"Keys Must Be Strings"

Feature Requests Studio Features
#21

That makes sense because Part:Destroy() is a function.

OwnedProductsSet = { [3453255] = true } is a declaration.

I would expect it to be wrapped in a function() … end

#22

oh, in tables you can define string keys like declarations, so

{a=1, b=2, c=3}

is the same as

{["a"]=1, ["b"]=2, ["c"]=3}

OwnedProductsSet is inside a table. {OwnedProductsSet = { [3453255] = true }}

#23

No.

Assignment is not a function.

For example:

print(p = 5)

Gives:

blob.png

So I don’t understand how you can invoke an assignment like this:

blob.png

You should need to do this:

print(function() p = 5 end)

Giving a function object back:

blob.png

#24

It’s the assignment of an index within the table.

t={p=5}

is the same as

t={}
t.p=5
#25

This shouldn’t be invokable either.

print(t={p=5}) errors

#26

Note that Quenty’s example is just a BindableFunction which has the function connection missing.

e.g. he calls the bindablefunction but he didn’t connect a function to it yet. Probably for the sake of it being an example.

This is proper use of a BindableFunction:

Function = Instance.new("BindableFunction")

Function.OnInvoke = function(a,b,c) print(a,b,c) end

Function:Invoke(1,2,3) -- prints "1 2 3"

You can pass any arguments you want, also tables.

1 Like
#27

Are you being confused by the whitespace? All whitespace is the same in Lua, so Quenty’s code is the same as this:

Function:Invoke({OwnedProductsSet = { [3453255] = true }})
#28

We write it to a base 128 character instead of a base 256 character, and then escape.

\0
<
>
"
'
&

However, sometimes, very very rarely, when you save data, and shutdown the server, then reopen the server, and try to load the data, it’s corrupted, but somehow the extract function still manages to read it? Very rarely.

So there’s probably some combination of characters that datastore doesn’t like.

#29

Last I checked, datastores don’t like characters above 127, because somewhere along the line the data gets treated as unicode.

I’ve learned to just base64 everything.

#30

Quenty’s code is more like print({p=5})

#31

Do you know for a fact that the data gets treated as unicode?

#32

No I understand now.

I don’t use BindableFunctions very much and I didn’t understand that they had a function pointer assigned with OnInvoke and then Invoke is just a list of arguments. Does {OwnedProductsSet = { [3453255] = true }} evaluate the same as OwnedProductsSet? I know C has this behavior but I don’t depend on it when using other languages.

#33

It’s a table where OwnedProductsSet is a key in the table, and the associated value is another table where numerical index 3453255 is true.

#34

Last I checked was back when datastores first came out, so I don’t know if it has since been fixed. What I do remember is that the process of storing and loading data is a stupid mess, involving several layers of encoding.

If I remember correctly: During data retrieval, the data is requested from the cloud, and the cloud sends a response in JSON format. That gets decoded into some content, which contains the datastore data in JSON format (yes, two layers of JSON). Finally, that is decoded into the actual raw data. At some point in this process (probably the server response) the data is treated as unicode.

I have no idea if any of this is true anymore. I’d have to test it all over again, but I’m not interested enough to do it at the moment. It involves enabling studio access to datastores, and some Fiddling and/or Wiresharking.

I’m not sure what you mean. Curly-brackets in Lua always means a table is being created, and nothing else. So the code {OwnedProductsSet = {[3453255] = true}} creates a table that contains a “OwnedProductsSet” key, whose value is another table.

Consider the following code:

local data = {}
data.OwnedProductsSet = "foobar"
lookAtStuff(data)

This has the same result as:

local data = {OwnedProductsSet = "foobar"}
lookAtStuff(data)

Which has the same result as:

lookAtStuff({OwnedProductsSet = "foobar"})

And the function being called might look like:

function lookAtStuff(stuff)
    print(stuff.OwnedProductsSet) --> foobar
end
#35

In C, this returns 1

blob.png

And this returns 0

blob.png

This is because the assignment operator = has the behavior of returning the data assigned as an rvalue.

Lua seems not to work like this.

if (p = true == true) then print(1) end

Produces an error. So I conclude that the answer to my question is that assignment in Lua returns nothing.

1 Like
#36

This suggestion should be applied to RemoteEvent/RemoteFunction objects as well.

#37

We’ve updated the message to this, which has a few more details:

15:58:22.372 - Workspace.Script:2: bad argument to 'Invoke' (cannot convert mixed or non-array tables: keys must be strings)

:slight_smile:

2 Likes
#38

What if instead you let keys be ints?

#39

The keys can either be strings or consecutive integers (1,2,3,4,etc.). Anything else will throw an error.

#40

VolcanoINC was right–we also support arrays.

We’re currently serializing into a map with keys as strings, a type used in around 500 places in the code. Right now I’m not comfortable refactoring input, marketplace, datastore, players, replication, the primary class system, plugins, chat, studio’s explorer and input, intellesense, asset loading, and primary analytics. A change of this size would take the whole summer and would introduce regressions in ROBLOX’s whole codebase. As an intern, this is not a good first-week project.

I’ve filed a new bug report for this.

If there is a specific use-case that you specifically want to use mixed tables, please file a request in this forum, and it will also be added to our internal list. These changes can be done quicker than fixing the whole system. Thanks!

1 Like