This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Are you going to say you think it should be programmed to accept only 0xffff or 0XFFFF and not both? You can program a lexer to be case sensitive or case insensitive, or even to change case. So you can have OxFfFf, just as you can declare a float literal as 12.345f or 12.345F.