Localizing Code Comments and String Literals

Mark up code zones to replace them with code that’s localized for the current user.


If you’re writing a playground book for distribution in multiple locales, you can localize the comments and string literals on each page using a comment syntax that delimits a zone for localization.

Add Localization Delimiters

Specify the code you want to make localizable by wrapping it within a delimiter; for example:


Each delimiter carries a unique zone identifier (for example, welcome1, welcome2, and so forth) that matches an entry in the LocalizableCode.strings file you define for each page.

You can also use inline comment delimiters to make string literals localizable; for example:

let message = "/*#-localizable-zone(welcome2)*/Hello!/*#-end-localizable-zone*/"

Create a Localization Strings File

When a user opens a page in your book, the system looks in the appropriate language directory (for example, the page’s PrivateResources/de.lproj directory for strings localized in German) for the LocalizableCode.strings file. It then matches the delimeters with their corresponding zone ID, and substitutes the text string in the page with the localized text.

Format localization strings files as a list of localization identifiers followed by the localized string. The following example defines localized forms of the content identified by welcome1 and welcome2:

/* Initial greeting. */
"welcome1" = "Willkommen!";

/* Second greeting. */
"welcome2" = "Guten Tag!";

Localized versions of comments and strings appear on devices set to the appropriate locale:


let message = "Guten Tag!"

See Also


Writing Prose for a Playground Page

Add comment markers in your Swift code to mark text as prose.

Specifying Editable Regions in a Playground Page

Guide learning by marking code that learners can change or copy forward.

Hiding Code from a Playground Page

Use special Swift comments to hide code from display but continue to run it.

Customizing the Completions in the Shortcut Bar

Guide learners toward a solution by hiding some symbols and showing others.