fp2/week1/mart/SimpleFileIO.icl

   1 implementation module SimpleFileIO
   2
   3 import StdEnv, StdFile, StdOverloaded, StdMaybe
   4
   5 // 1.
   6 readFile        :: String                 *env -> (Maybe String,  *env) | FileSystem env
   7 readFile s env
   8 # (ss, env) = readLines s env
   9 | ss == Nothing = (Nothing, env)
  10 | otherwise = (Just (foldl (+++) "" (fromJust ss)), env)
  11
  12 writeFile       :: String String          *env -> (Bool,          *env) | FileSystem env
  13 writeFile fn s env
  14 # (ok, outfile, env) = fopen fn FWriteText env
  15 | not ok = (False, env)
  16 # outfile = fwrites s outfile
  17 # (ok, env) = fclose outfile env
  18 | otherwise = (ok, env)
  19
  20 // 2.
  21 readLines       :: String                 *env -> (Maybe [String],*env) | FileSystem env
  22 readLines s env
  23 # (ok, infile, env) = sfopen s FReadText env
  24 | not ok = (Nothing, env)
  25 | otherwise = (Just (fst (readLines` infile)), env)
  26 where
  27         readLines` :: File -> ([String], File)
  28         readLines` file
  29         | sfend file = ([], file)
  30         # (line, file) = sfreadline file
  31         # (ss, file) = readLines` file
  32         | otherwise = ([line : ss], file)
  33
  34 writeLines      :: String [String]        *env -> (Bool,          *env) | FileSystem env
  35 writeLines fn ss env = writeFile fn (foldl (+++) "" [s +++ "\n" \\ s <- ss]) env
  36
  37 // 3.
  38 //mapFile               :: String String (a -> b) *env -> (Bool,          *env) | FileSystem env & ... a & ... b
  39