an object to a type, returning null if it isn't valid.

```dm /astype/
astype(gift, /obj/potion)?.Drink()
```

Similarly to `istype()`, the type can be implied. The implied type is determined as follows:

If `astype()` is on the right-hand side of an assignment operation, the left-hand side's var type is the implied type, just like with the `new()` operator. Otherwise, the var type of the first argument is the implied type, just as it is in `istype()`.

```dm /astype/
// if obstacle is of type /obj/box, it will be assigned to B; otherwise B is null
var/obj/box/B = astype(obstacle)
if(B?.closed) B.Open()

// B is assigned no matter what, but astype() will return null if it isn't an /obj/box
B = obstacle
if(astype(B)?.closed) B.Open()
```

### See also
- [istype proc](https://ref.dm-lang.org/proc/istype.md)
- [__IMPLIED_TYPE__ macro](https://ref.dm-lang.org/DM/preprocessor/__IMPLIED_TYPE__.md)