mcl_inventory API documentation + fix

mods/HUD/mcl_inventory/API.md

@@ -0,0 +1,35 @@
+# `mcl_inventory`
+
+## `mcl_inventory.register_survival_inventory_tab(def)`
+
+```lua
+mcl_inventory.register_survival_inventory_tab({
+	-- Page identifier
+	-- Used to uniquely identify the tab
+	id = "test",
+
+	-- The tab description, can be translated
+	description = "Test",
+
+	-- The name of the item that will be used as icon
+	item_icon = "mcl_core:stone",
+
+	-- If true, the main inventory will be shown at the bottom of the tab
+	-- Listrings need to be added by hand
+	show_inventory = true,
+
+	-- This function must return the tab's formspec for the player
+	build = function(player)
+		return "label[1,1;Hello hello]button[2,2;2,2;Hello;hey]"
+	end,
+
+	-- This function will be called in the on_player_receive_fields callback if the tab is currently open
+	handle = function(player, fields)
+		print(dump(fields))
+	end,
+
+	-- This function will be called to know if a player can see the tab
+	-- Returns true by default
+	access = function(player)
+	end,
+```

mods/HUD/mcl_inventory/survival.lua

@@ -21,6 +21,10 @@ function mcl_inventory.register_survival_inventory_tab(def)
 	assert(def.build)
 	assert(def.handle)
 
+	for _, d in ipairs(mcl_inventory.registered_survival_inventory_tabs) do
+		assert(d.id ~= def.id, "Another tab exists with the same name!")
+	end
+
 	if not def.access then
 		function def.access(player)
 			return true
@@ -62,6 +66,7 @@ local function build_page(player, content, inventory, tabname)
 					",-1.34;1.5,1.44;" .. (tabname == d.id and "crafting_creative_active.png" or "crafting_creative_inactive.png") ..
 					"]",
 				"item_image_button[" .. (0.44 + (i - 1) * 1.6) .. ",-1.1;1,1;" .. d.item_icon .. ";" .. btn_name .. ";]",
+				"tooltip[" .. btn_name .. ";" .. F(d.description) .. "]"
 			})
 		end
 	end