Topic: DosLib: Explanation of "dos_difference"

[Peter2]

The help for dos_difference gives these examples:

Code - Auto/Visual Lisp: [Select]

1. Command: (dos_difference 10)
2. -10
3.  
4. Command: (dos_difference 10 3 5 8)
5. -6
6.  
7. Command: (dos_difference '(10 3 5 8))
8. 2
9.  
10. Command: (dos_difference '(10 3) '(2 7))
11. (8 -4)

Example b) is the only one which I understand: 10-3-5-8=-6

But for the other ones I don't see the maths behind it. Who can explain?

Thanks!

[Marc'Antonio Alessi]

Maybe:

Code: [Select]

(dos_difference 10) > (dos_difference 0 10) > -10

(dos_difference '(10 3) '(2 7)) > ((10 - 2) (3 - 7)) >  (8 -4)

(dos_difference '(10 3 5 8)) > ?

[roy_043]

Apparently, if the parameters are lists they should have no more than 3 items:

Code: [Select]

: (dos_difference '(1 2 3 4) '(10 3 5 8))
nil
: (dos_difference '(1 2 3) '(10 3 5))
(-9 -1 -2)
: (dos_difference '(10 3 5))
2
: (dos_difference '(10 3 5 1000))
2


[Peter2]

Great, thanks.

Has one of you contact to the devs on Github to report? Or should I report it?

[Peter2]

I talked with Dale at Github, and it seem to be the strange behaviour of the Lisp Interpreter, already described here;
https://wiki.mcneel.com/doslib/dos_strformatdate

It seems that ..
- it occurs (only?) in lists with 4 entries
- it can be worked-around with more than 4 entries or
- defining the first value in first list as real and not as integer.

Here my tests:

Code - Auto/Visual Lisp: [Select]

1. Befehl: (dos_difference '(10 3) '(2 7))
2. (8 -4)
3.  
4. Befehl: (dos_difference '(10 3 20 30) '(2 7 5 6))
5. nil
6.  
7. Befehl: (dos_difference '(10.0 3 20 30) '(2 7 5 6))
8. (8 -4 15 24)
9.  
10. Befehl: (dos_difference '(10 3 20 30 8 9 10 11) '(2 7 5 6))
11. nil
12.  
13. Befehl: (dos_difference '(10 3 20 30 8 9 10 11) '(2 7 5 6 2 3 4 5))
14. (8 -4 15 24 6 6 6 6)
15.  
16. Befehl: (dos_difference '(10 3 20) '(2 7))
17. nil
18.  
19. Befehl: (dos_difference '(10 3 20 30 8 9 10) '(2 7 5 6 2 3 4 ))
20. (8 -4 15 24 6 6 6)
21.  
22. Befehl: (dos_difference '(10 3 20 30 8 9) '(2 7 5 6 2 3))
23. (8 -4 15 24 6 6)
24.  
25. Befehl: (dos_difference '(10 3 20 30 8 ) '(2 7 5 6 2 ))
26. (8 -4 15 24 6)
27.  
28. Befehl: (dos_difference '(10 3 20 30 ) '(2 7 5 6  ))
29. nil
30.  
31. Befehl: (dos_difference '(10.0 3 20 30 ) '(2 7 5 6  ))
32. (8 -4 15 24)
33.  
34. Befehl: (dos_difference '(10.5 3 20 30 ) '(2 7 5 6  ))
35. (8.5 -4 15 24)
36.  
37. Befehl: (dos_difference '(10 3 20 30 ) '(2 7 5.0 6  ))
38. nil
39.  
40. Befehl: (dos_difference '(10 3.0 20 30 ) '(2 7 5.0 6  ))
41. nil
42.  
43. Befehl: (dos_difference '(10.0 3 20 30 ) '(2 7 5.0 6  ))
44. (8 -4 15 24)
45.  
46. Befehl: (dos_difference '(10.0 3 20 30 ) '(2 7 5 6  ))
47. (8 -4 15 24)
48.  
49. Befehl: (dos_difference '(10 3 20 30 ) '(2.0 7 5 6  ))
50. nil
51.  
52. Befehl: (dos_difference '(10.0 3 20 30 ) '(2 7 5 6  ))
53. (8 -4 15 24)
54.