FOSS gamedev and creative worlds

I know there are functions called “on_put”, “allow_put”, “on_move”, “on_take”, etc. available for detached definitions; they are defined when calling minetest.create_detached_inventory.

I wonder if such functions are available for non-detached inventories as well. Especially player inventories.
I want to achieve that some slots of a player's inventory behave differently by only allow them to hold a particular item type, but no other item type.
I know this can be achieved for detached inventories by defining the allow_put function.

That's a good question. I haven't seen any of those functions for player inventories yet.
Open an issue on GitHub or code those functions because I see no other soulation.

This is possible for node inventories and for detached inventories, but not for player inventories. It would be nice.

For now your best bet is probably to create a detached inventory for each player or something. You'll probably have to be careful about persisting contents as I don't think they're kept in the world database (not completely sure of that one though). Unfortunately it'll also require changing player inventory formspecs. There's no built-in way to do that such that the change doesn't trample other mods' changes, so you'll either have to be incompatible with all other such mods or depend on a mod that provides a framework to coordinate changes.