atbash-cipher: implement exercise

config.json

@@ -376,6 +376,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 1
+      },
+      {
+        "slug": "atbash-cipher",
+        "name": "Atbash Cipher",
+        "uuid": "660bfdb0-dd6d-494b-8a15-070f6dbe233b",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ]
   },

exercises/practice/atbash-cipher/.docs/instructions.md

@@ -0,0 +1,27 @@
+# Instructions
+
+Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
+
+The Atbash cipher is a simple substitution cipher that relies on transposing all the letters in the alphabet such that the resulting alphabet is backwards.
+The first letter is replaced with the last letter, the second with the second-last, and so on.
+
+An Atbash cipher for the Latin alphabet would be as follows:
+
+```text
+Plain:  abcdefghijklmnopqrstuvwxyz
+Cipher: zyxwvutsrqponmlkjihgfedcba
+```
+
+It is a very weak cipher because it only has one possible key, and it is a simple mono-alphabetic substitution cipher.
+However, this may not have been an issue in the cipher's time.
+
+Ciphertext is written out in groups of fixed length, the traditional group size being 5 letters, leaving numbers unchanged, and punctuation is excluded.
+This is to make it harder to guess things based on word boundaries.
+All text will be encoded as lowercase letters.
+
+## Examples
+
+- Encoding `test` gives `gvhg`
+- Encoding `x123 yes` gives `c123b vh`
+- Decoding `gvhg` gives `test`
+- Decoding `gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt` gives `thequickbrownfoxjumpsoverthelazydog`

exercises/practice/atbash-cipher/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "dreig"
+  ],
+  "files": {
+    "solution": [
+      "atbashCipher.u"
+    ],
+    "test": [
+      "atbashCipher.test.u"
+    ],
+    "example": [
+      ".meta/examples/atbashCipher.example.u"
+    ]
+  },
+  "blurb": "Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Atbash"
+}

exercises/practice/atbash-cipher/.meta/examples/atbashCipher.example.u

@@ -0,0 +1,29 @@
+atbashCipher.encodeSingle : Char -> Char
+atbashCipher.encodeSingle c = Map.get c mapping |> Optional.getOrElse c
+
+atbashCipher.mapping : Map Char Char
+atbashCipher.mapping =
+  use Char rangeClosed
+  List.zip (rangeClosed ?a ?z) (rangeClosed ?a ?z |> List.reverse)
+    |> Map.fromList
+
+atbashCipher.encode : Text -> Text
+atbashCipher.encode input =
+  use List map
+  toCharList input
+    |> List.filter isAlphaNum
+    |> map ascii.toLower
+    |> map encodeSingle
+    |> List.chunk 5
+    |> map fromCharList
+    |> Text.join " "
+
+atbashCipher.decode : Text -> Text
+atbashCipher.decode input =
+  use List map
+  toCharList input
+    |> List.filter isAlphaNum
+    |> map ascii.toLower
+    |> map encodeSingle
+    |> fromCharList
+

exercises/practice/atbash-cipher/.meta/testAnnotation.json

@@ -0,0 +1,58 @@
+[
+  {
+    "test_code": "atbashCipher.test.ex1 = let\n  actual = encode \"yes\"\n  expected = \"bvh\"\n  Test.label \"encode yes\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex1"
+  },
+  {
+    "test_code": "atbashCipher.test.ex2 = let\n  actual = encode \"no\"\n  expected = \"ml\"\n  Test.label \"encode no\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex2"
+  },
+  {
+    "test_code": "atbashCipher.test.ex3 = let\n  actual = encode \"OMG\"\n  expected = \"lnt\"\n  Test.label \"encode OMG\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex3"
+  },
+  {
+    "test_code": "atbashCipher.test.ex4 = let\n  actual = encode \"O M G\"\n  expected = \"lnt\"\n  Test.label \"encode spaces\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex4"
+  },
+  {
+    "test_code": "atbashCipher.test.ex5 = let\n  actual = encode \"mindblowingly\"\n  expected = \"nrmwy oldrm tob\"\n  Test.label \"encode mindblowingly\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex5"
+  },
+  {
+    "test_code": "atbashCipher.test.ex6 = let\n  actual = encode \"Testing,1 2 3, testing.\"\n  expected = \"gvhgr mt123 gvhgr mt\"\n  Test.label \"encode numbers\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex6"
+  },
+  {
+    "test_code": "atbashCipher.test.ex7 = let\n  actual = encode \"Truth is fiction.\"\n  expected = \"gifgs rhurx grlm\"\n  Test.label \"encode deep thought\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex7"
+  },
+  {
+    "test_code": "atbashCipher.test.ex8 = let\n  actual = encode \"The quick brown fox jumps over the lazy dog.\"\n  expected = \"gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt\"\n  Test.label \"encode all the letters\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex8"
+  },
+  {
+    "test_code": "atbashCipher.test.ex9 = let\n  actual = decode \"vcvix rhn\"\n  expected = \"exercism\"\n  Test.label \"decode exercism\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex9"
+  },
+  {
+    "test_code": "atbashCipher.test.ex10 = let\n  actual = decode \"zmlyh gzxov rhlug vmzhg vkkrm thglm v\"\n  expected = \"anobstacleisoftenasteppingstone\"\n  Test.label \"decode a sentence\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex10"
+  },
+  {
+    "test_code": "atbashCipher.test.ex11 = let\n  actual = decode \"gvhgr mt123 gvhgr mt\"\n  expected = \"testing123testing\"\n  Test.label \"decode numbers\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex11"
+  },
+  {
+    "test_code": "atbashCipher.test.ex12 = let\n  actual = decode \"gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt\"\n  expected = \"thequickbrownfoxjumpsoverthelazydog\"\n  Test.label \"decode all the letters\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex12"
+  },
+  {
+    "test_code": "atbashCipher.test.ex13 = let\n  actual = decode \"vc vix    r hn\"\n  expected = \"exercism\"\n  Test.label \"decode with too many spaces\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex13"
+  },
+  {
+    "test_code": "atbashCipher.test.ex14 = let\n  actual = decode \"zmlyhgzxovrhlugvmzhgvkkrmthglmv\"\n  expected = \"anobstacleisoftenasteppingstone\"\n  Test.label \"decode with no spaces\" <| Test.expect (actual == expected)",
+    "name": "atbashCipher.test.ex14"
+  }
+]

exercises/practice/atbash-cipher/.meta/testLoader.md

@@ -0,0 +1,9 @@
+# Testing transcript for atbash-cipher exercise
+
+```ucm
+.> load ./atbashCipher.u
+.> add
+.> load ./atbashCipher.test.u
+.> add
+.> move.term atbashCipher.tests tests
+```

exercises/practice/atbash-cipher/.meta/tests.toml

@@ -0,0 +1,52 @@
+# 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.
+
+[2f47ebe1-eab9-4d6b-b3c6-627562a31c77]
+description = "encode -> encode yes"
+
+[b4ffe781-ea81-4b74-b268-cc58ba21c739]
+description = "encode -> encode no"
+
+[10e48927-24ab-4c4d-9d3f-3067724ace00]
+description = "encode -> encode OMG"
+
+[d59b8bc3-509a-4a9a-834c-6f501b98750b]
+description = "encode -> encode spaces"
+
+[31d44b11-81b7-4a94-8b43-4af6a2449429]
+description = "encode -> encode mindblowingly"
+
+[d503361a-1433-48c0-aae0-d41b5baa33ff]
+description = "encode -> encode numbers"
+
+[79c8a2d5-0772-42d4-b41b-531d0b5da926]
+description = "encode -> encode deep thought"
+
+[9ca13d23-d32a-4967-a1fd-6100b8742bab]
+description = "encode -> encode all the letters"
+
+[bb50e087-7fdf-48e7-9223-284fe7e69851]
+description = "decode -> decode exercism"
+
+[ac021097-cd5d-4717-8907-b0814b9e292c]
+description = "decode -> decode a sentence"
+
+[18729de3-de74-49b8-b68c-025eaf77f851]
+description = "decode -> decode numbers"
+
+[0f30325f-f53b-415d-ad3e-a7a4f63de034]
+description = "decode -> decode all the letters"
+
+[39640287-30c6-4c8c-9bac-9d613d1a5674]
+description = "decode -> decode with too many spaces"
+
+[b34edf13-34c0-49b5-aa21-0768928000d5]
+description = "decode -> decode with no spaces"

exercises/practice/atbash-cipher/atbashCipher.test.u

@@ -0,0 +1,87 @@
+atbashCipher.test.ex1 = let
+  actual = encode "yes"
+  expected = "bvh"
+  Test.label "encode yes" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex2 = let
+  actual = encode "no"
+  expected = "ml"
+  Test.label "encode no" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex3 = let
+  actual = encode "OMG"
+  expected = "lnt"
+  Test.label "encode OMG" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex4 = let
+  actual = encode "O M G"
+  expected = "lnt"
+  Test.label "encode spaces" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex5 = let
+  actual = encode "mindblowingly"
+  expected = "nrmwy oldrm tob"
+  Test.label "encode mindblowingly" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex6 = let
+  actual = encode "Testing,1 2 3, testing."
+  expected = "gvhgr mt123 gvhgr mt"
+  Test.label "encode numbers" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex7 = let
+  actual = encode "Truth is fiction."
+  expected = "gifgs rhurx grlm"
+  Test.label "encode deep thought" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex8 = let
+  actual = encode "The quick brown fox jumps over the lazy dog."
+  expected = "gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt"
+  Test.label "encode all the letters" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex9 = let
+  actual = decode "vcvix rhn"
+  expected = "exercism"
+  Test.label "decode exercism" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex10 = let
+  actual = decode "zmlyh gzxov rhlug vmzhg vkkrm thglm v"
+  expected = "anobstacleisoftenasteppingstone"
+  Test.label "decode a sentence" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex11 = let
+  actual = decode "gvhgr mt123 gvhgr mt"
+  expected = "testing123testing"
+  Test.label "decode numbers" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex12 = let
+  actual = decode "gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt"
+  expected = "thequickbrownfoxjumpsoverthelazydog"
+  Test.label "decode all the letters" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex13 = let
+  actual = decode "vc vix    r hn"
+  expected = "exercism"
+  Test.label "decode with too many spaces" <| Test.expect (actual == expected)
+
+atbashCipher.test.ex14 = let
+  actual = decode "zmlyhgzxovrhlugvmzhgvkkrmthglmv"
+  expected = "anobstacleisoftenasteppingstone"
+  Test.label "decode with no spaces" <| Test.expect (actual == expected)
+
+test> atbashCipher.tests = runAll [ 
+  atbashCipher.test.ex1,
+  atbashCipher.test.ex2,
+  atbashCipher.test.ex3,
+  atbashCipher.test.ex4,
+  atbashCipher.test.ex5,
+  atbashCipher.test.ex6,
+  atbashCipher.test.ex7,
+  atbashCipher.test.ex8,
+  atbashCipher.test.ex9,
+  atbashCipher.test.ex10,
+  atbashCipher.test.ex11,
+  atbashCipher.test.ex12,
+  atbashCipher.test.ex13,
+  atbashCipher.test.ex14,
+]
+

exercises/practice/atbash-cipher/atbashCipher.u

@@ -0,0 +1,6 @@
+atbashCipher.encode : Text -> Text
+atbashCipher.encode input = todo "implement encode"
+
+atbashCipher.decode : Text -> Text
+atbashCipher.decode input = todo "implement decode"
+