Tcl vs perl - very old suspect documentation on porting. Here are some thoughts on the new Tk extension and how I think the organization of the commands looks. This is pretty much the same as tkperl5a5, with some cosmetic naming changes, and some more useful command name and usage changes. As this allows new to be inherited from a Window class.
Object references are now hashes rather than scalars and there is only ever one such per window.
1st extra arg is reference to the per-widget hash that serves as the perl object for the widget. Every time an XEvent a reference to a special class is placed in the widget hash.