Generic interpreter in Haskell

interpreter.hs

module Data.Gerber.Interpreter where

import Data.Gerber.Types

data InterpreterState = InterpreterState
  { commandsParsed :: Integer }
  deriving (Show, Eq)

initState = InterpreterState
  { commandsParsed = 0 }

eval :: Command -> InterpreterState -> InterpreterState
eval command state =
  InterpreterState { commandsParsed = commandsParsed state + 1 }

evalBulk :: [Command] -> InterpreterState
evalBulk cmds = go cmds initState
  where
    go :: [Command] -> InterpreterState -> InterpreterState
    go []     imm = imm
    go (x)    imm = eval x imm
    go (x:xs) imm = go xs $ eval x imm