anchor.diff:  
   Calling this function NCOLLECT has at least two advantages:
   1. The N prefix reminds you that you must pass a fresh list
  -that isn't referenced anywhere else because of the destructive behavior
  +that isn't referenced anywhere else because of the destructive behavior;
   \(its tail will be modified the next time COLLECT or NCOLLECT is called).
   2. NCOllect starts the same as NCOnc.
   Other candidates would have been COLLECT-LIST (a bit long)
  
positive.code: 	   #:mappl
  	   #:mapplist
  	   #:mappcon
  
  	   #:for*
  	   #:step*
  
negative.code: 
  
  ;;; The following functions are analogous to MAPC/MAPCAR/MAPCAN
  ;;; and MAPL/MAPLIST/MAPCON, but for alists, plists and vectors.
  ;;;
  ;;; Also, with slightly different semantics,
  ;;; the MAPT* family of functions for mapping over integers.
  ;;;
  ;;; ┌───┬────────────────────────────┬────────┬───────────┬──────────┐
  ;;; │PKG│ Result accumulation method │ nil    │ list      │ nconc    │
  ;;; ├───┼────────────────────────────┼────────┼───────────┼──────────┤
  ;;; │   │         Values mapped over │        │           │          │
  ;;; │   ├----------------------------┤        │           │          │
  ;;; │CL │         elements of a list │ MAPC   │ MAPCAR    │ MAPCAN   │
  ;;; │CL │           conses of a list │ MAPL   │ MAPLIST   │ MAPCON   │
  ;;; │   │                            │        │           │          │
  ;;; │LL │ (key . value)s of an alist │ MAPAL  │ MAPALIST  │ MAPACON  │
  ;;; │LL │   (key value)s of an alist │ MAPAL* │ MAPALIST* │ MAPACON* │
  ;;; │LL │    (key value)s of a plist │ MAPPL  │ MAPPLIST  │ MAPPCON  │
  ;;; │LL │       elements of a vector │ MAPV   │ MAPVECTOR │ MAPVCON  │
  ;;; │   │                            │        │           │          │
  ;;; │LL │  integers from 0 below max │ MAPT   │ MAPTIMES  │ MAPTCON  │
  ;;; │LL │  As above, but no iter var │ MAPT*  │ MAPTIMES* │ MAPTCON* │
  ;;; └───┴────────────────────────────┴────────┴───────────┴──────────┘
  ;;;
  ;;; Note that the names of the new functions
  