FOSS gamedev and creative worlds

Posted: **Fri Jun 10, 2016 20:35**

I am working on a command for my mod, that update a node in the location specified through a chatcommand to the block specified. This should be pretty simple, but I'm trying to write it in a way that players don't get all the weird errors and get confused (like me), but instead get simple error messages through the chat.

I'm having two issues. When I run /update default:dirt 125 1.5 -26.2, I get "attempt to index a nil value," at line 39.

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: local item_string_type = minetest.registered_items[node].type -- item string type

This line gets the type (node, craftitem, tool) for an if statement that confirms the type is node.

When I run the command the other way around, /update 125 1.5 -26.2 default:dirt, I get and error in the chat saying:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: 2016-06-10 13:14:11: ERROR[Server]: Map::setNode(): Not allowing to place CONTENT_IGNORE while trying to replace "air" at (125,2,-26) (block (7,0,-2))

The /update functions accepts two values, name and param. player is then set from param, and node, p is set from param. Then I set item_string_type, for the if statement.

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: -- variables local player = minetest.get_player_by_name(name) -- player name local node, p = string.match(param, "^([^ ]+) *(.*)$") local p = minetest.string_to_pos(p) local item_string_type = minetest.registered_items[node].type -- item string type

+ The full function called by /update:

You can browse the code of the whole mod here, though functions.lua is missing several small fixes that I have not committed yet because of the above issues.

Posted: **Fri Jun 10, 2016 22:39**

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: minetest.set_node(p, {name = param})

You probably meant to use `node` instead of `param` here.

From your code, it seems you get (for example) `default:dirt 1,2,3` as param which you split into `node` ("[^ ]+" pattern), and `p` (".*" pattern).

A few more tips:

`string.match` may return nil if the string does not match the pattern, so you should take that into account before passing to `string_to_pos`.
As an extension to the above, `string_to_pos` may also return nil if it cannot parse the string as a position.
You seem to compare `registered_nodes[node]` to both nil and a string. IIRC, registered_nodes[node] always returns a table thanks to metatables, so you should use another check to see if the node exists. Probably `rawget(minetest.registered_nodes, node) ~= nil`.
You also seem to compare strings to numbers in `if p.x=="" ...`. This would not crash, but it will always return false.

Posted: **Sat Jun 11, 2016 00:48**

Thanks!

The function now looks like this, and seems to work fine:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: -- Update Block function servertools.update_node(name, param) -- variables local player = minetest.get_player_by_name(name) -- player name local node, p = string.match(param, "^([^ ]+) *(.*)$") local p = minetest.string_to_pos(p) -- confirm node param if minetest.registered_items[node] == nil then minetest.chat_send_player(name, "Please enter a valid item string.") --print to chat minetest.log("action", "[ServerTools] "..name.." tried to update a node with an invalid item string.") --print to log else local item_string_type = minetest.registered_items[node].type -- item string type -- make sure item string is not a craftitem or tool if item_string_type == "tool" or item_string_type == "craft" then minetest.chat_send_player(name, "Item string is of invalid type "..item_string_type..".") --print to chat minetest.log("action", "[ServerTools] "..name.." tried to update to "..item_string_type..".") --print to log else if p == nil or p == "" then minetest.chat_send_player(name, "Please enter valid coordinates.") --print to chat minetest.log("action", "[ServerTools] "..name.." tried to update a node with invalid coordinates.") --print to log return end -- confirm position params if p.x == nil or p.y == nil or p.y == nil or p.z == nil then -- print error to chat and log minetest.chat_send_player(name, "Please enter valid coordinates.") -- print to chat minetest.log("action", "[ServerTools] "..name.." tried to update a node with invalid coordinates.") --print to log else -- update node minetest.set_node(p, {name = node}) end end end end

If I missed something, I always appreciate knowing. PS: Check out the mod that this is for, servertools (not quite ready to post on the forums yet).

FOSS gamedev and creative worlds

[solved] set_node error

[solved] set_node error

Re: Errors... help!

Re: Errors... help!