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Encoding:
Prolog Source  |  1987-10-21  |  380 b   |  24 lines
  1. /* BAKTRAK.PRO */
  2.  
  3. /* Uses backtracking to print
  4.    all solutions to a query */
  5.  
  6. PREDICATES
  7.  
  8.   country(symbol)
  9.   print_countries
  10.  
  11. CLAUSES
  12.  
  13.   country(england).
  14.   country(france).
  15.   country(germany).
  16.   country(denmark).
  17.  
  18.   print_countries :- country(X),
  19.                      write(X),
  20.                      nl,
  21.                      fail.
  22.  
  23.   print_countries.
  24.