Add //ngroups, which lists the groups a given node is a member of

CHANGELOG.md

@@ -9,6 +9,7 @@ Note to self: See the bottom of this file for the release template text.
 - Added a (rather nuclear) fix (attempt 4) at finally exterminating all zombie region marker walls forever
 	- This is not a hotfix to avoid endless small releases fixing the bug, as it's clear it's much more difficult to fix on all systems than initially expected
 - Added [`//nodeapply`](https://worldeditadditions.mooncarrot.space/Reference/#nodeapply), a generalisation of [`//airapply`](https://worldeditadditions.mooncarrot.space/Reference/#airapply) that works with a defined list of nodes. Check out [the reference](https://worldeditadditions.mooncarrot.space/Reference/#nodeapply) - it has some cool tricks to it! (thanks for suggesting, @kliv91 from the Discord server!)
+- Added [`//ngroups`](https://worldeditadditions.mooncarrot.space/Reference/#ngroups), which lists the groups that a given node is a member of. Useful when paired with [`//nodeapply`](https://worldeditadditions.mooncarrot.space/Reference/#nodeapply)!
 
 
 ## v1.14.5: The multipoint update, hotfix 5 (1st August 2023)

Chat-Command-Reference.md

@@ -1401,6 +1401,42 @@ This command is intended for development and modding. You will not normally need
 ```
 
 
+### `//ngroups <node_name> [v[erbose]]`
+Lists the groups that a given node is a member of. For example:
+
+```weacmd
+//ngroups sand
+```
+
+Might return:
+
+```
+default:sand ∈ sand crumbly falling_node
+```
+
+Groups in Minetest can also have a numerical value greater than 0. Append `v` or `verbose` to see those values:
+
+```weacmd
+//ngroups sand v
+//ngroups sand verbose
+```
+
+...both of the above might produce an output like this:
+
+```
+default:sand ∈ sand=1 crumbly=3 falling_node=1
+```
+
+Finally, the customary misc examples:
+
+```weacmd
+//ngroups sand
+//ngroups bakedclay:orange v
+//ngroups cactus
+//ngroups default:dry_shrub v
+```
+
+
 ## Extras
 <!--
 ███████ ██   ██ ████████ ██████   █████  ███████

worldeditadditions_commands/commands/nodes/init.lua

@@ -0,0 +1,11 @@
+-- ███    ██  ██████  ██████  ███████ ███████
+-- ████   ██ ██    ██ ██   ██ ██      ██     
+-- ██ ██  ██ ██    ██ ██   ██ █████   ███████
+-- ██  ██ ██ ██    ██ ██   ██ ██           ██
+-- ██   ████  ██████  ██████  ███████ ███████
+
+-- Commands that operate on information about nodes, and NOT on the world itself..
+
+local we_cmdpath = worldeditadditions_commands.modpath .. "/commands/nodes/"
+
+dofile(we_cmdpath .. "ngroups.lua")

worldeditadditions_commands/commands/nodes/ngroups.lua

@@ -0,0 +1,52 @@
+local wea_c = worldeditadditions_core
+local Vector3 = wea_c.Vector3
+
+
+-- ███    ██  ██████  ██████   ██████  ██    ██ ██████  ███████
+-- ████   ██ ██       ██   ██ ██    ██ ██    ██ ██   ██ ██     
+-- ██ ██  ██ ██   ███ ██████  ██    ██ ██    ██ ██████  ███████
+-- ██  ██ ██ ██    ██ ██   ██ ██    ██ ██    ██ ██           ██
+-- ██   ████  ██████  ██   ██  ██████   ██████  ██      ███████
+
+worldeditadditions_core.register_command("ngroups", {
+	params = "<node_name> [v[erbose]]",
+	description =
+	"Lists the groups that a given node is a part of. If v or verbose are tagged on the end, then group values are also displayed. See also //nodeapply, which pairs well with this command.",
+	privs = {},
+	parse = function(params_text)
+		local parts = wea_c.split_shell(params_text)
+		if #parts == 0 or parts[1] == "" then
+			return false, "Error: No node name specified."
+		end
+		
+		local node_name = worldedit.normalize_nodename(parts[1])
+		if not node_name then
+			return false, "Error: Unknown node "..parts[1].."."
+		end
+		
+		local verbose = false
+		if parts[2] == "v" or parts[2] == "verbose" then
+			verbose = true
+		end
+		
+		return true, node_name, verbose
+	end,
+	nodes_needed = function()
+		return 0
+	end,
+	func = function(_, node_name, verbose)
+		local node_def = minetest.registered_nodes[node_name]
+		if not node_def then return false, "Error: Failed to find definition for node "..node_name.."." end
+		
+		local msg = { node_name, "∈" }
+		for group_name, value in pairs(node_def.groups) do
+			local part = group_name
+			if verbose then
+				part = part.."="..tostring(value)
+			end
+			table.insert(msg, part)
+		end
+		
+		return true, table.concat(msg, " ")
+	end
+})

worldeditadditions_commands/init.lua

@@ -42,6 +42,9 @@ dofile(wea_cmd.modpath.."/commands/revolve.lua")
 -- Meta Commands
 dofile(wea_cmd.modpath .. "/commands/meta/init.lua")
 
+-- Node Informational Commands
+dofile(wea_cmd.modpath .. "/commands/nodes/init.lua")
+
 -- Selection Tools
 dofile(wea_cmd.modpath.."/commands/selectors/init.lua")
 

worldeditadditions_core/utils/NodeListMatcher.lua

@@ -116,7 +116,7 @@ function NodeListMatcher.match_group(matcher, node_id, group_name)
 	
 	-- 2: Nope, not in the cache. Time to query!
 	local node_name = minetest.get_name_from_content_id(node_id)
-	local group_value = minetest.get_item_group(node_name, "group:"..group_name)
+	local group_value = minetest.get_item_group(node_name, group_name)
 	if group_value == 0 then group_value = false
 	else group_value = true end