+
+
+function table.insert_all(t, other)
+ for i=1, #other do
+ t[#t + 1] = other[i]
+ end
+ return t
+end
+
+
+function table.key_value_swap(t)
+ local ti = {}
+ for k,v in pairs(t) do
+ ti[v] = k
+ end
+ return ti
+end
+
+
+function table.shuffle(t, from, to, random)
+ from = from or 1
+ to = to or #t
+ random = random or math.random
+ local n = to - from + 1
+ while n > 1 do
+ local r = from + n-1
+ local l = from + random(0, n-1)
+ t[l], t[r] = t[r], t[l]
+ n = n-1
+ end
+end
+
+