--
module SimpleGraphics where
import SOEGraphics
---------------------------------------------------------------
----- first the code from the lecture that talks about actions
data Bintree a = Lf a
| (Bintree a) :/\: (Bintree a)
leftmost :: a -> Bintree a -> Bintree a
leftmost new (Lf x) = Lf new
leftmost new (x :/\: y) = (leftmost new x) :/\: y
replace :: Eq a => a -> a -> Bintree a -> Bintree a
replace new old (Lf x) =
if x==old then Lf new else Lf x
replace new old (x :/\: y) =
(replace new old x) :/\: (replace new old y)
replace' :: Eq a => a -> a -> Bintree a -> Bintree a
replace' new old w =
let replace2 (Lf x) =
if x==old then (Lf new,True) else (Lf x,False)
replace2 (x :/\: y) =
(case (replace2 x,replace2 y) of
((a,False),(b,False)) -> (x :/\: y, False)
((a,True),(b,False)) -> (a :/\: y,True)
((a,False),(b,True)) -> (x :/\: b,True)
((a,True),(b,True)) -> (a :/\: b,True))
in fst(replace2 w)
ex2 :: IO ()
ex2 =
do { c1 <- getChar ; c2 <- getChar -- the newline ; putChar c1 ; putChar c2 } getLine' :: IO [Char] getLine' = do { c <- getChar -- get a char ; if c == '\n' -- if its newline then return "" -- no-op action which -- returns empty string -- recursively else do { l <- getLine' -- get a line ; return (c:l) -- no-op action } -- to cons c to l } -- the word count example wc (cc,w,lc) [] = (cc,w,lc) wc (cc,w,lc) (' ' : xs) = wc (cc+1,w+1,lc) xs wc (cc,w,lc) ('\t' : xs) = wc (cc+1,w+1,lc) xs wc (cc,w,lc) ('\n' : xs) = wc (cc+1,w+1,lc+1) xs wc (cc,w,lc) (x : xs) = wc (cc+1,w,lc) xs ex7 = do { name <- getLine ; z <- readFile name ; let (cc,w,lc) = wc (0,0,0) z ; putStr ("The file: "++ name ++ " has \n "++(show cc)++ " characters\n "++(show w)++ " words\n "++(show lc)++ " lines\n") } ----------------------------------------------------------------- ----- Now the simple graphics code main = putStr "hello world" main0 = runGraphics( do { w <- openWindow "First window" (300,300) ; drawInWindow w (text (100,200) "hello world") ; k <- getKey w ; closeWindow w } ) spaceClose :: Window -> IO ()
spaceClose w =
do { k <- getKey w ; if k == ' ' then closeWindow w else spaceClose w } main1 = runGraphics( do { w <- openWindow "Second Program" (300,300) ; drawInWindow w (text (100,200) "hello Again") ; spaceClose w } ) --