Well, of course the author of the compiler could argue that the compiler is bug-free, and all behavior is intentional. While this would be laughable in most cas

Well, of course the author of the compiler could argue that the compiler is bug-free, and all behavior is intentional. While this would be laughable in most cases, there is no 'hard evidence' that this is not the case. A standard is needed in some cases where there is no 'obvious' behavior. I think this is the way that the 'Ruby standard' is defined, by a reference implementation which is assumed to be bug-free. About the interpretation of the standard: this is probably true, but this kind of technical documents is meant to be mono-interpretable, if you know what I mean. Ultimately there might be a few limitations which you don't encounter in practice (if you give your variables names of more than 4k characters, I doubt if it will compile), so you might argue this is an 'interpretation of the standard'. I would argue that in such a case technically, the compiler doesn't comply with the standard, but for all purposes and intents, it does (and so, in practice no one would doubt that the compiler complies to the standard).