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Possible bug with k and j

Open tjol opened this issue 3 years ago • 2 comments

Hi! I've been working on my own little Funge-98 interpreter and I've been testing against other interpreters, including of course cfunge. In testing the k instruction, I ran into a fair amount of undefined behaviour with different interpreters doing different reasonable things, but there's one thing that I think is a bug in cfunge in which iterating (k) the jump (j) instruction jumps too far.

To illustrate, this program:

332kjvvvvvvvvv          @
     123456789
     >>>>>>>>>  v
,a.,k7"2 * 3 = "<    v
vvvvvvvvvvvvvvvjk3::4<@
fedcba9876543210
>>>>>>>>>>>>>>>> v
@,a.,k7"4 * 3 = "<

prints

2 * 3 = 7 
4 * 3 = 14 

in cfunge, but

2 * 3 = 6 
4 * 3 = 12 

in every other interpreter I've tried (rcfunge, fbbi, ccbi, pyfunge).

If you're interested, here's my larger “edge cases of k’ test: https://github.com/tjol/rfunge/blob/f8a55e38be491e550e69d871a435004e8d58a176/tests/manual_tests/k.b98

[again, no pressure for you to actually spend any time on this if you have better things to do]

tjol avatar Aug 14 '21 07:08 tjol

I don't have time to look at this right now, but do you happen to know if this is something tested by the Mycology test suit?

VorpalBlade avatar Aug 23 '21 09:08 VorpalBlade

I don't have time to look at this right now, but do you happen to know if this is something tested by the Mycology test suit?

It's not.

tjol avatar Aug 23 '21 10:08 tjol