# Union

---

```text
Union[TAG | TRANSIENT] Collection[VAR_TREE_LIST; TYPE.SYMBOL]]
```

## Type Body Object Definitions

```c
typedef struct {
    kpl_ptr var_tree, var_list;
} kpl_type_body_union;
```

# Alias

```text
Tag[Collection[VAR_TREE_LIST; TYPE.SYMBOL]] `alias Union[[TAG] Collection[VAR_TREE_LIST; TYPE.SYMBOL]]

Transient[Collection[VAR_TREE_LIST; TYPE.SYMBOL]] `alias Union[[TRANSIENT] Collection[VAR_TREE_LIST; TYPE.SYMBOL]]
```

## Tag Example

```text
u : Tag[I64.a; I64.b; I64.c] $ (.c : 5)

# u {
    .c {[c] c ... }
    { ... } // default
}
```

# Operators

## ``take`

# Transient Unions

Return multiple types from a function

Can only be retuned from functions and operations. The inner value must be moved out

## Alias

```text
Result[Generic.T] `alias Transient[Generic.T.value; Void.null; Error.error]

Iteration[Generic.T] `alias Transient[Generic.T.value; Void.null; Void.done; Error.error]
```

## Default Operation

When a transient union is assigned the first type specified is moved out.

If no match is used and if the type is not the first specified a result with an error is returned

```text
z : x / y // Result[...]
z // is value if y is not zero
```
## Operators

### \`value

### \`error

### \`null