Add ability to speak, and fix runtime actions so they will return new results if called with different parameters

abilities.lua

@@ -240,6 +240,9 @@ robot.add_ability({
 
 		return core.get_node(dirPos.frontpos).name
 	end,
+	runtime_unique = function (part, dir)
+		return part..dir
+	end,
 	runtime = true
 })
 
@@ -278,6 +281,33 @@ robot.add_ability({
 	runtime = true
 })
 
+-- [[ Speak ]]
+robot.add_ability({
+	ability = "speak",
+	item = function ()
+		if core.get_modpath('homedecor') then
+			return 'homedecor:speaker_driver'
+		end
+		return "default:pine_sapling"
+	end,
+	act_on = 'last',
+	depends_on = 'any',
+	description = S("Send chat messages to the owner"),
+	command_example = "robot.speak('Hello!')",
+	done_by = { head = true },
+	action = function (nodeinfo, part, message)
+		local hasability = api.any_has_ability(nodeinfo, 'speak')
+		if not hasability then return end
+
+		local meta = nodeinfo.meta()
+		local owner = meta:get_string('player_name')
+		core.chat_send_player(owner, "[robot] "..message)
+
+		return nil
+	end,
+	runtime = true
+})
+
 local function is_default_method(obj, key)
 	local method = obj[key]
 	return (key == 'on_place' and method == core.item_place)

api/execute.lua

@@ -219,16 +219,14 @@ local function save_memory(nodeinfo, mem)
 	end
 end
 
-local function runtime_ability(nodeinfo, action, part)
-	local ran = false
-	local result
+local function runtime_ability(nodeinfo, ability, part)
+	local cached_results = {}
 	return function (...)
-		if ran then
-			return result
+		local unique = ability.runtime_unique and ability.runtime_unique(part or 'main', ...) or part or 'main'
+		if cached_results[unique] == nil then
+			cached_results[unique] = ability.action(nodeinfo, part or 'main', ...)
 		end
-		ran = true
-		result = action(nodeinfo, part, ...)
-		return result
+		return cached_results[unique]
 	end
 end
 
@@ -277,10 +275,10 @@ local function run_inner(nodeinfo)
 					end
 				end
 			elseif ability.runtime then
-				commands[ability.ability] = runtime_ability(nodeinfo, ability.action)
+				commands[ability.ability] = runtime_ability(nodeinfo, ability)
 				for _,part in ipairs(parts) do
 					if commands[part] then
-						commands[part][ability.ability] = runtime_ability(nodeinfo, ability.action, part)
+						commands[part][ability.ability] = runtime_ability(nodeinfo, ability, part)
 					end
 				end
 			else