Instead of adding functionality to a desktop publishing system, a different approach is to export the document and process it outside that system. Any kerning features can then be applied to the document using tools ranging from ordinary text editors to programs specially developed for this task. The modified document is then imported back into the desktop publishing system. Many systems permit this operation, either by converting the document with import and export functions, or by making their internal document format an open standard. The benefit of this approach is that some complex typesetting functions that may be hard to implement through plug-ins (kerning in particular) may be relatively easy to implement through separate tools.