Randomized naming for Thangs

app/lib/world/rand.coffee

@@ -32,4 +32,14 @@ class Rand
   rand2: (min, max) =>
     min + @rand max - min
 
+  # return an array of randomly shuffled numbers from 0 to n, exclusive
+  randArray: (n) =>
+    array = ( i for i in [0..(n-1)] )
+
+    for i in [0..(n-1)]
+      r = @rand n
+      [ array[i], array[r] ] = [ array[r], array[i] ]
+
+    array
+
 module.exports = Rand

app/lib/world/thang.coffee

@@ -1,17 +1,31 @@
 ThangState = require './thang_state'
 {thangNames} = require './names'
 {ArgumentError} = require './errors'
+Rand = require './rand'
 
 module.exports = class Thang
   @className: "Thang"
+  @random = new Rand 0
+  @ordering: (spriteName) ->
+    Thang.orders ?= {}
+    names = thangNames[spriteName]
+    if names
+      len = names.length
+      array = Thang.orders[spriteName]
+      if !array?
+        array = @random.randArray len
+        Thang.orders[spriteName] = array
+    else
+      array = []
   @nextID: (spriteName) ->
     Thang.lastIDNums ?= {}
     names = thangNames[spriteName]
+    order = @ordering spriteName
     if names
       lastIDNum = Thang.lastIDNums[spriteName]
       idNum = (if lastIDNum? then lastIDNum + 1 else 0)
       Thang.lastIDNums[spriteName] = idNum
-      id = names[idNum % names.length]
+      id = names[order[idNum % names.length]]
       if idNum >= names.length
         id += Math.floor(idNum / names.length) + 1
     else
@@ -137,4 +151,4 @@ module.exports = class Thang
     for prop, val of o.finalState
       # TODO: take some (but not all) of deserialize logic from ThangState to handle other types
       t[prop] = val
-    t
+    t