It's doubtful that "convert it to lower case" (as documented for the function you pointed to) actually means anything in this day and age, what with Unicode and

It's doubtful that "convert it to lower case" (as documented for the function you pointed to) actually means anything in this day and age, what with Unicode and all... Though, looking at the code for "normalize" it appears to only support ASCII. That's even worse since now "lowercase" doesn't even apply uniformly if your identifiers have non-ASCII characters in them[0]. Doing a general normalization (as in Unicode) would probably also be bad, but for different reasons: You probably don't want the validity of programs to depend on the current locale of the machine you're compiling on. (See e.g. the "Turkish I" problem.) In short: Case-insensitive identifiers[1] are a terrible, terrible idea. [0] Not generally a good idea, but it happens and there are legitimate cases for it. [1] Or, rather, "doing anything non-trivial to identifiers before lookup", I suppose.