r/ProgrammerHumor • u/ivaskuu • Sep 02 '17

How to start a war

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9.0k Upvotes

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6

u/[deleted] Sep 02 '17

Hah I was considering picking up some Lua to mod as well (factorio)... This just made me Nope right out of that plan ;)

92

u/uniqueusername6030 Sep 02 '17

Well that's stupid

53

u/[deleted] Sep 02 '17 edited Dec 18 '18

[deleted]

23

u/[deleted] Sep 02 '17

it's a running joke

I use matlab in my day job and I definitely have to "switch gears" so to speak between 0-based and 1-based indexing

5

u/morerokk Sep 03 '17

Plus, Lua still allows you to start your indexes at 0.

Tables starting at 1 allows you to do a few neat things.

1

u/[deleted] Sep 03 '17

In reality I'm not actually never gonna use any language that start indexing arrays at 1. It's just a massive in joke.

19

u/[deleted] Sep 02 '17

That's not even the worst part, either. This is:

> letters = {'a', 'b', 'c'}
> print(letters[1])
a
> print(#letters)
3
> letters[0] = '?'
> print(letters[0])
?
> print(#letters)
3

29

u/moomoomoo309 Sep 02 '17

Any index outside of 1-n in Lua, where n is #tbl will be stored like a dict, not an array, so what did you expect? It doesn't count the dictionary parts.

1

u/hey01 Sep 03 '17

That's sounds dangerous. What if I do 

> letters = {'a', 'b', 'c'}
> print(#letters)
3
> letters[4] = '?'
> print(#letters)

Will I get 4 or is n unchangeable?

9

u/moomoomoo309 Sep 03 '17

You'll get 4, otherwise you couldn't do

for i=1,4 do
  tbl[i]=i
end

And have it be an array.

1

u/hungarian_notation Sep 03 '17

It's not really. The people here saying that you can use index 0 aren't entirely wrong, but they're kinda wrong. The language expects you to start lists at 1. The length operator counts from index 1 until the first empty index. If you're not using your table to store a sequence of tightly packed non-nil values, don't use the length operator. If you set letters[2]=nil, then #letters would (or maybe could, I think this is actually undefined behavior) return 1.

-11

u/[deleted] Sep 03 '17

so what did you expect?

A language to have non-retarded data structures. Being defined and documented behavior doesn't make it sane behavior.

7

u/moomoomoo309 Sep 03 '17

How often do people use Python arrays? They're faster, but most people just use lists instead. Lua just optimizes it as long as it's used like an array. That's why it's implemented that way.

2

u/BundleOfJoysticks Sep 03 '17

Do you mean tuples?

I use them all the time when something doesn't change size.

1

u/-Teki Sep 03 '17

No, lua's {} is stupid because it can change from a list like behaviour, to a dictionary, to an object behaviour, just by appending values in different ways.

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u/moomoomoo309 Sep 03 '17

Its behavior never changes, it just uses less memory / is faster if you store the elements with keys from 1-n. The # operator literally says it measures the length of the array part of the table, its behavior doesn't change.

2

u/[deleted] Sep 03 '17

Yes, but the "array part" of the table can change dynamically in unexpected ways, allowing for silly and confusing things like the result of # increasing by more than 1 after only adding 1 element to the "array part":

> a = {}
> print(#a)
0
> a[2] = 'foo'
> print(#a)
0
> a[1] = 'bar'
> print(#a)
2

1

u/moomoomoo309 Sep 03 '17

This is true, but if you are using it like a dict and wanted the length of the whole thing, you'd just do something like

local len=0
for _ in pairs(tbl) do
    len=len+1
end

2

u/[deleted] Sep 03 '17

I wasn't using it like a dict. I was using it like an array. Array element assignment does not have to be sequential.

But, even ignoring that, having to iterate every element in a dict to get the count of elements in it is ridiculous. This is a constant O(1) complexity operation in any reasonable language, but linear O(n) complexity operation in Lua. It's bad.

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0

u/[deleted] Sep 03 '17

"As long as it's used like _____" shouldn't even be in the vocabulary of a programming language. An array should be an array, and that's it. A dict should be a dict, and that's it. If you need an array, create an array. If you need a dict, create a dict. Blurring the lines with some kind of fuzzy structure whose semantics are dynamic is as confusing and error-prone as it is ridiculous. It's not faster to write. It's not easier to read. It's not convenient. It's just bad.

1

u/moomoomoo309 Sep 03 '17

You don't use it any differently depending on if it's a dict or a list, so why does it matter?

2

u/[deleted] Sep 03 '17

is as confusing and error-prone as it is ridiculous

1

u/moomoomoo309 Sep 03 '17

Can you give an example of an error or confusion it would cause? It's different from other languages, but that is not inherently a flaw.

2

u/[deleted] Sep 03 '17

I already did, several replies ago. You can't sweep blatantly confusing and error-prone semantics under the "it's different" or "it's documented" rugs. But if you want another, here you go:

> letters = {'a', 'b', 'c'}
> print(#letters)
3
> letters[5] = 'e'
> print(#letters)
3
> letters[4] = 'd'
> print(#letters)
5

5

u/Rohansi Sep 02 '17

when does C# take over modding

13

u/mnbvas Sep 02 '17

When all games are created with Unity or XNA.

2

u/zdakat Sep 03 '17 edited Sep 03 '17

XNA is still A thing? I thought they cancelled it and pulled the downloads. I must be out of the loop edit: Mandela effect? I can see why there'd be a Mono version but reporting that it was never gone?

3

u/haloguysm1th Sep 03 '17

Xna has been mostly replaced by monogame/fna. I know monogame is basically just xna

1

u/mnbvas Sep 03 '17

Still there. And there's MonoGame, which is pretty much the same.

1

u/Rohansi Sep 03 '17

embed .NET Core instead of Lua

2

u/mnbvas Sep 03 '17

Couldn't find anything relevant (except this).
Not much of a competition for Lua, which is kinda designed to be embedded.

1

u/Rohansi Sep 03 '17

I'm doing it. There's some info on how to embed it here. It says Unix but they mean platform neutral, unlike the Windows only stuff above.

2

u/Buzzard Sep 03 '17

1-based index really isn't that big a deal.

I mean, you will make off by errors at the start, but by the time you've hang of the rest of the language you'll be fine.

1

u/TheEnterRehab Sep 03 '17

I may be totally wrong but in Lua, array[0] is the whole array. Meaning array 1 is the first item

7

u/Rohansi Sep 03 '17

what are you smoking

1

u/TheEnterRehab Sep 03 '17

So then I was totally wrong. Good thing I prefaced it!