diff options
| author | Camil Staps | 2016-02-02 19:24:50 +0100 |
|---|---|---|
| committer | Camil Staps | 2016-02-02 19:24:50 +0100 |
| commit | a7d7542dc646a5fd124ef71e71ce260889f1701b (patch) | |
| tree | 04ed89503bbb3cc9933273a1326a53ca724c3492 /1415/fp2/week2/mart/StdIOMonad.icl | |
| parent | week6 camil: working positioning of lines by putting empties at left and righ... (diff) | |
Diffstat (limited to '1415/fp2/week2/mart/StdIOMonad.icl')
| -rw-r--r-- | 1415/fp2/week2/mart/StdIOMonad.icl | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/1415/fp2/week2/mart/StdIOMonad.icl b/1415/fp2/week2/mart/StdIOMonad.icl new file mode 100644 index 0000000..ffa2857 --- /dev/null +++ b/1415/fp2/week2/mart/StdIOMonad.icl @@ -0,0 +1,138 @@ +implementation module StdIOMonad
+
+import StdBool
+import StdEnum
+import StdFile
+import StdList
+import StdMaybe
+import StdMisc
+import StdMonad
+import StdOverloaded
+import StdString
+import StdTuple
+
+:: IO a = IO (*W -> *(a, *W))
+:: *W :== *(*World, *[*(Filehandle, *File)])
+:: Filemode = Lees | Schrijf
+:: Filenaam :== String
+:: Filehandle :== String
+
+// Conversion from our filemodes to StdFile filemodes
+instance toInt Filemode where
+ toInt Lees = FReadText
+ toInt Schrijf = FWriteText
+
+// Apply the monadic program on the world
+doIO:: (IO a) *World -> *(a, *W)
+doIO (IO f) w = f (w, [])
+
+// Lift the value out of the monadic domain
+unIO:: (IO a) -> *W -> *(a, *W)
+unIO (IO f) = f
+
+instance return IO where
+ return x = IO (\w -> (x, w))
+instance >>= IO where
+ (>>=) (IO f) g = IO (\w = let (a, w1) = f w in unIO (g a) w1)
+
+// Read one line from the console
+read:: IO String
+read = IO read`
+ where
+ read`:: *W -> *(String, *W)
+ read` (world, s)
+ # (io, world) = stdio world
+ # (line, io) = freadline io
+ # (_, world) = fclose io world
+ = (line, (world, s))
+
+// Write a line from the console
+write :: String -> IO Void
+write s = IO (write` s)
+ where
+ write`:: String *W -> *(Void, *W)
+ write` line (world, s)
+ # (io, world) = stdio world
+ # io = io <<< line
+ # (_, world) = fclose io world
+ = (Void, (world, s))
+
+// Open a file
+open:: Filenaam Filemode -> IO (Maybe Filehandle)
+open s m = IO (open` s m)
+ where
+ open`:: String Filemode *W -> *(Maybe Filehandle, *W)
+ open` fp m (world, fs)
+ | any (\l = fp == fst l) fs = (Nothing, (world, fs))
+ # (ok, file, world) = fopen fp (toInt m) world
+ = (Just fp, (world, [(fp, file):fs]))
+
+// Close a file. If the file can't be closed by the system the program will
+// abort
+close:: Filehandle -> IO Bool
+close fh = IO (close` fh)
+ where
+ close`:: Filehandle *W -> *(Bool, *W)
+ close` fp (world, fs)
+ # (currentfiletuple, fs) = getFH fp fs
+ | isNothing currentfiletuple = (False, (world, fs))
+ # (currentfh, currentfile) = fromJust currentfiletuple
+ # (ok, world) = fclose currentfile world
+ | not ok = abort "File can't be closed"
+ | otherwise = (True, (world, fs))
+
+
+// Determine if the file is at the end. This will abort when the file is not
+// open or error if the file is not opened for reading.
+eof :: Filehandle -> IO Bool
+eof fh = IO (eof` fh)
+ where
+ eof`:: Filehandle *W -> *(Bool, *W)
+ eof` fp (world, fs)
+ # (currentfiletuple, fs) = getFH fp fs
+ | isNothing currentfiletuple = abort "Can't do eof on non-existing file"
+ # (currentfh, currentfile) = fromJust currentfiletuple
+ # (ok, file) = fend currentfile
+ = (ok, (world, [(currentfh, file):fs]))
+
+// Read one line from a file (including newline). This will abort when the file
+// is not open or error if the file is not opened for reading.
+readline :: Filehandle -> IO (Maybe String)
+readline fh = IO (readline` fh)
+ where
+ readline` :: Filehandle *W -> *(Maybe String, *W)
+ readline` fh (world, fs)
+ # (currentfiletuple, fs) = getFH fh fs
+ | isNothing currentfiletuple = abort "File not open"
+ # (currentfh, currentfile) = fromJust currentfiletuple
+ # (s, currentfile) = freadline currentfile
+ = (Just s, (world, [(currentfh, currentfile):fs]))
+
+// Write one line from a file (will not append newline). This will abort when
+// the file is not open or error if the file is not opened for writing.
+writeline :: String Filehandle -> IO Bool
+writeline s fh = IO (writeline` s fh)
+ where
+ writeline` :: String Filehandle *W -> *(Bool, *W)
+ writeline` s fh (world, fs)
+ # (currentfiletuple, fs) = getFH fh fs
+ | isNothing currentfiletuple = abort "File not open"
+ # (currentfh, currentfile) = fromJust currentfiletuple
+ # currentfile = fwrites s currentfile
+ = (True, (world, [(currentfh, currentfile):fs]))
+
+// Gets the file associated with the filehandle given, this is done in a very
+// ugly way to retain uniqueness...
+getFH:: Filehandle *[*(Filehandle, *File)] ->
+ (Maybe *(Filehandle, *File), *[*(Filehandle, *File)])
+getFH fh fs
+# (fhs, fis) = unzip fs
+# fhsC = zip2 [0..length fhs] fhs
+# index = [(i, h) \\ (i, h) <- fhsC | h == fh]
+| length index == 0 = (Nothing, zip2 fhs fis)
+# index = fst (hd index)
+# (fis1, fis2) = splitAt index fis
+# (fhs1, fhs2) = splitAt index fhs
+# (thefile, fis2) = splitAt 1 fis2
+# (thehandle, fhs2) = splitAt 1 fhs2
+= (Just (hd thehandle, hd thefile), zip2 (fhs1 ++ fhs2) (fis1 ++ fis2))
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