get a list of valid inventories for an entity

[sparr]

I don't currently have a way to figure out which indexes I can pass to entity.get_inventory() to get its inventories. I could do a bunch of digging and trial and error to produce a lookup table from entity type, probably, but that seems like a bad approach.

maybe entity.has_inventory(x)->bool or entity.inventories()->LuaInventory[]

[Sean Mirrsen]

I don't currently have a way to figure out which indexes I can pass to entity.get_inventory() to get its inventories. I could do a bunch of digging and trial and error to produce a lookup table from entity type, probably, but that seems like a bad approach.

maybe entity.has_inventory(x)->bool or entity.inventories()->LuaInventory[]

You need the list of defines.inventory - http://lua-api.factorio.com/0.13.0-prev ... .inventory

[sparr]

You need the list of defines.inventory - http://lua-api.factorio.com/0.13.0-prev ... .inventory

I already have that. What I need is to know which of those things go with which entities.

[Sean Mirrsen]

You need the list of defines.inventory - http://lua-api.factorio.com/0.13.0-prev ... .inventory

I already have that. What I need is to know which of those things go with which entities.

Uh, well most of the things on the list have pretty descriptive names. inventory_fuel goes for anything that has fuel, etc.

[sparr]

Yes, but how do I tell for an arbitrary entity whether it has fuel or not?

How do I tell which entities have a module inventory?

Etc.

[DaveMcW]

Code: Select all

/c game.player.print(game.entity_prototypes["steel-furnace"].energy_usage.type)

Error: LuaEntityPrototype doesn't contain key energy_usage.

Code: Select all

/c game.player.print(game.entity_prototypes["electric-furnace"].module_specification.module_slots)

Error: LuaEntityPrototype doesn't contain key module_specification.

[Sean Mirrsen]

Code: Select all

/c game.player.print(game.entity_prototypes["steel-furnace"].energy_usage.type)

Error: LuaEntityPrototype doesn't contain key energy_usage.

Code: Select all

/c game.player.print(game.entity_prototypes["electric-furnace"].module_specification.module_slots)

Error: LuaEntityPrototype doesn't contain key module_specification.

I'm still not quite certain why you would need to programmatically determine whether an entity has a fuel or module inventory. You could just check what entity it is and work from that, unless you're trying to add something that dynamically affects anything of a particular category. And yes, a lot of the raw data is not accessible from the scope of the Lua code run during the game.

Depending on what you're trying to do, you might make do with checking via can_insert, or just running through the whole table of inventory indices and seeing what returns nil.

[sparr]

So I should make the assumption that things with no energy_usage don't have a fuel inventory?

After I query the module_slots, how do I tell whether it's defines.inventory.furnace.modules or defines.inventory.lab.modules or some other modules inventory? (yes, those seem "obvious", but they really aren't when you get into the details of all the different entity types)

Basically you're asking me to trial-and-error a lookup table and function to get the inventory list for an entity. That should be part of the API.

[Adil]

The inventories are bound to type of entity, you can get type directly from entity.
Thus you only need to make a dictionary, maybe even programmatically, at the beginning of the mod, it'd be a dozen or two of entries but not completely out of possible.

[sparr]

It's not quite a dictionary; it would have to be a function with some logic. Furnaces all have input and output, but only some of them have fuel (see above re energy_usage).

I could write that function. It would probably be 95-99% accurate. That's not accurate enough.

[Adil]

Well, function would be 100% percent accurate if you add the relevant checks.

Also, where did you get that 'energy_usage'? Neither current nor next version expose that to runtime.

[sparr]

Depending on what you're trying to do, you might make do with checking via can_insert, or just running through the whole table of inventory indices and seeing what returns nil.

I filed a bug report alongside this request. Trying to access a nonexistent inventory index is currently a crash condition rather than returning nil. Someone on IRC pointed me towards pcall() to catch the error in lua and discard it, but that's really bad practice. Fortunately the bug report is already marked fixe din 0.13, so iterating through all indices and checking for nil is a viable approach next version.

Well, function would be 100% percent accurate if you add the relevant checks.

I do not trust that anyone, including myself, is able to list every one of the relevant checks. Together a few of us can probably get 99%, missing some corner cases that will show up in random situations with weird mods.

Also, where did you get that 'energy_usage'? Neither current nor next version expose that to runtime.

Just copied it from a post higher in this thread. This further proves my point. Coming up with the list of "relevant checks" is non-trivial.

[DaveMcW]

Also, where did you get that 'energy_usage'? Neither current nor next version expose that to runtime.

That's why this thread is in Modding interface requests.

[slindenau]

+1 for this request. Don't just throw an error if you're trying to access an inventory index that doesnt exist.
Either add a function to check if the inventory exists, or just return nil perhaps?

It is VERY bad practice that the end users have to determine based on the type of the entity what inventories it supports.
100% unmaintainable.

[sparr]

+1 for this request. Don't just throw an error if you're trying to access an inventory index that doesnt exist.
Either add a function to check if the inventory exists, or just return nil perhaps?

It is VERY bad practice that the end users have to determine based on the type of the entity what inventories it supports.
100% unmaintainable.

Already confirmed in the bug report forum that get_inventory() will return nil instead of error in 0.13

[Rseding91]

+1 for this request. Don't just throw an error if you're trying to access an inventory index that doesnt exist.
Either add a function to check if the inventory exists, or just return nil perhaps?

It is VERY bad practice that the end users have to determine based on the type of the entity what inventories it supports.
100% unmaintainable.

Already confirmed in the bug report forum that get_inventory() will return nil instead of error in 0.13

Indeed. It made no sense to throw an error since multiple entities might have or won't have an inventory and there was no way to know if it did before calling "get".

if anyone comes across other methods that throw errors when it doesn't make sense feel free to make bug reports about them. Specifically something is meant to throw an error when it's easily possible to tell if you should be calling that method to begin with. Something like trying to set a recipe on a rock for instance would be an error - you should only ever be calling that on an assembling machine type entity. Trying to get the electric energy of an entity however shouldn't generate an error because there's no good way to tell if an entity actually has electric power without just calling the get property.