# Regex metacharacters

## Function

Explain the common usage of regular metacharacters such as ^, $, ., | and so on.

## Syntax

```bt
regex(pattern, flags)
```

## Parameters

| Parameters | Type | Required | Default value | Description |
| ------ | ------ | ------ | ------ | ------ |
| pattern | String | No | '' | Regular body containing metacharacters. |
| flags | String | No | '' | Regular flags. |

## Return value

| Type | Description |
| ------ | ------ |
| Regex | Returns a Regex object. |

## Example

```bt
rule = regex('^(BT|Rust)$', '')
result = rule.test('Rust')

// Output: true
print result
```

## Notes

- When it is necessary to match the metacharacter itself, escape characters should be written in pattern according to string rules.