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# CustomDebugStringConvertible

A type with a customized textual representation suitable for debugging
purposes.

```
protocol CustomDebugStringConvertible
```

## Overview

Swift provides a default debugging textual representation for any type.
That default representation is used by the `String(reflecting:)`
initializer and the `debugPrint(_:)` function for types that don’t provide
their own. To customize that representation, make your type conform to the
`CustomDebugStringConvertible` protocol.

Because the `String(reflecting:)` initializer works for instances of *any*
type, returning an instance’s `debugDescription` if the value passed
conforms to `CustomDebugStringConvertible`, accessing a type’s
`debugDescription` property directly or using
`CustomDebugStringConvertible` as a generic constraint is discouraged.

> Note: Calling the `dump(_:_:_:_:)` function and printing in the debugger
> uses both `String(reflecting:)` and `Mirror(reflecting:)` to collect
> information about an instance. If you implement
> `CustomDebugStringConvertible` conformance for your custom type, you may
> want to consider providing a custom mirror by implementing
> `CustomReflectable` conformance, as well.

# Conforming to the CustomDebugStringConvertible Protocol

Add `CustomDebugStringConvertible` conformance to your custom types by
defining a `debugDescription` property.

For example, this custom `Point` struct uses the default representation
supplied by the standard library:

```
struct Point {
    let x: Int, y: Int
}

let p = Point(x: 21, y: 30)
print(String(reflecting: p))
// Prints "Point(x: 21, y: 30)"
```

After adding `CustomDebugStringConvertible` conformance by implementing the
`debugDescription` property, `Point` provides its own custom debugging
representation.

```
extension Point: CustomDebugStringConvertible {
    var debugDescription: String {
        return "(\(x), \(y))"
    }
}

print(String(reflecting: p))
// Prints "(21, 30)"
```

---

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