Illustration of keywords
x - current occurence
o - selected occurence
last _ _ _ o x _ _ _ _
last+ _ _ _ _ o _ _ _ _
last++ _ _ _ _ x o _ _ _
last- _ _ o _ x _ _ _ _
last-- _ o _ _ x _ _ _ _
last+1 _ _ _ _ x o _ _ _
last+2 _ _ _ _ x _ o _ _
last-1 _ _ o _ x _ _ _ _
last-2 _ o _ _ x _ _ _ _
this _ _ _ _ o _ _ _ _
this+ _ _ _ _ x o _ _ _
this++ _ _ _ _ x _ o _ _
this- _ _ _ o x _ _ _ _
this-- _ _ o _ x _ _ _ _
this+1 _ _ _ _ x o _ _ _
this+2 _ _ _ _ x _ o _ _
this-1 _ _ _ o x _ _ _ _
this-2 _ _ o _ x _ _ _ _
next _ _ _ _ x o _ _ _
next+ _ _ _ _ x _ o _ _
next++ _ _ _ _ x _ _ o _
next- _ _ _ _ o _ _ _ _
next-- _ _ _ o x _ _ _ _
next+1 _ _ _ _ x _ o _ _
next+2 _ _ _ _ x _ _ o _
next-1 _ _ _ _ o _ _ _ _
next-2 _ _ _ o x _ _ _ _