Update my "Validating numbers into words" solution from ch14

Author: dwayne

ch14/chex/WordNumber.hs

@@ -1,8 +1,13 @@
-module WordNumber where
+module WordNumber
+  ( digitToWord
+  , digits
+  , wordNumber
+  ) where
 
 import Data.List (intersperse)
 import Data.Maybe (fromJust)
 
+
 digitToWord :: Int -> Maybe String
 digitToWord 0 = Just "zero"
 digitToWord 1 = Just "one"
@@ -16,10 +21,12 @@ digitToWord 8 = Just "eight"
 digitToWord 9 = Just "nine"
 digitToWord _ = Nothing
 
+
 digits :: Int -> [Int]
 digits n
   | n == 0    = []
   | otherwise = digits (div n 10) ++ [mod n 10]
 
+
 wordNumber :: Int -> String
 wordNumber = concat . intersperse "-" . map (fromJust . digitToWord) . digits

ch14/chex/WordNumberTest.hs

@@ -3,6 +3,7 @@ module WordNumberTest where
 import Test.Hspec
 import WordNumber (digitToWord, digits, wordNumber)
 
+
 main :: IO ()
 main = hspec $ do
   describe "digitToWord" $ do

ch14/chex/chex.cabal

@@ -1,13 +1,12 @@
 name:                chex
 version:             0.1.0.0
-synopsis:            Initial project template from stack
-description:         Please see README.md
+description:         Chapter Exercises
 homepage:            https://github.com/dwayne/chex#readme
 license:             BSD3
 license-file:        LICENSE
 author:              Dwayne Crooks
 maintainer:          me@dwaynecrooks.com
-copyright:           2016 Dwayne Crooks
+copyright:           2017 Dwayne Crooks
 category:            Text
 build-type:          Simple
 cabal-version:       >=1.10
@@ -16,6 +15,7 @@ library
   hs-source-dirs:       .
   default-language:     Haskell2010
   ghc-options:          -Wall -fwarn-tabs
-  exposed-modules:      WordNumberTest
+  exposed-modules:      WordNumber
+                      , WordNumberTest
   build-depends:        base >= 4.7 && < 5
                       , hspec

ch14/chex/stack.yaml

@@ -15,7 +15,7 @@
 # resolver:
 #  name: custom-snapshot
 #  location: "./custom-snapshot.yaml"
-resolver: lts-5.17
+resolver: lts-8.2
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.
@@ -52,7 +52,7 @@ extra-package-dbs: []
 #
 # Require a specific version of stack, using version ranges
 # require-stack-version: -any # Default
-# require-stack-version: ">=1.1"
+# require-stack-version: ">=1.3"
 #
 # Override the architecture used by stack, especially useful on Windows
 # arch: i386
@@ -63,4 +63,4 @@ extra-package-dbs: []
 # extra-lib-dirs: [/path/to/dir]
 #
 # Allow a newer minor version of GHC than the snapshot specifies
-# compiler-check: newer-minor
+# compiler-check: newer-minor