From e2e345520ca8ffcaece19d27007e87dcfa02d864 Mon Sep 17 00:00:00 2001
From: Ben Sima <ben@bsima.me>
Date: Sat, 30 Jun 2018 10:14:47 -0700
Subject: Split `run` into a helper function and use a new random gen every
 time

---
 simspace/Main.hs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

(limited to 'simspace')

diff --git a/simspace/Main.hs b/simspace/Main.hs
index 07d2705..229bba4 100644
--- a/simspace/Main.hs
+++ b/simspace/Main.hs
@@ -2,7 +2,7 @@ module Main where
 
 import System.Environment
 import Control.Monad
-import System.Random (getStdGen, randomRs)
+import System.Random (newStdGen, randomRs)
 import Data.List.Split
 
 main :: IO ()
@@ -12,10 +12,17 @@ main = do
         [] -> putStrLn "Needs one argument"
         (n:_) -> run (read n :: Int)
 
+-- | Run the cellular automata with a random seed.
 run :: Int -> IO ()
 run n = do
-    g <- getStdGen
+    g <- newStdGen
     let init = take n $ randomRs (0,1) g
+    run' init
+
+-- | Version of 'run' that allows for entering your own initial seed.
+run' :: [Int] -> IO ()
+run' init = do
+    let n = length init
     let zeros = take n $ repeat 0
     let result = takeWhile' (/= zeros) $ chunksOf n $ compute n init
     forM_ result $ \r -> putStrLn $ show r
-- 
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