Hi, I am new to Haskell. I programmed in imperative languages for many years and I have been using Mathematica for the last 15 years which mixes functional and imperative programming. I started learning Haskell about 2 months ago mostly by reading the first 13.5 chapters of Real World Haskell and doing about 50 of the Euler Problems. "The Evolution of a Haskell Programmer", the Haskell Wiki, and this listserv have also been helpful. I figured I should try a larger program in Haskell, so I am converting one of my Mathematica programs, a simulator for the card game Dominion, over to Haskell. Most of that is going well except for one patch of imperative code. My Haskell version of this code is ugly. I was hoping someone could recommend a better way to do it. I will paste a simplified version of the code below. If necessary, I can provide all the other code used for this simplified example (about 30 more lines of Haskell code, or an equivalent program in C++ (130 lines of code). Cheers, Hein -----------------Ugly Haskell Code------------------------- data LoopState = LSt GameState Strat Int Int Int [Int] Int Int Bool proc :: GameState -> Strat -> (Int, Int, GameState) proc gs' strat = let iA = 1 iTh = 0 i = 0 aA = replicate 20 0 iB = 1 iC = 0 bDone = False gs = apps ("<<<"++show(gs')++">>>") gs' lst = LSt gs strat iA iTh i aA iB iC bDone lst2 = until isDone procloop lst isDone (LSt gs strat iA iTh i aA iB iC bDone) = bDone output (LSt gs strat iA iTh i aA iB iC bDone) = (iB, iC, appd aA gs) in output lst2 procloop :: LoopState -> LoopState procloop (LSt gs' strat iA iTh i aA iB iC bDone) = do let iCd = stratchoose strat gs' iA iTh iB aA let gs = apps ("iB "++show iB++ "\n" ) gs' if iA<=0 || i>=20 || actcd gs <=0 || iCd == -1 then LSt gs strat iA iTh (i+1) aA iB iC True else if iCd == 1 then LSt gs strat iA (iTh+1) (i+1) aA iB iC False else let gs2 = delh iCd gs aA2 = append aA iCd (iA3, iC3, iB3, gs3, aA3) = doAct iA iC iB gs2 aA2 strat iCd (iA4, iC4, iB4, gs4, aA4) = doAct iA3 iC3 iB3 gs3 aA3 strat iCd in if iTh>0 then LSt gs4 strat iA4 (iTh-1) (i+1) aA4 iB4 iC4 False else LSt gs3 strat iA3 (iTh-1) (i+1) aA3 iB3 iC3 False ---------------end of Haskell code-------------------------------