Python identifier generator

Names.hs

module Names (renderName) where

import Data.List (genericIndex)

-- | Map a non-negative integer to a valid Python identifier.
renderName :: Integer -> String
renderName
    = ('_':)  -- Prevent conflict with Python keywords
    . map (genericIndex chars)
    . digitify (fromIntegral $ length chars)

chars = '_' : ['a'..'z']

digitify :: Integer -> Integer -> [Integer]
digitify limit = reverse . step . (+1)
  where
    step x
      | x <= 0 = []
      | otherwise = i : step x'
      where
        (x', i) = (x-1) `divMod` limit

main = mapM_ (putStrLn . renderName) [0..755]