# appendInterpolation(_:) Appends a type, convertible to a string by using a default format specifier, to a string interpolation. ``` mutating func appendInterpolation(_ value: T) where T : _FormatSpecifiable ``` ## Parameters `value` A primitive type to append, such as , , or . ## Discussion Don’t call this method directly; it’s used by the compiler when interpreting string interpolations. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)