how to hide file extension on mac os x?

Question

say we have a file "a.txt.www". Can I hide abc with objective c? I can hide "a.txt" to "a",and I can also hide "a.abc" to "a", but I can not hide "a.txt.www" to "a.txt"

Answer 1

A file only has one extension (which can be hidden via the "Hide Extension" checkbox in the Finder's "Get Info" window).

The current version of MacOS and the Finder do not know anything about the concept of multiple file extensions ("a.txt.www or "a.rtf.jet", where the filename is just "a").