Brown Jenkin said:
But game mechanics can't be copyrighted, just the description of them. So a software program that uses those mechanics but doesn't reproduce the text of those mechanics should be safe. It is the datasets that the software mechanics interpret that are what would be at issue. If the customer types in the datasets then the software is fine and can interpret those datasets properly.
Yes, that is correct.
Reproducing the underlying logic defined by the rules through (compiled or not compiled) computer code should not normally be a violation of copyright law. However, using descriptive text (ie.
powers, feats, classes) and other proper nouns (ie.
Cleave, Eladrin Teifling) would be such a violation.
In order to actually do a 4E chargen/combat tracker/campaign-mgr you'd have to build the application with a separate user-editable dataset (serialize some datatables as xml). The dataset would not only define names, descriptive text, and flavor text...it would also have to contain a component defining the logical function of the object (the race, feat, power, etc) through some scripting language along the lines of DMGenie.
So in the app, a basic 4E (but ostensibly - as you'd argue in court - agnostic) framework is setup. Then the specific rules logic used in the game is consumed by the framework from the dataset (although some of the logic is going to be built into the framework, and specifics are left to the objects, like powers and race, in the dataset).
The app could be distributed with a dataset providing all the functionality of the core set of books and objects from the canonical 4E books, but done so using non-4E terms/names/nouns. So you call the eladrin race "celestial high elf" but have the race function exactly as the eladrin. As long as the flavor text doesn't mimic the text from the book, your not violating copyright. Remember the underlying logic of the rules is not copyrightable, only the text describing them. Fair use, really plays no role except to allow the end user to create personal datasets for personal use. Which would be the ostensible purpose and intention of the software...an important point to make not if but when you are taken to court for producing this app.
Further, and more heinously, the software author could leak a clandestine program which edits the provided dataset, replacing all the terms with canonical 4E terms and text...giving the end user a full 4E experience. Of course, the clandestine app would be illegal and one would not want to be tied to it.
Lastly, the bonus of such a design is that it would provide extensibility that everyone so desires in a chargen/combat-tracker. Having said all that, it would be a pretty time-consuming app to build.
Bottom line: you
should be ok to make such an app if you don't use key terms from the books. But that's a big
should. Ultimately its up to the decider-of-facts when the case goes to court. ...or at least that's what I think. I could be wrong. Use at your own peril.
EDIT: whatever you do, if you plan to make a piece of software to do 4E things, don't EVER sign the GSL agreement. Run from the GSL. GSL strictly forbids software. In making the software, your trying to avoid a copyright violation. Has nothing to do with GSL. GSL is irrelevant to this.