return uniqu text given kei modifi param modifi modifi translat corrispond text kei code modifi text modifi buffer buf buffer modifi input event shift mask buf append shift modifi append modifi joiner modifi input event ctrl mask buf append ctrl modifi append modifi joiner modifi input event meta mask buf append meta modifi append modifi joiner modifi input event alt mask buf append alt modifi append modifi joiner modifi input event alt graph mask buf append alt graph modifi append modifi joiner buf 