## Builtin: Array Arithmetic Expressions

Now that we have support for string-based arithmetic, perhaps we might want to also implement array-based arithmetic? This issue will discuss possible syntax ideas that we could pursue.

# Proposal # 1

This approach is commonly used in functional languages, so it might also be a natural fit here. Define a variable name to describe each element in the array, and then follow it with a mathematical expression to apply with each element in the array.

`@[ELEMENT -> EXPR, ARRAY EXPR]`

## Examples

### Example # 1

```
let array = [1 2 3]
for result in @[x -> x * x, array]
echo $result
end
```

### Output # 1

```
1
4
9
```

### Example # 2

```
let array = [1 2 3]
let value = 3
for result in @[x -> x * value, array]
echo $result
end
```

### Output # 2

```
3
6
9
```