Thanks for the reminder. I had come across cppitertools before and wanted to explore it and then totally forgot. Not sure why you got downvoted here, have tried to compensate.

BTW your handle rung a bell. I was wracking my brain to remember where have I heard of it before, then finally, oh yes MacSTL. It really deserves more love. Have not used it, but sure browsed the code.

Thanks for this - hadn't picked up on it.