What is your question, precisely? Are you asking whether NaN exists, or whether it can be obtained as the result of accidental or voluntary computations? Yes, it does and it can. The sort of data structure that requires a total order for keys breaks down completely when the provided order is not a total order. … Read more
As discussed in the comments, I believe there are several aspects of the function template partial ordering algorithm that are unclear or not specified at all in the standard, and this shows in your example. To make things even more interesting, MSVC (I tested 12 and 14) rejects the call as ambiguous. I don’t think … Read more
You need to provide the rich comparison methods for ordering in Python 3, which are __lt__, __gt__, __le__, __ge__, __eq__, and __ne__. See also: PEP 207 — Rich Comparisons. __cmp__ is no longer used. More specifically, __lt__ takes self and other as arguments, and needs to return whether self is less than other. For example: … Read more
While Xeo gave a pretty good description in the comments, I will try to give a step-by-step explanation with a working example. First of all, the first sentence from the paragraph you quoted says: For each of the templates involved there is the original function type and the transformed function type. […] Hold on, what … Read more