Implement unique dialog names

API.md

@@ -7,7 +7,7 @@ to check for the mod's existence first (`minetest.get_modpath`
 returns non-`nil` value).
 
 ## Functions
-### `select_item.show_dialog(playername, filter)`
+### `select_item.show_dialog(playername, dialogname, filter)`
 Shows an item selection dialog to a player. The player can choose
 one item (which triggers a callback) or abort selection
 (in which case nothing happens).
@@ -20,9 +20,12 @@ to filter out unwanted items.
 
 #### Parameters
 * `playername`: Name of player to show dialog to
+* `dialogname`: Unique identifier of the dialog
 * `filter`: Optional filter function to narrow down the visible
    items (see below)
 
+Recommended form of `dialogname` is “`<modname>:<name>`”.
+
 #### Filter function
 The filter function has the function signature `filter(itemstring)`.
 This function will be called for each item with the itemstring
@@ -42,8 +45,9 @@ Whenever a player selects an item or cancels the selection,
 `callback` is called.
 
 #### `callback` function
-This has the function signature `callback(playername, itemstring)`.
+This has the function signature `callback(identifier, playername, itemstring)`.
 
+* `identifier` is the identifier of the item formspec
 * `playername` is the name of the player who selected the item,
 * `itemstring` is the itemstring of the chosen item or `nil` if aborted
 

init.lua

@@ -68,8 +68,9 @@ local xsize_norm = 12
 local ysize_norm = 9
 
 -- Opens the item selection dialog for player with the given filter function at page.
+-- The dialog has unique identifier dialogname.
 -- Returns: Number of items it displays.
-local show_dialog_page = function(playername, filter, page)
+local show_dialog_page = function(playername, dialogname, filter, page)
 	local items
 	if player_filters[playername] == nil then
 		player_filters[playername] = filter
@@ -131,12 +132,12 @@ local show_dialog_page = function(playername, filter, page)
 		form = form .. "label[2,"..ynav..";"..minetest.formspec_escape(string.format("Page %d/%d", page, total_pages)).."]"
 	end
 	form = form .. "button_exit["..(xsize-2)..","..ynav..";2,1;cancel;Cancel]"
-	minetest.show_formspec(playername, "select_item:page"..page, form)
+	minetest.show_formspec(playername, "select_item:page"..page.."_"..dialogname, form)
 	return #items
 end
 
-select_item.show_dialog = function(playername, filter)
-	show_dialog_page(playername, filter, 1)
+select_item.show_dialog = function(playername, dialogname, filter)
+	show_dialog_page(playername, dialogname, filter, 1)
 end
 
 local callbacks = {}
@@ -147,6 +148,12 @@ end
 minetest.register_on_player_receive_fields(function(player, formname, fields)
 	local playername = player:get_player_name()
 	if string.sub(formname, 1, 16) == "select_item:page" then
+		-- Parse formname
+		local rest = string.sub(formname, 17, string.len(formname))
+		local split = string.split(rest, "_", true, 2)
+		local page = tonumber(split[1])
+		local dialogname = split[2]
+
 		local item
 		for field,_ in pairs(fields) do
 			if string.sub(field, 1, 5) == "item_" then
@@ -157,7 +164,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		if item or fields.quit then
 			local close = true
 			for i=1,#callbacks do
-				local ret = callbacks[i](playername, item)
+				local ret = callbacks[i](playername, dialogname, item)
 				if ret == false then
 					close = false
 				end
@@ -170,14 +177,13 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		if fields.quit or fields.cancel then
 			reset_player_info(playername)
 		end
-		local page = tonumber(string.sub(formname, 17, string.len(formname)))
 		if page ~= nil then
 			if fields.previous and page > 1 then
-				show_dialog_page(player:get_player_name(), player_filters[playername], page - 1)
+				show_dialog_page(player:get_player_name(), dialogname, player_filters[playername], page - 1)
 			elseif fields.next then
 				local maxpage = player_maxpage[playername]
 				if maxpage and (page + 1 <= maxpage) then
-					show_dialog_page(playername, player_filters[playername], page + 1)
+					show_dialog_page(playername, dialogname, player_filters[playername], page + 1)
 				end
 				if not maxpage then
 					minetest.log("warning", "[select_item] Player "..playername.." managed to navigate select_item menu without maxpage set!")