On Apr 15, 2012 4:30 AM, "Joseph Rushton Wakeling" < joseph.wakel...@webdrake.net> wrote: > ... the compiler accepts it. Whether that's because it's acceptably pure, or because the compiler just doesn't detect this case of impurity, is another matter. The int k is certainly mutable from outside the scope of the function, so AFAICS it _should_ be disallowed.
As far as I understand pure includes the "hidden this parameter" so it is pure if when you call it on the same structure with the same arguments you always get the same results. Although that seams pretty useless in the optimization standpoint because the function can modify it's own object between calls.
