# Sets

Sets represent an unordered collection of unique elements. These are
implemented using hash tables.

```tomo
a := {10, 20, 30}
b := {20, 30}
>> a:overlap(b)
= {20}
```

Here’s the Markdown documentation for set functions:

---

## Set Functions

### `has`

**Description:**  
Checks if the set contains a specified item.

**Usage:**  
```tomo
has(set:{T}, item:T) -> Bool
```

**Parameters:**

- `set`: The set to check.
- `item`: The item to check for presence.

**Returns:**  
`yes` if the item is present, `no` otherwise.

**Example:**  
```tomo
>> {10, 20}:has(20)
= yes
```

---

### `add`

**Description:**  
Adds an item to the set.

**Usage:**  
```tomo
add(set:{T}, item: T) -> Void
```

**Parameters:**

- `set`: The mutable reference to the set.
- `item`: The item to add to the set.

**Returns:**  
Nothing.

**Example:**  
```tomo
>> nums:add(42)
```

---

### `add_all`

**Description:**  
Adds multiple items to the set.

**Usage:**  
```tomo
add_all(set:&{T}, items: [T]) -> Void
```

**Parameters:**

- `set`: The mutable reference to the set.
- `items`: The array of items to add to the set.

**Returns:**  
Nothing.

**Example:**  
```tomo
>> nums:add_all([1, 2, 3])
```

---

### `remove`

**Description:**  
Removes an item from the set.

**Usage:**  
```tomo
remove(set:&{T}, item: T) -> Void
```

**Parameters:**

- `set`: The mutable reference to the set.
- `item`: The item to remove from the set.

**Returns:**  
Nothing.

**Example:**  
```tomo
>> nums:remove(42)
```

---

### `remove_all`

**Description:**  
Removes multiple items from the set.

**Usage:**  
```tomo
remove_all(set:&{T}, items: [T]) -> Void
```

**Parameters:**

- `set`: The mutable reference to the set.
- `items`: The array of items to remove from the set.

**Returns:**  
Nothing.

**Example:**  
```tomo
>> nums:remove_all([1, 2, 3])
```

---

### `clear`

**Description:**  
Removes all items from the set.

**Usage:**  
```tomo
clear(set:&{T}) -> Void
```

**Parameters:**

- `set`: The mutable reference to the set.

**Returns:**  
Nothing.

**Example:**  
```tomo
>> nums:clear()
```

---

### `with`

**Description:**  
Creates a new set that is the union of the original set and another set.

**Usage:**  
```tomo
with(set:{T}, other: {T}) -> {T}
```

**Parameters:**

- `set`: The original set.
- `other`: The set to union with.

**Returns:**  
A new set containing all items from both sets.

**Example:**  
```tomo
>> {1, 2}:with({2, 3})
= {1, 2, 3}
```

---

### `overlap`

**Description:**  
Creates a new set with items that are in both the original set and another set.

**Usage:**  
```tomo
overlap(set:{T}, other: {T}) -> {T}
```

**Parameters:**

- `set`: The original set.
- `other`: The set to intersect with.

**Returns:**  
A new set containing only items present in both sets.

**Example:**  
```tomo
>> {1, 2}:overlap({2, 3})
= {2}
```

---

### `without`

**Description:**  
Creates a new set with items from the original set but without items from another set.

**Usage:**  
```tomo
without(set:{T}, other: {T}) -> {T}
```

**Parameters:**

- `set`: The original set.
- `other`: The set of items to remove from the original set.

**Returns:**  
A new set containing items from the original set excluding those in the other set.

**Example:**  
```tomo
>> {1, 2}:without({2, 3})
= {1}
```

---

### `is_subset_of`

**Description:**  
Checks if the set is a subset of another set.

**Usage:**  
```tomo
set:is_subset_of(other: {T}, strict: Bool = no) -> Bool
```

**Parameters:**

- `set`: The set to check.
- `other`: The set to compare against.
- `strict`: If `yes`, checks if the set is a strict subset (does not equal the other set).

**Returns:**  
`yes` if the set is a subset of the other set (strictly or not), `no` otherwise.

**Example:**  
```tomo
>> {1, 2}:is_subset_of({1, 2, 3})
= yes
```

---

### `is_superset_of`

**Description:**  
Checks if the set is a superset of another set.

**Usage:**  
```tomo
is_superset_of(set:{T}, other: {T}, strict: Bool = no) -> Bool
```

**Parameters:**

- `set`: The set to check.
- `other`: The set to compare against.
- `strict`: If `yes`, checks if the set is a strict superset (does not equal the other set).

**Returns:**  
`yes` if the set is a superset of the other set (strictly or not), `no` otherwise.

**Example:**  
```tomo
>> {1, 2, 3}:is_superset_of({1, 2})
= yes
```