Factorio Forums

In JSON array types are expected to be something like this
and an empty array should be
but when getting the data.raw JSON dump by using the --dump-data flag fields that should be arrays and are empty are serialized as
which implies the field to be a map type of sorts and not an array.

Thanks for the report. Factorio doesn't actually support array types in data.raw. All types in data.raw are dictionaries with anything looking like an array being numeric-dictionaries.

{ value1, value2, ... } is actually short-hand for { 1=value1, 2=value2, 3=... }

Rseding91 wrote: ↑

Sat Oct 07, 2023 3:08 am

All types in data.raw are dictionaries with anything looking like an array being numeric-dictionaries

Interesting to know! The prototype docs just specified some types to be array[union] which is how I ended up at the assumption that they are arrays and that tripped when trying to deserialize "{}" as an array.

BrainGamer_ wrote: ↑

Sat Oct 07, 2023 7:09 am

Interesting to know! The prototype docs just specified some types to be array[union] which is how I ended up at the assumption that they are arrays and that tripped when trying to deserialize "{}" as an array.

We use the term "array" to mean "you don't need to care about the key values" but Lua itself only supports dictionaries (actually hash-maps under the hood).

Rseding91 wrote: ↑

Sat Oct 07, 2023 2:32 pm

We use the term "array" to mean "you don't need to care about the key values"

Makes sense. I still need to care about it in some way tho since the JSON changes "type" from being an array to a map when the "array" (or internal hash-map) is empty

I found a workaround but it is pretty hacky..

Why is it inconsistent though?
vs Please can we have empty flags in JSON dump as follows?

I went and looked into the "flags" case and found something interesting. Because Lua has no such concept as "dictionary" vs "array" when we parse it from Lua into C++ we have no idea what the type is when it's empty. To Lua, an empty table is an empty table - it's not a dictionary or array. So we have to pick one and when the Lua table is empty it defaults to "empty dictionary" on the C++ side. Along comes the "convert to Json" and it sees an empty dictionary and writes out {}.

To summarize: I don't see this ever changing. Unless Lua gets built in support for JSON (which i'm going to go out on a limb and say it never will).

Perhaps a more realistic solution would be writing everything as dictionaries when converting to JSON since that's actually closer to what Lua uses.

moon69 wrote: ↑

Fri Nov 10, 2023 3:54 pm

Code: Select all

"flags": 
      [
        "placeable-neutral",
        "player-creation"
      ],

The fun thing is that this is not the only valid representation for this! Since Lua basically does everything with HashMaps like Rseding said you can have the following:
or even better:
My solution to all of this in the end was to write a completely custom serde deserializer for this special type: https://github.com/fgardt/factorio-scan ... #L107-L154