I'm used to the illustration with a loom showing the melachos involved in weaving: Mesach (loading the string), Oseh Shtei Batei Nirim (loading the harness), Oreg (weaving), Potzea (un-weaving).
Knitting would certainly be weaving, and if you had to pull out a stitch that would be un-weaving; but are the two previous melachos involved?