;;;; TASK II: SELECT -- PICK (DEMO)  
  
  i i i i i i i       ooooo    o        ooooooo   ooooo   ooooo
  I I I I I I I      8     8   8           8     8     o  8    8
  I  \ `+' /  I      8         8           8     8        8    8
   \  `-+-'  /       8         8           8      ooooo   8oooo
    `-__|__-'        8         8           8           8  8
        |            8     o   8           8     o     8  8
  ------+------       ooooo    8oooooo  ooo8ooo   ooooo   8

Welcome to GNU CLISP 2.49 (2010-07-07) <http://clisp.cons.org/>

Copyright (c) Bruno Haible, Michael Stoll 1992, 1993
Copyright (c) Bruno Haible, Marcus Daniels 1994-1997
Copyright (c) Bruno Haible, Pierpaolo Bernardi, Sam Steingold 1998
Copyright (c) Bruno Haible, Sam Steingold 1999-2000
Copyright (c) Sam Steingold, Bruno Haible 2001-2010

Type :h and hit Enter for context help.

[1]> ( load "lp.l")
;; Loading file lp.l ...
;; Loaded file lp.l
T
[2]> (trace select)
;; Tracing function SELECT.
(SELECT)
[3]> ( select 2 '(1 2 3 4) )
1. Trace: (SELECT '2 '(1 2 3 4))
2. Trace: (SELECT '1 '(2 3 4))
3. Trace: (SELECT '0 '(3 4))
3. Trace: SELECT ==> 3
2. Trace: SELECT ==> 3
1. Trace: SELECT ==> 3
3
[4]> ( select 2 '(1 2 4) )
1. Trace: (SELECT '2 '(1 2 4))
2. Trace: (SELECT '1 '(2 4))
3. Trace: (SELECT '0 '(4))
3. Trace: SELECT ==> 4
2. Trace: SELECT ==> 4
1. Trace: SELECT ==> 4
4
[5]> ( select 4 '(1 2 3 4 5 6 7 8) )
1. Trace: (SELECT '4 '(1 2 3 4 5 6 7 8))
2. Trace: (SELECT '3 '(2 3 4 5 6 7 8))
3. Trace: (SELECT '2 '(3 4 5 6 7 8))
4. Trace: (SELECT '1 '(4 5 6 7 8))
5. Trace: (SELECT '0 '(5 6 7 8))
5. Trace: SELECT ==> 5
4. Trace: SELECT ==> 5
3. Trace: SELECT ==> 5
2. Trace: SELECT ==> 5
1. Trace: SELECT ==> 5
5
[6]> (untrace select)
(SELECT)
[7]> (pick '(2 4 6 8 10))
8
[8]> (pick '(1 2 3 4 5 6))
2
[9]> (pick '(3))
3
[10]> (pick '(2 4 6 8 10))
6
[11]> (pick '(1 2 3 4 5 6))
1
[12]> (bye)
Bye.