Re: size-of instance?

[bill@cambridge.apple.com (Bill St. Clair)]

At 12:00 PM 5/18/95, Arnoud Verdwaald wrote:

>Is this code really okay? It gives me weird results (on this Mac LC475 at
>least):
>
>? (meter-consing (cons 1 2))
>Consed -368 bytes

I made this happen once in 5 tries if I used it when *compile-definitions*
was false. This doesn't surprise me since the evaluator conses may
cons up some stuff before the first call to GC.

>(1 . 2)
>? (let ((result-list nil))
>    (dotimes (i 100)
>      (setf result-list (cons i result-list)))
>    (meter-consing result-list))
>Consed 0 bytes
>(99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76
>75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51
>50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26
>25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0)

Your code does its consing outside the dynamic extent of the meter-consing
form. Hence, it is correctly reporting that no consing took place there.