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<blockquote data-quote="GSHamster" data-source="post: 6179524" data-attributes="member: 20187">I may have glossed over some points that I should have included. Here are some additional thoughts.For subtype polymorphism to work correctly, a subclass cannot contradict the base class. This is called the Liskov Substitution Principle. If it does contradict, you will end up with situations where the subclass is an imperfect substitute, and may have conflicts.For example, let's you define a base Cleric class that can wear heavy armor. You cannot then create a subclass Priest which cannot wear heavy armor, only robes. That would violate Liskov. You can go the other way around, and have Priest be the base class, and Cleric the subclass which can wear heavy armor in addition to robes.Again, we go back to the Psionist. Psionist inheriting from Mage contradicts the Mage being able to cast arcane spells, and is a violation of Liskov. If it was up to me, given the current class structure in Next, I would have Psionist inherit from Rogue instead. We could justify Sneak Attack by saying that all Psionists have a touch of precognition and telepathy that unconsciously aids them in combat. Sneak attack could either follow the basic rogue rules, or be tweaked to something like &quot;gains Sneak Attack when fighting intelligent opponents&quot;, reinforcing the idea that the psionist is picking up some of her opponent's thoughts.</blockquote>

[QUOTE="GSHamster, post: 6179524, member: 20187"] I may have glossed over some points that I should have included. Here are some additional thoughts. For subtype polymorphism to work correctly, a subclass cannot contradict the base class. This is called the [i]Liskov Substitution Principle[/i]. If it does contradict, you will end up with situations where the subclass is an imperfect substitute, and may have conflicts. For example, let's you define a base Cleric class that can wear heavy armor. You cannot then create a subclass Priest which cannot wear heavy armor, only robes. That would violate Liskov. You can go the other way around, and have Priest be the base class, and Cleric the subclass which can wear heavy armor in addition to robes. Again, we go back to the Psionist. Psionist inheriting from Mage contradicts the Mage being able to cast arcane spells, and is a violation of Liskov. If it was up to me, given the current class structure in Next, I would have Psionist inherit from Rogue instead. We could justify Sneak Attack by saying that all Psionists have a touch of precognition and telepathy that unconsciously aids them in combat. Sneak attack could either follow the basic rogue rules, or be tweaked to something like "gains Sneak Attack when fighting intelligent opponents", reinforcing the idea that the psionist is picking up some of her opponent's thoughts. [/QUOTE]

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