TeachScheme! 2000

 Develop family trees: see pages 183-186
  [Popular topic in Utah. :)]

  from information in the world to Scheme data

  principle: one data definition per structure definition 

  DATA DEFINITION -- FIRST [use 'unknown instead of empty for base case]

  develop template -- FIRST

  now show how easily we can write functions on this:

  ;; is-in? : symbol family-tree -> boolean

  ;; count : family-tree -> number 
  
  ;; women-names : family-tree -> list-of-symbols

  and others 


  Web pages (lists of symbols and web pages)