diff --git a/test.lua b/test.lua
index fe10b63..7b303b8 100644
--- a/test.lua
+++ b/test.lua
@@ -6,3 +6,71 @@ local systemB = tiny.system()
 world:addSystem(systemA)
 world:addSystem(systemB)
 world:setSystemIndex(systemA, 1)
+
+
+--- test requireXXX/rejectXXX functions
+
+local filt1 = tiny.requireAll("prop1", "prop2")
+
+assert(filt1(nil, { }) == false)
+assert(filt1(nil, { prop1 = 1 }) == false)
+assert(filt1(nil, { prop1 = 1, prop3 = 2}) == false)
+assert(filt1(nil, { prop1 = 1, prop2 = 2 }) == true)
+assert(filt1(nil, { prop2 = 1 }) == false)
+assert(filt1(nil, { prop2 = 1, prop1 = 1, prop3 = 2 }) == true)
+
+
+local filt2 = tiny.requireAny("prop1", "prop2")
+
+assert(filt2(nil, { }) == false)
+assert(filt2(nil, { prop1 = 1 }) == true)
+assert(filt2(nil, { prop1 = 1, prop3 = 2}) == true)
+assert(filt2(nil, { prop1 = 1, prop2 = 2 }) == true)
+assert(filt2(nil, { prop2 = 1 }) == true)
+assert(filt2(nil, { prop2 = 1, prop1 = 1, prop3 = 2 }) == true)
+assert(filt2(nil, { prop4 = 1, prop5 = 1, prop6 = 2 }) == false)
+
+
+local filt3 = tiny.rejectAll("prop1", "prop2")
+
+assert(filt3(nil, { }) == true)
+assert(filt3(nil, { prop1 = 1 }) == true)
+assert(filt3(nil, { prop1 = 1, prop3 = 2}) == true)
+assert(filt3(nil, { prop1 = 1, prop2 = 2 }) == false)
+assert(filt3(nil, { prop2 = 1 }) == true)
+assert(filt3(nil, { prop2 = 1, prop1 = 1, prop3 = 2 }) == false)
+
+
+local filt4 = tiny.rejectAny("prop1", "prop2")
+
+assert(filt4(nil, { }) == true)
+assert(filt4(nil, { prop1 = 1 }) == false)
+assert(filt4(nil, { prop1 = 1, prop3 = 2}) == false)
+assert(filt4(nil, { prop1 = 1, prop2 = 2 }) == false)
+assert(filt4(nil, { prop2 = 1 }) == false)
+assert(filt4(nil, { prop2 = 1, prop1 = 1, prop3 = 2 }) == false)
+assert(filt4(nil, { prop4 = 1, prop5 = 1, prop6 = 2 }) == true)
+
+
+
+local filt5 = tiny.requireAll("prop3", filt2)
+
+assert(filt5(nil, {}) == false)
+assert(filt5(nil, {prop1 = 1}) == false)
+assert(filt5(nil, {prop1 = 1, prop2 = 1, prop3 = 1}) == true)
+assert(filt5(nil, {prop1 = 1, prop2 = 1, prop3 = 1, prop4 = 1}) == true)
+assert(filt5(nil, {prop1 = 1, prop2 = 1, prop4 = 1}) == false)
+
+local filt6 = tiny.requireAny("prop3", filt2)
+
+assert(filt6(nil, {}) == false)
+assert(filt6(nil, {prop1 = 1}) == true)
+assert(filt6(nil, {prop1 = 1, prop2 = 1, prop3 = 1}) == true)
+assert(filt6(nil, {prop1 = 1, prop2 = 1, prop3 = 1, prop4 = 1}) == true)
+assert(filt6(nil, {prop1 = 1, prop2 = 1, prop4 = 1}) == true)
+assert(filt6(nil, {prop5 = 1, prop4 = 1}) == false)
+
+
+
+
+
diff --git a/tiny.lua b/tiny.lua
index 4dca2cd..f8e85aa 100644
--- a/tiny.lua
+++ b/tiny.lua
@@ -91,41 +91,50 @@ local filterJoin
 -- A helper function to filters from string
 local filterBuildString
 
+
+local function filterJoinRaw(invert, joining_op, ...)
+   local _args = {...}
+
+   return function(system, e)
+      local acc
+      local args = _args
+      if joining_op == 'or' then
+	 acc = false
+	 for i = 1, #args do
+	    local v = args[i]
+	    if type(v) == "string" then
+	       acc = acc or (e[v] ~= nil)
+	    elseif type(v) == "function" then
+	       acc = acc or v(system, e)
+	    else
+	       error 'Filter token must be a string or a filter function.'
+	    end
+	 end
+      else
+	 acc = true
+	 for i = 1, #args do
+	    local v = args[i]
+	    if type(v) == "string" then
+	       acc = acc and (e[v] ~= nil)
+	    elseif type(v) == "function" then
+	       acc = acc and v(system, e)
+	    else
+	       error 'Filter token must be a string or a filter function.'
+	    end
+	 end
+      end
+
+      -- computes a simple xor
+      if invert then
+	 return not acc
+      else
+	 return acc
+      end
+   end
+end
+
 do
 
-    local loadstring = loadstring or load
-    local function getchr(c)
-        return "\\" .. c:byte()
-    end
-    local function make_safe(text)
-        return ("%q"):format(text):gsub('\n', 'n'):gsub("[\128-\255]", getchr)
-    end
-
-    local function filterJoinRaw(prefix, seperator, ...)
-        local accum = {}
-        local build = {}
-        for i = 1, select('#', ...) do
-            local item = select(i, ...)
-            if type(item) == 'string' then
-                accum[#accum + 1] = ("(e[%s] ~= nil)"):format(make_safe(item))
-            elseif type(item) == 'function' then
-                build[#build + 1] = ('local subfilter_%d_ = select(%d, ...)')
-                    :format(i, i)
-                accum[#accum + 1] = ('(subfilter_%d_(system, e))'):format(i)
-            else
-                error 'Filter token must be a string or a filter function.'
-            end
-        end
-        local source = ('%s\nreturn function(system, e) return %s(%s) end')
-            :format(
-                table.concat(build, '\n'),
-                prefix,
-                table.concat(accum, seperator))
-        local loader, err = loadstring(source)
-        if err then error(err) end
-        return loader(...)
-    end
-
     function filterJoin(...)
         local state, value = pcall(filterJoinRaw, ...)
         if state then return value else return nil, value end
@@ -169,25 +178,25 @@ end
 --- Makes a Filter that selects Entities with all specified Components and
 -- Filters.
 function tiny.requireAll(...)
-    return filterJoin('', ' and ', ...)
+    return filterJoin(false, 'and', ...)
 end
 
 --- Makes a Filter that selects Entities with at least one of the specified
 -- Components and Filters.
 function tiny.requireAny(...)
-    return filterJoin('', ' or ', ...)
+    return filterJoin(false, 'or', ...)
 end
 
 --- Makes a Filter that rejects Entities with all specified Components and
 -- Filters, and selects all other Entities.
 function tiny.rejectAll(...)
-    return filterJoin('not', ' and ', ...)
+    return filterJoin(true, 'and', ...)
 end
 
 --- Makes a Filter that rejects Entities with at least one of the specified
 -- Components and Filters, and selects all other Entities.
 function tiny.rejectAny(...)
-    return filterJoin('not', ' or ', ...)
+    return filterJoin(true, 'or', ...)
 end
 
 --- Makes a Filter from a string. Syntax of `pattern` is as follows.