canvas level query number of objects in specified canvas (most useful with {[gf/canvas_loadbang])} {[doc_h]} + {[doc_c]} + {[doc_i]} + {[doc_f]} + {[doc_o]} + {[doc_cc]} + {[doc_ii]} + {[doc_oo]} + 3 {[doc_m]} + 4 comments + floatbox + bangbox + {[loadbang]} + {[gf/canvas_count]} + {[doc_also]} + {[gf/canvas_index]} + {[gf/canvas_loadbang]} = 21