Added reverse-string exercise

config.json

@@ -122,6 +122,18 @@
           "expressions"
         ]
       },
+      {
+        "slug": "reverse-string",
+        "name": "Reverse String",
+        "uuid": "8ed8f6d7-ee0a-4d61-99b5-c8b86f01c5de",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1,
+        "topics": [
+          "strings",
+          "lists"
+        ]
+      },
       {
         "slug": "space-age",
         "name": "Space Age",

exercises/practice/reverse-string/.docs/instructions.md

@@ -0,0 +1,7 @@
+# Instructions
+
+Reverse a string
+
+For example:
+input: "cool"
+output: "looc"

exercises/practice/reverse-string/.meta/config.json

@@ -0,0 +1,23 @@
+{
+  "authors": [
+    "cdimitroulas"
+  ],
+  "files": {
+    "solution": [
+      "src/ReverseString.hs",
+      "package.yaml"
+    ],
+    "test": [
+      "test/Tests.hs"
+    ],
+    "example": [
+      ".meta/examples/success-standard/src/ReverseString.hs"
+    ],
+    "invalidator": [
+      "stack.yaml"
+    ]
+  },
+  "blurb": "Reverse a string.",
+  "source": "Introductory challenge to reverse an input string",
+  "source_url": "https://medium.freecodecamp.org/how-to-reverse-a-string-in-javascript-in-3-different-ways-75e4763c68cb"
+}

exercises/practice/reverse-string/.meta/examples/success-standard/package.yaml

@@ -0,0 +1,16 @@
+name: reverse-string
+
+dependencies:
+  - base
+
+library:
+  exposed-modules: ReverseString
+  source-dirs: src
+
+tests:
+  test:
+    main: Tests.hs
+    source-dirs: test
+    dependencies:
+      - reverse-string
+      - hspec

exercises/practice/reverse-string/.meta/examples/success-standard/src/ReverseString.hs

@@ -0,0 +1,4 @@
+module ReverseString (reverseString) where
+
+reverseString :: String -> String
+reverseString input = reverse input

exercises/practice/reverse-string/.meta/tests.toml

@@ -0,0 +1,28 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[c3b7d806-dced-49ee-8543-933fd1719b1c]
+description = "an empty string"
+
+[01ebf55b-bebb-414e-9dec-06f7bb0bee3c]
+description = "a word"
+
+[0f7c07e4-efd1-4aaa-a07a-90b49ce0b746]
+description = "a capitalized word"
+
+[71854b9c-f200-4469-9f5c-1e8e5eff5614]
+description = "a sentence with punctuation"
+
+[1f8ed2f3-56f3-459b-8f3e-6d8d654a1f6c]
+description = "a palindrome"
+
+[b9e7dec1-c6df-40bd-9fa3-cd7ded010c4c]
+description = "an even-sized word"

exercises/practice/reverse-string/package.yaml

@@ -0,0 +1,21 @@
+name: reverse-string
+version: 0.1.0.0
+
+dependencies:
+  - base
+
+library:
+  exposed-modules: ReverseString
+  source-dirs: src
+  ghc-options: -Wall
+  # dependencies:
+  # - foo       # List here the packages you
+  # - bar       # want to use in your solution.
+
+tests:
+  test:
+    main: Tests.hs
+    source-dirs: test
+    dependencies:
+      - reverse-string
+      - hspec

exercises/practice/reverse-string/src/ReverseString.hs

@@ -0,0 +1,4 @@
+module ReverseString (reverseString) where
+
+reverseString :: String -> String
+reverseString input = error "You need to implement this funciton."

exercises/practice/reverse-string/stack.yaml

@@ -0,0 +1 @@
+resolver: lts-20.18

exercises/practice/reverse-string/stack.yaml.lock

@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 9fa4bece7acfac1fc7930c5d6e24606004b09e80aa0e52e9f68b148201008db9
+    size: 649606
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/20/18.yaml
+  original: lts-20.18

exercises/practice/reverse-string/test/Tests.hs

@@ -0,0 +1,51 @@
+{-# LANGUAGE RecordWildCards #-}
+
+import Data.Foldable     (for_)
+import Test.Hspec        (Spec, describe, it, shouldBe)
+import Test.Hspec.Runner (configFailFast, defaultConfig, hspecWith)
+
+import ReverseString (reverseString)
+
+main :: IO ()
+main = hspecWith defaultConfig {configFailFast = True} specs
+
+specs :: Spec
+specs = describe "reverseString" $ for_ cases test
+  where
+
+    test Case{..} = it explanation assertion
+      where
+        explanation = unwords [show input, "-", description]
+        assertion   = reverseString input `shouldBe` expected
+
+data Case = Case { description :: String
+                 , input       :: String
+                 , expected    :: String
+                 }
+
+cases :: [Case]
+cases = [ Case { description = "empty string"
+               , input       = ""
+               , expected    = ""
+               }
+        , Case { description = "a word"
+               , input       = "robot"
+               , expected    = "tobor"
+               }
+        , Case { description = "a capitalized word"
+               , input       = "Ramen"
+               , expected    = "nemaR"
+               }
+        , Case { description = "a sentence with punctuation"
+               , input       = "I am hungry!"
+               , expected    = "!yrgnuh ma I"
+               }
+        , Case { description = "a palindrome"
+               , input       = "racecar"
+               , expected    = "racecar"
+               }
+        , Case { description = "an even-sized word"
+               , input       = "drawer"
+               , expected    = "reward"
+               }
+        ]