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-rw-r--r--lec08/Party.hs20
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diff --git a/lec08/Party.hs b/lec08/Party.hs
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+module Party where
+
+import Employee
+
+-- Exercise 1
+
+glCons :: Employee -> GuestList -> GuestList
+glCons e { empFun = ef } (GL es cf) = GL (e:es) (cf + ef)
+
+-- mappend (a.k.a. (<>)) has been moved to Semigroup
+instance Semigroup GuestList where
+ (<>) (GL es1 f1) (GL es2 f2) = GL (es1 ++ es2) (f1 + f2)
+
+instance Monoid GuestList where
+ mempty = GL [] 0
+
+moreFun :: GuestList -> GuestList -> GuestList
+moreFun gl1@(GL _ f1) gl2@(GL _ f2)
+ | f1 >= f2 = gl1
+ | otherwise = gl2