decouple icon from text, see #19

luigi/cleaner.lua

@@ -0,0 +1,32 @@
+local Cleaner = {}
+
+local marked = {}
+local watched = setmetatable({}, { __mode = 'k' })
+
+function Cleaner.mark (t, key)
+    local length = #marked
+    local keys = watched[t]
+    if not keys then
+        keys = {}
+        watched[t] = keys
+    elseif keys[key] then
+        return
+    end
+    keys[key] = true
+    local i = length + 1
+    marked[i] = t
+    marked[i + 1] = key
+end
+
+function Cleaner.clean ()
+    for i = #marked - 1, 1, -2 do
+        local t = marked[i]
+        local key = marked[i + 1]
+        t[key] = nil
+        marked[i] = nil
+        marked[i + 1] = nil
+        watched[t][key] = nil
+    end
+end
+
+return Cleaner