resistor-color-duo: Change to value :: (Color, Color) -> Int

exercises/resistor-color-duo/.meta/hints.md

@@ -0,0 +1,10 @@
+## Hints
+
+You need to implement the function
+
+```haskell
+value :: (Color, Color) -> Int
+```
+
+that only accepts two colors and produces the resistor's numeric value
+component of its resistance.

exercises/resistor-color-duo/README.md

@@ -27,6 +27,18 @@ brown-green should return 15
 brown-green-violet should return 15 too, ignoring the third color.
 
 
+## Hints
+
+You need to implement the function
+
+```haskell
+value :: (Color, Color) -> Int
+```
+
+that only accepts two colors and produces the resistor's numeric value
+component of its resistance.
+
+
 
 ## Getting Started
 

exercises/resistor-color-duo/examples/success-standard/src/ResistorColors.hs

@@ -11,19 +11,19 @@ data Color =
   | Violet
   | Grey
   | White
-  deriving (Eq, Show, Read)
+  deriving (Eq, Show)
 
-convert :: Color -> Int
-convert Black = 0
-convert Brown = 1
-convert Red = 2
-convert Orange = 3
-convert Yellow = 4
-convert Green = 5
-convert Blue = 6
-convert Violet = 7
-convert Grey = 8
-convert White = 9
+value1 :: Color -> Int
+value1 Black = 0
+value1 Brown = 1
+value1 Red = 2
+value1 Orange = 3
+value1 Yellow = 4
+value1 Green = 5
+value1 Blue = 6
+value1 Violet = 7
+value1 Grey = 8
+value1 White = 9
 
-value :: [Color] -> Int
-value = read . concatMap (show . convert) . take 2
+value :: (Color, Color) -> Int
+value (a, b) = 10 * value1 a + value1 b

exercises/resistor-color-duo/package.yaml

@@ -1,5 +1,5 @@
 name: resistor-color-duo
-version: 2.1.0.2
+version: 2.1.0.3
 
 dependencies:
   - base

exercises/resistor-color-duo/src/ResistorColors.hs

@@ -11,7 +11,7 @@ data Color =
   | Violet
   | Grey
   | White
-  deriving (Eq, Show, Read)
+  deriving (Eq, Show)
 
-value :: [Color] -> Int
-value cs = error "You need to implement this function."
+value :: (Color, Color) -> Int
+value (a, b) = error "You need to implement this function."

exercises/resistor-color-duo/test/Tests.hs

@@ -20,29 +20,25 @@ specs = describe "value" $ for_ cases test
         assertion   = value input `shouldBe` expected
 
 data Case = Case { description :: String
-                 , input       :: [Color]
+                 , input       :: (Color, Color)
                  , expected    :: Int
                  }
 
 cases :: [Case]
 cases = [ Case { description = "Brown and black"
-               , input       = [Brown, Black]
+               , input       = (Brown, Black)
                , expected    = 10
                }
         , Case { description = "Blue and grey"
-               , input       = [Blue, Grey]
+               , input       = (Blue, Grey)
                , expected    = 68
                }
         , Case { description = "Yellow and violet"
-               , input       = [Yellow, Violet]
+               , input       = (Yellow, Violet)
                , expected    = 47
                }
         , Case { description = "Orange and orange"
-               , input       = [Orange, Orange]
+               , input       = (Orange, Orange)
                , expected    = 33
                }
-        , Case { description = "Ignore additional colors"
-               , input       = [Green, Brown, Orange]
-               , expected    = 51
-               }
         ]