[Haskell-cafe] Constructors on left and right hand sides of equation

[PATRICK BROWNE]

Dear list
In Eq 1 is  (NewGlass i) on the LHS distinct from (NewGlass i) on the RHS?
In Eq2  are the occurrences  of the data constructor Fill on the LHS and
RHS distinct?

Thanks
Pat


data Glass = NewGlass Int | Fill Glass Int deriving Show
drink :: Glass -> Int -> Glass
drink (NewGlass i) j = (NewGlass i)   -- Eq 1
drink (Fill m i) j
               | full (Fill m i)  = Fill (NewGlass (size m))  ((size m) -
j)  -- Eq 2
               | (i >= j) = Fill m  (i-j)
               | otherwise = drink m (j-1)

size :: Glass -> Int
size (NewGlass i) = i
size (Fill m i) = size m

level :: Glass -> Int
level (NewGlass i) = 0
level (Fill m i)
                | (level m) + i > (size m) = size m
                | otherwise = (level m) + i

empty :: Glass -> Bool
empty m = (level m) == 0


full :: Glass -> Bool
full m = (level m) == (size m)
{-
drink (Fill (NewGlass 4) 5) 5
drink (Fill (NewGlass 4) 3) 3
-}

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