Provide GUI context (menu or tab) from gtkbuilder files for mnemonic conflict checks

Hallo Intltool-devs

This is a request for a new feature that was brought up in this e-mail thread on the gnome-i18n list http://mail.gnome.org/archives/gnome-i18n/2012-January/msg00021.html.

The point is that when translators translate UI strings that have key accelerators (menmonics) in them, we have no way to check whether the key accelerator we assign will conflict with another one e.g. in the same menu (not without opening the program and manually looking for conflicts, which may include compiling the program from source if it is the development version).

One possible solution to this is for intltool to automatically add a comment about which accelerator group the string is in. Having such comments would allow tools such as pofilter (http://translate.sourceforge.net/wiki/toolkit/pofilter) or poabc (https://launchpad.net/pyg3t) to give a warning if there are conflicting accelerator keys in the group.

I think the groups should be formed by which window, menu line, menu or tab (more?) the ui string is in (in a prioritized order), so maybe it is possible to implement this by keeping track of the id of the last window, menu line, menu or tab that a ui string is located under in the GtkBuilder xml tree.

Two obvious caveats are:
1) This will off course only help us if the layout is indeed in a GtkBuilder file (I don't know how many projects do it otherwise).
2) I don't think this approach will easily include the accelerators for standard GtkButtons like "Open", "Close", "Quit" etc. so the translators will still need to keep track of those, but that is still a lot easier. (One might imagine someway of manually adding that information for the checking tools but that is in the details.)

Regards Kenneth (TLE)