One tip for preparing for non-interactive use is to thoroughly factor your in-
terface from the functionality. There is more on this in Part III of this book.
Building on the Past
Look at what you have. Most organizations (and individuals)
have a vast amount of preexisting code. Some of it is reusable;
other parts of this code store should be rewritten...someday.
Learn from Apple's example: The Finder in Mac OS X was not
written from scratch. One of the reasons that it is written in
Carbon rather than Cocoa is so that some parts of the Mac OS
9 Finder code could be included in the first releases of Mac OS
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