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[notarctic]

gml once gave me an error for a ' i had in a commented line

[Orpheon]

Yeah, gml parsing of comments is sometimes really strange.

Code: [Select]

/*hhh/*/Haven't tested, but if I recall correctly this breaks.

[Vindicator]

I still can't get over this from a few months ago. I recently re-discovered the problem and looked more into it, but it turns out it's not really GML's fault;

Code: [Select]

GML:
(-120) mod 360 == -120

Python:
(-120) % 360 == 240

Wolfram Alpha:
(-120) % 360 == 240

Google:
(-120) % 360 == 240

So, the answer I was looking for is definitely 240, because I was working with angles, and negatives would break lots of things. However, that's also what I expected to be the proper implementation of modulo.

I had been laughing at GML for the incorrect implementation of modulo, but to my suprise I recently discovered Java does the same thing as well!

Code: [Select]

Java:
(-120) % 360 == -120
Curious.

As it turns out, the implementation of modulo isn't exactly universally accepted.
http://en.wikipedia.org/wiki/Modulo_operation#Common_pitfalls

wat.

Anyway, I wrote my own modulus for the time being.

Code: [Select]

return argument0 - argument1 * floor(argument0 / argument1);

[Phantom Brave]

((x mod y) + y) mod y

[MedO]

(x + y) mod y

ftfy

[ajf]

(x + y) mod y

ftfy

this only works where -y < x < y, but not for -2y < x < 2y

[Phantom Brave]

(x + y) mod y

ftfy

not according to ALGEBRA

[ajf]

((x mod y) + y) mod y

x = -195
y = 10

((-200 mod 10) + 10) mod 10
(-5 + 10) mod 10
5 mod 10
5

(x + y) mod y

ftfy

x = -195
y = 10

(-195 + 10) mod 10
-185 mod 10
-5

wareya's right and we're both wrong?

[MedO]

Augh, you're right of course.

[Ignis]

does gml use "mod" as the same thing as % in java (gives remainder of two numbers)

[Vindicator]

does gml use "mod" as the same thing as % in java (gives remainder of two numbers)

Yeah, that's what modulus does. It's just that GML and java take the sign of the dividend when doing the calculation so its results are different from other accepted implementations of modulo division (Python, C).

[Ignis]

I see, thanks.

[ajf]

21:12 - (ajf): so guess what
21:13 - (ajf): if your extension defines a function in its manifest
21:13 - (ajf): which its GML lacks
21:13 - (ajf): ...GM will not moan
21:13 - (ajf): just silently fail
21:13 - (ajf): Thanks Overmars

[Orpheon]

21:12 - (ajf): so guess what
21:13 - (ajf): if your extension defines a function in its manifest
21:13 - (ajf): which its GML lacks
21:13 - (ajf): ...GM will not moan
21:13 - (ajf): just silently fail
21:13 - (ajf): Thanks Overmars

Manifest?

[ajf]

21:12 - (ajf): so guess what
21:13 - (ajf): if your extension defines a function in its manifest
21:13 - (ajf): which its GML lacks
21:13 - (ajf): ...GM will not moan
21:13 - (ajf): just silently fail
21:13 - (ajf): Thanks Overmars

Manifest?

I mean, in Extension Maker.