implemented getNumRungs

src/Abacus.hs

@@ -24,7 +24,7 @@ License along with this program.  If not, see
 
 -}
 
-module Abacus (Abacus, newAbacus, getNumBeads) where
+module Abacus (Abacus, newAbacus, getNumBeads, getNumRungs) where
 
 import Abacus.Internal
 
@@ -40,8 +40,12 @@ newAbacus beads rungs = if beads < 1 || rungs < 1
   then Nothing
   else Just $ Abacus beads $ replicate rungs 0
 
--- | Returns the number of beads per rung in an abacus
+-- | Returns the number of beads per rung in an "Abacus"
 getNumBeads :: Abacus -> Int
 getNumBeads = abacusNumBeads
 
+-- | Returns the number of rungs in an "Abacus"
+getNumRungs :: Abacus -> Int
+getNumRungs = length . abacusRungs
+
 --jl

src/Abacus/Internal.hs

@@ -36,7 +36,7 @@ module Abacus.Internal (Abacus (..)) where
 data Abacus = Abacus
   { abacusNumBeads :: Int
   -- ^ The number of beads per rung of the abacus
-  , abacusRows :: [Int]
+  , abacusRungs :: [Int]
   -- ^ The number of beads slid across each rung
   } deriving (Eq, Show)
 

test/AbacusSpec.hs

@@ -31,6 +31,7 @@ spec :: Spec
 spec = describe "Abacus" $ do
   newAbacusSpec
   getNumBeadsSpec
+  getNumRungsSpec
 
 newAbacusSpec :: Spec
 newAbacusSpec = describe "newAbacusSpec" $ mapM_
@@ -58,4 +59,18 @@ getNumBeadsSpec = describe "getNumBeads" $ mapM_
     tenBeads = build 10
     build n = fromJust $ newAbacus n 10
 
+getNumRungsSpec :: Spec
+getNumRungsSpec = describe "getNumRungs" $ mapM_
+  ( \(desc, input, expected) -> context desc $ let
+    actual = getNumRungs input
+    in it ("should be " ++ show expected) $
+      actual `shouldBe` expected
+  )
+  [ ( "one rung",  oneRung,  1  )
+  , ( "ten rungs", tenRungs, 10 )
+  ] where
+    oneRung = build 1
+    tenRungs = build 10
+    build n = fromJust $ newAbacus 10 n
+
 --jl