# Spread assignment

In a spread assignment, a variable can be prefixed with `...` in front of the variable, all the remaining elements can be expanded into the variable. This is called a spread assignment.

```erg
[x, ... .y] = [1, 2, 3]
assert x == 1
assert y == [2, 3].
x, ... .y = (1, 2, 3)
assert x == 1
assert y == (2, 3)
```

## Extract assignment

If nothing is written after `...`, the remaining elements are ignored and an assignment is made. This type of expansion assignment is specifically called an extract assignment.
Extract assignment is a useful syntax for bringing certain attributes local to a module or record.

```erg
{sin; cos; tan; ...} = import "math"
```

This way, `sin`, `cos`, `tan` can be used locally from then on.

You can do the same with records.

```erg
record = {x = 1; y = 2}
{x; y; ...} = record
```

If you want to expand all of them, use `{*} = record`, this is equivalent to `open` in OCaml and so on.

```erg
record = {x = 1; y = 2}
{*} = record
assert x == 1 and y == 2
```

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