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47 lines
1.3 KiB
47 lines
1.3 KiB
7 years ago
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# Chapter Excercises
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## Multiple choice
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1. (c)
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2. (a)
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3. (b)
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4. (c)
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## Determine the type
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1.
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1. `Num a => a`
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2. `Num a => (a, [Char])`
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3. `(Integer, [Char])`
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4. `Bool`
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5. `Int`
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6. `Bool`
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2. `Num a => a`
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3. `Num a => a -> a`
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4. `Fractional a => a`
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5. `[Char]`
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## Does it compile?
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1. The definition of `wahoo` tries to apply a `Num` to another `Num` which does not work. Either change `bigNum` to take an argument (`bigNum x = (^) 5 $ x ; wahoo = bigNum $ 10`) or fix `wahoo`, e.g. `wahoo = bigNum`
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2.Nothing wrong here.
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3. `c` tries to apply `5` to `b = 5` which does not work. It's also expected to take an argument in the definition of `d = c 200`. A fix could thus be: `c = a 10`.
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4. `c` is not defined for the definition of `b`.
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## Type variable or specific type constructor?
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1. /
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2. `zed` is fully polymorphic, `Zed` and `Blah` are concrete.
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3. `a` is fully polymorphic, `b` is constrained and `C` is concrete.
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4. `f` and `g` are fully polymorphic and `C` is concrete.
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## Write a type signature
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1. `functionH :: [a] -> a`
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2. `functionC :: (Ord a) => a -> a -> Bool`
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3. `functionS :: (a, b) -> b`
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## Given a type, write the function
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see src/defineFunc.hs
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## Fix it
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1. see src/sing.hs
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2. see src/sing.hs
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3. see src/arith3broken.hs
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## Type-Kwon-Do
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see src/typekwondo.hs
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