facts-db/cl-lessp/README.md

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• Hash : 9961ed5e
  Author : Thomas de Grivel
  Date : 2022-11-18T19:40:00
  

  generic order predicate in Common Lisp

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 (/ (fruit-price b) (fruit-weight b))))

  (orange (make-fruit) :price 4.5 :weight 1000))

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• README.md

• lessp - Generic order predicate
  ===============================
  
  Compare anything
  ----------------
  
  (lessp 'a 'b)
  => T
  
  (lessp 'a "a")
  => T
  
  (lessp '(a b 1) '(a b 2))
  => T
  
  Your own order
  --------------
  
  (defstruct fruit weight price)
  
  (defmethod lessp ((a fruit) (b fruit))
    (lessp (/ (fruit-price a) (fruit-weight a))
    	 (/ (fruit-price b) (fruit-weight b))))
  
  (let ((apple (make-fruit :price 0.3 :weight 100))
        (orange (make-fruit) :price 4.5 :weight 1000))
    (lessp apple orange))
  
  => T
  
  Contribute
  ----------
  
  This project welcomes LESSP methods for types that have an
  [atomic type specifier][1], with an emphasis on speed and functional
  correctness.
  
  [1]: http://www.lispworks.com/documentation/lw51/CLHS/Body/04_bc.htm
  
  To submit contributions, just fork the project and submit a pull
  request.
  
  Licence
  -------
  
  lessp - Generic order predicate
  
  Copyright 2011-2022 Thomas de Grivel <thodg@kmx.io>
  
  Permission is hereby granted to use this software granted
  the above copyright notice and this permission paragraph
  are included in all copies and substantial portions of this
  software.
  
  THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF
  PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE
  AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF
  THIS SOFTWARE.
  

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