draw-tree

draw-tree.el

Draw tree structure of cons cells.

Ported to Emacs Lisp from Nils M Holm’s Scheme 9 from Empty Space’s Function Library (http://www.t3x.org/s9fes/draw-tree.scm.html) and its Common Lisp port written by CBaggers (https://github.com/cbaggers/draw-cons-tree).

Giulio Pietroiusti, 2022 Placed in the Public Domain.

Example:

  (draw-tree '((a) (b . c) (d e))) ;; ==> 
;; "
;; [o|o]---[o|o]---[o|/]
;;  |       |       |      
;; [o|/]    |      [o|o]---[o|/]
;;  |       |       |       |      
;;  a       |       d       e      
;;          |      
;;         [o|o]--- c      
;;          |      
;;          b      
;; "

See also:

• GNU Emacs Manual, Drawing Lists as Box Diagrams
• SICP, box-and-pointer notation
• amno1’s draw-cons-tree. (Analogous port, slightly different in that it inserts the result in the buffer as a side effect, rather than returning it. It allows to draw lines with unicode. Discovered after I wrote mine.)
• pair-tree.el