haskell/Printer.hs

   1 module Printer
   2 ( _pr_str, _pr_list )
   3 where
   4
   5 import qualified Data.Map as Map
   6 import Data.IORef (readIORef)
   7 import System.IO.Unsafe (unsafePerformIO)
   8
   9 import Types
  10
  11 --concat (map (++ delim) list)
  12 --join [] delim = []
  13 --join (x:xs) delim = x ++ delim  ++ join xs delim
  14
  15
  16 _pr_list :: Bool -> String -> [MalVal] -> String
  17 _pr_list pr sep [] = []
  18 _pr_list pr sep (x:[]) = (_pr_str pr x)
  19 _pr_list pr sep (x:xs) = (_pr_str pr x) ++ sep ++ (_pr_list pr sep xs)
  20
  21 _flatTuples ((a,b):xs) = MalString a : b : _flatTuples xs
  22 _flatTuples _          = []
  23
  24 unescape chr = case chr of
  25     '\n' -> "\\n"
  26     '\\' -> "\\\\"
  27     '"'  -> "\\\""
  28     c    -> [c]
  29
  30 _pr_str :: Bool -> MalVal -> String
  31 _pr_str _     (MalString ('\x029e':str)) = ":" ++ str
  32 _pr_str True  (MalString str) = "\"" ++ concatMap unescape str ++ "\""
  33 _pr_str False (MalString str) = str
  34 _pr_str _     (MalSymbol name) = name
  35 _pr_str _     (MalNumber num) = show num
  36 _pr_str _     (MalTrue) = "true"
  37 _pr_str _     (MalFalse) = "false"
  38 _pr_str _     (Nil) = "nil"
  39 _pr_str pr    (MalList items _) = "(" ++ (_pr_list pr " " items) ++ ")"
  40 _pr_str pr    (MalVector items _) = "[" ++ (_pr_list pr " " items) ++ "]"
  41 _pr_str pr    (MalHashMap m _) = "{" ++ (_pr_list pr " " (_flatTuples $ Map.assocs m)) ++ "}"
  42 _pr_str pr    (MalAtom r _) = "(atom " ++ (_pr_str pr (unsafePerformIO (readIORef r))) ++ ")"
  43 _pr_str _     (Func f _) = "#<function>"
  44 _pr_str _     (MalFunc {ast=ast, env=fn_env, params=params}) = "(fn* " ++ (show params) ++ " " ++ (show ast) ++ ")"
  45
  46 instance Show MalVal where show = _pr_str True
  47