add anchors for chapter 6 (#378)

* add anchors for chapter 6

* Apply suggestions from code review

Co-authored-by: milesfrain <milesfrain@users.noreply.github.com>

Co-authored-by: milesfrain <milesfrain@users.noreply.github.com>

Author: ntwilson

exercises/chapter6/src/Data/Hashable.purs

@@ -17,40 +17,57 @@ import Data.Maybe (Maybe(..))
 import Data.String.CodeUnits (toCharArray)
 import Data.Tuple (Tuple(..))
 
+-- ANCHOR: Hashable
 newtype HashCode = HashCode Int
 
+instance hashCodeEq :: Eq HashCode where
+  eq (HashCode a) (HashCode b) = a == b
+
 hashCode :: Int -> HashCode
 hashCode h = HashCode (h `mod` 65535)
 
 class Eq a <= Hashable a where
   hash :: a -> HashCode
+-- ANCHOR_END: Hashable
 
 instance showHashCode :: Show HashCode where
   show (HashCode h) = "(HashCode " <> show h <> ")"
 
-derive instance eqHashCode :: Eq HashCode
-
+-- ANCHOR: combineHashes
 combineHashes :: HashCode -> HashCode -> HashCode
 combineHashes (HashCode h1) (HashCode h2) = hashCode (73 * h1 + 51 * h2)
+-- ANCHOR_END: combineHashes
 
+-- ANCHOR: hashEqual
 hashEqual :: forall a. Hashable a => a -> a -> Boolean
 hashEqual = eq `on` hash
+-- ANCHOR_END: hashEqual
 
+-- ANCHOR: hashChar
 instance hashChar :: Hashable Char where
   hash = hash <<< toCharCode
+-- ANCHOR_END: hashChar
 
+-- ANCHOR: hashString
 instance hashString :: Hashable String where
   hash = hash <<< toCharArray
+-- ANCHOR_END: hashString
 
+-- ANCHOR: hashInt
 instance hashInt :: Hashable Int where
   hash = hashCode
+-- ANCHOR_END: hashInt
 
+-- ANCHOR: hashBoolean
 instance hashBoolean :: Hashable Boolean where
   hash false = hashCode 0
   hash true  = hashCode 1
+-- ANCHOR_END: hashBoolean
 
+-- ANCHOR: hashArray
 instance hashArray :: Hashable a => Hashable (Array a) where
   hash = foldl combineHashes (hashCode 0) <<< map hash
+-- ANCHOR_END: hashArray
 
 instance hashMaybe :: Hashable a => Hashable (Maybe a) where
   hash Nothing = hashCode 0

exercises/chapter6/test/no-peeking/Solutions.purs

@@ -11,21 +11,25 @@ import Data.Maybe (Maybe(..))
 import Data.Monoid (power)
 import Data.Newtype (class Newtype, over2, wrap)
 
+-- ANCHOR: Point
 newtype Point
-  = Point
-  { x :: Number
-  , y :: Number
-  }
+      = Point
+      { x :: Number
+      , y :: Number
+      }
+-- ANCHOR_END: Point
 
 instance showPoint :: Show Point where
   show (Point p) =
     "(" <> show p.x <> ", " <> show p.y <> ")"
 
+-- ANCHOR: Complex
 newtype Complex
   = Complex
   { real :: Number
   , imaginary :: Number
   }
+-- ANCHOR_END: Complex
 
 instance showComplex :: Show Complex where
   show (Complex c) =
@@ -83,11 +87,13 @@ instance ringComplex :: Ring Complex where
   sub (Complex a) (Complex b) = Complex $ a - b
 -}
 
+-- ANCHOR: Shape
 data Shape
-  = Circle Point Number
-  | Rectangle Point Number Number
-  | Line Point Point
-  | Text Point String
+      = Circle Point Number
+      | Rectangle Point Number Number
+      | Line Point Point
+      | Text Point String
+-- ANCHOR_END: Shape
 
 derive instance genericShape :: Generic Shape _
 
@@ -102,8 +108,9 @@ instance showShape :: Show Shape where
   show (Text p s) = "(Text " <> show p <> " " <> show s <> ")"
 -}
 
-data NonEmpty a
-  = NonEmpty a (Array a)
+-- ANCHOR: NonEmpty
+data NonEmpty a = NonEmpty a (Array a)
+-- ANCHOR_END: NonEmpty
 
 instance eqNonEmpty :: Eq a => Eq (NonEmpty a) where
   eq (NonEmpty e1 a1) (NonEmpty e2 a2) = e1 == e2 && a1 == a2
@@ -125,9 +132,9 @@ instance functorNonEmpty :: Functor NonEmpty where
   map func (NonEmpty e1 a1) = NonEmpty (func e1) (map func a1)
 -}
 
-data Extended a
-  = Infinite
-  | Finite a
+-- ANCHOR: Extended
+data Extended a = Infinite | Finite a 
+-- ANCHOR_END: Extended
 
 derive instance eqExtended :: Eq a => Eq (Extended a)
 {-
@@ -156,10 +163,13 @@ instance foldableNonEmpty :: Foldable NonEmpty where
   foldl func st (NonEmpty val arr) = foldl func st ([ val ] <> arr)
   foldMap func (NonEmpty val arr) = foldMap func ([ val ] <> arr)
 
-data OneMore f a
-  = OneMore a (f a)
+-- ANCHOR: OneMore
+data OneMore f a = OneMore a (f a)
+-- ANCHOR_END: OneMore
 
+-- ANCHOR: OneMore_Foldable
 instance foldableOneMore :: Foldable f => Foldable (OneMore f) where
+-- ANCHOR_END: OneMore_Foldable
   foldr func st (OneMore val more) = func val lastB
     where
     lastB = foldr func st more
@@ -184,20 +194,28 @@ unsafeMaximum :: Partial => Array Int -> Int
 unsafeMaximum arr = case maximum arr of
   Just m -> m
 
-class
-  Monoid m <= Action m a where
-  act :: m -> a -> a
+-- ANCHOR: Action
+class Monoid m <= Action m a where
+      act :: m -> a -> a
+-- ANCHOR_END: Action
 
-newtype Multiply
-  = Multiply Int
+-- ANCHOR: Multiply
+newtype Multiply = Multiply Int
+-- ANCHOR_END: Multiply
 
+-- ANCHOR: semigroupMultiply
 instance semigroupMultiply :: Semigroup Multiply where
-  append (Multiply n) (Multiply m) = Multiply (n * m)
+      append (Multiply n) (Multiply m) = Multiply (n * m)
+-- ANCHOR_END: semigroupMultiply
 
+-- ANCHOR: monoidMultiply
 instance monoidMultiply :: Monoid Multiply where
-  mempty = Multiply 1
+      mempty = Multiply 1
+-- ANCHOR_END: monoidMultiply
 
+-- ANCHOR: Multiply_Action
 instance actionMultiplyInt :: Action Multiply Int where
+-- ANCHOR_END: Multiply_Action
   act (Multiply n) m = n * m
 
 {-
@@ -227,14 +245,17 @@ instance actionMultiplyInt :: Action Multiply Int where
 derive newtype instance showMultiply :: Show Multiply
 derive newtype instance eqMultiply :: Eq Multiply
 
+-- ANCHOR: actionMultiplyString
 instance actionMultiplyString :: Action Multiply String where
+-- ANCHOR_END: actionMultiplyString
   act (Multiply n) s = power s n
 
 instance actionArray :: Action m a => Action m (Array a) where
   act m arr = map (act m) arr
 
-newtype Self m
-  = Self m
+-- ANCHOR: Self
+newtype Self m = Self m
+-- ANCHOR_END: Self
 
 instance actionSelf :: Monoid m => Action m (Self m) where
   act m1 (Self m2) = Self (m1 <> m2)
@@ -250,11 +271,14 @@ arrayHasDuplicates arr =
   in
     length arr /= (length $ nubByEq hashAndValEqual arr)
 
-newtype Hour
-  = Hour Int
+-- ANCHOR: Hour
+newtype Hour = Hour Int
+-- ANCHOR_END: Hour
 
+-- ANCHOR: eqHour
 instance eqHour :: Eq Hour where
-  eq (Hour n) (Hour m) = mod n 12 == mod m 12
+      eq (Hour n) (Hour m) = mod n 12 == mod m 12
+-- ANCHOR_END: eqHour
 
 instance hashHour :: Hashable Hour where
   hash (Hour h) = hash $ mod h 12