diff --git a/custrom_functions_you_can_override.lua b/custrom_functions_you_can_override.lua
index 30bf21d..52b23e6 100644
--- a/custrom_functions_you_can_override.lua
+++ b/custrom_functions_you_can_override.lua
@@ -79,13 +79,15 @@ yl_speak_up.custom_server_functions.precondition_eval = function(player, descr,
 
 	elseif(descr == "(internal) player has priv:") then
 		-- the name of the priv is derived from the parameter
-		if(minetest.check_player_privs(player,
-				minetest.string_to_privs(tostring(precondition.p_var_cmp_value)))) then
-			-- TODO: change to true/false when new operator is available
-			return tostring(precondition.p_var_cmp_value)
-		else
-			return "false"
+		local ret = minetest.check_player_privs(player,
+				minetest.string_to_privs(tostring(precondition.p_var_cmp_value)))
+		-- evaluate the parameter directly
+		if(not(ret) or precondition.p_operator == "true_for_param"
+		            or precondition.p_operator == "false_for_param") then
+			return ret
 		end
+		-- return the parameter for == / != comparison
+		return tostring(precondition.p_var_cmp_value)
 
 	-- if this custom server function does not exist: return false
 	else
diff --git a/exec_eval_preconditions.lua b/exec_eval_preconditions.lua
index d6648d6..ee48383 100644
--- a/exec_eval_preconditions.lua
+++ b/exec_eval_preconditions.lua
@@ -101,6 +101,11 @@ yl_speak_up.eval_precondition = function(player, n_id, p, other_options_true_or_
 			-- evaluate it
 			var_val = yl_speak_up.custom_server_functions.precondition_eval(
 					player, p.p_variable, p)
+			if(p.p_operator == "true_for_param") then
+				return var_val
+			elseif(p.p_operator == "false_for_param") then
+				return not(var_val)
+			end
 		else
 			local pname = player:get_player_name()
 			local owner = yl_speak_up.npc_owner[ n_id ]
diff --git a/fs_edit_preconditions.lua b/fs_edit_preconditions.lua
index eb0d48a..bb207c8 100644
--- a/fs_edit_preconditions.lua
+++ b/fs_edit_preconditions.lua
@@ -1,6 +1,3 @@
--- TODO: check inscription of a sign?
--- TODO: check mesecons related things?
---
 -- This file contains what is necessary to add/edit a precondition.
 --
 -- Which diffrent types of preconditions are available?
@@ -140,12 +137,14 @@ local check_operator = {
 	"less than x seconds ago", -- 12
 	"has completed quest step", -- 13
 	"quest step *not* completed", -- 14
+	"is true for parameter:", -- 15
+	"is false for parameter:", -- 16
 }
 
 -- how to store these as p_value (the actual variable is stored in p_variable, and the value in p_cmp_value):
 local values_operator = {"", "==", "~=", ">=", ">", "<=", "<", "not", "is_set", "is_unset",
 	"more_than_x_seconds_ago","less_than_x_seconds_ago",
-	"quest_step_done", "quest_step_not_done"}
+	"quest_step_done", "quest_step_not_done", "true_for_param", "false_for_param"}
 
 
 
@@ -206,6 +205,12 @@ yl_speak_up.show_precondition = function(p, pname)
 		elseif(p.p_operator == "quest_step_not_done") then
 			return var_name.." shows: player has not yet completed quest step \""..
 				tostring(p.p_var_cmp_value).."\""
+		elseif(p.p_operator == "true_for_param") then
+			return var_name.." is true if called with parameter: \""..
+				tostring(p.p_var_cmp_value).."\""
+		elseif(p.p_operator == "false_for_param") then
+			return var_name.." is false if called with parameter: \""..
+				tostring(p.p_var_cmp_value).."\""
 		end
 		if(p.p_var_cmp_value == "") then
 			return var_name.." "..tostring(p.p_operator).." \"\""
@@ -327,7 +332,8 @@ yl_speak_up.get_fs_edit_preconditions = function(player, table_click_result)
 		-- show one precondition element
 		yl_speak_up.show_precondition,
 		"table_of_preconditions",
-		"The following expression shall be true:", "Operator:", "Value to compare with:",
+		"The following expression shall be true:", "Operator:",
+		"Value to compare with (in some cases parameter):",
 		"The following shall be true about the block:"
 		)
 end