• Keep all your translated strings in one XML file;
• Generate Localizable.strings for each language;
• Generate Swift's enum with strings identifiers.

Sample input strings XML file:

<?xml version="1.0" encoding="UTF-8"?>
<strings>
    <string id="login">
        <en>Log in</en>
        <nl>Inloggen</nl>
        <ru>Вход</ru>
    </string>
    <string id="sign_in">
        <en>Sign in</en>
        <de>Anmelden</de>
    </string>
</strings>

Generating Localizable.strings:

$ ./make.sh strings.xml output output/Strings.swift

This will generate given enum to have auto-completion in code and avoid any typo errors:

/// Auto-generated

import Localizable

enum Strings {
    @Localizable static var login = "login"
    @Localizable static var sign_in = "sign_in"
}

1. Copy Resources/Localizable folder into project's Resources
2. Place your translations Strings.xml file into Resources
3. Add new Build Phase to generate strings

cd $SRCROOT/$TARGETNAME/Resources/Localizable
./make.sh $SCRIPT_INPUT_FILE_0 .. $SCRIPT_OUTPUT_FILE_0

• Input Files: $(SRCROOT)/$(TARGETNAME)/Resources/Strings.xml
• Output Files: $(SRCROOT)/$(TARGETNAME)/Strings.swift

As an option here is possible to reformat input source XML to keep languages in sorted order:

$ format.sh Strings.xml

This will overwrite existing file.

1. In Xcode select File ⭢ Swift Packages ⭢ Add Package Dependency...
2. Copy-paste repository URL: https://github.com/avdyushin/Localizable
3. Hit Next two times, under Add to Target select your build target.
4. Hit Finish

Using XML and XSLT for code generation