[rotational-cipher] Implementation (#673)

config.json

@@ -724,6 +724,15 @@
         "prerequisites": [],
         "difficulty": 1,
         "topics": []
+      },
+      {
+        "slug": "rotational-cipher",
+        "name": "Rotational Cipher",
+        "uuid": "97aeb214-c566-498d-aa91-33358d105418",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1,
+        "topics": []
       }
     ]
   },

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

@@ -0,0 +1,29 @@
+# Instructions
+
+Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.
+
+The Caesar cipher is a simple shift cipher that relies on transposing all the letters in the alphabet using an integer key between `0` and `26`.
+Using a key of `0` or `26` will always yield the same output due to modular arithmetic.
+The letter is shifted for as many values as the value of the key.
+
+The general notation for rotational ciphers is `ROT + <key>`.
+The most commonly used rotational cipher is `ROT13`.
+
+A `ROT13` on the Latin alphabet would be as follows:
+
+```text
+Plain:  abcdefghijklmnopqrstuvwxyz
+Cipher: nopqrstuvwxyzabcdefghijklm
+```
+
+It is stronger than the Atbash cipher because it has 27 possible keys, and 25 usable keys.
+
+Ciphertext is written out in the same formatting as the input including spaces and punctuation.
+
+## Examples
+
+- ROT5  `omg` gives `trl`
+- ROT0  `c` gives `c`
+- ROT26 `Cool` gives `Cool`
+- ROT13 `The quick brown fox jumps over the lazy dog.` gives `Gur dhvpx oebja sbk whzcf bire gur ynml qbt.`
+- ROT13 `Gur dhvpx oebja sbk whzcf bire gur ynml qbt.` gives `The quick brown fox jumps over the lazy dog.`

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

@@ -0,0 +1,22 @@
+{
+  "authors": [
+    "habere-et-dispertire"
+  ],
+  "contributors": [
+    "m-dango"
+  ],
+  "files": {
+    "solution": [
+      "RotationalCipher.rakumod"
+    ],
+    "test": [
+      "rotational-cipher.rakutest"
+    ],
+    "example": [
+      ".meta/solutions/RotationalCipher.rakumod"
+    ]
+  },
+  "blurb": "Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Caesar_cipher"
+}

exercises/practice/rotational-cipher/.meta/solutions/RotationalCipher.rakumod

@@ -0,0 +1,6 @@
+unit module RotationalCipher;
+
+sub caesar-cipher ( Str :$text, Int :$shift-key --> Str ) is export {
+  $text.trans( 'A'..'Z' => rotate ( 'A'..'Z' ).Slip, $shift-key )
+          .trans: 'a'..'z' => rotate ( 'a'..'z' ).Slip, $shift-key;
+}

exercises/practice/rotational-cipher/.meta/solutions/rotational-cipher.rakutest

@@ -0,0 +1 @@
+../../rotational-cipher.rakutest

exercises/practice/rotational-cipher/.meta/template-data.yaml

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+unit: module
+
+properties:
+  rotate:
+    test: |-
+      my Str:D $template.=new;
+      if %case<input><shiftKey> != 13 {
+          $template = q:to/END/;
+          cmp-ok(
+              caesar-cipher( :text(%s), :shift-key(%s) ),
+              "eq",
+              %s,
+              %s,
+          );
+          END
+      }
+      else {
+          $template = q:to/END/;
+          subtest %4$s => {
+              cmp-ok(
+                  caesar-cipher( :text(%1$s), :shift-key(%2$s) ),
+                  "eq",
+                  %3$s,
+                  "encrypt",
+              );
+
+              cmp-ok(
+                  caesar-cipher( :text(%3$s), :shift-key(%2$s) ),
+                  "eq",
+                  %1$s,
+                  "decrypt",
+              );
+          }
+          END
+      }
+      sprintf($template, %case<input><text>.raku, %case<input><shiftKey>, %case<expected>.raku, %case<description>.raku);
+
+example: |-
+  sub caesar-cipher ( Str :$text, Int :$shift-key --> Str ) is export {
+    $text.trans( 'A'..'Z' => rotate ( 'A'..'Z' ).Slip, $shift-key )
+            .trans: 'a'..'z' => rotate ( 'a'..'z' ).Slip, $shift-key;
+  }
+
+stub: |-
+  sub caesar-cipher ( :$text, :$shift-key ) is export {
+  }

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

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+# 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.
+
+[74e58a38-e484-43f1-9466-877a7515e10f]
+description = "rotate a by 0, same output as input"
+
+[7ee352c6-e6b0-4930-b903-d09943ecb8f5]
+description = "rotate a by 1"
+
+[edf0a733-4231-4594-a5ee-46a4009ad764]
+description = "rotate a by 26, same output as input"
+
+[e3e82cb9-2a5b-403f-9931-e43213879300]
+description = "rotate m by 13"
+
+[19f9eb78-e2ad-4da4-8fe3-9291d47c1709]
+description = "rotate n by 13 with wrap around alphabet"
+
+[a116aef4-225b-4da9-884f-e8023ca6408a]
+description = "rotate capital letters"
+
+[71b541bb-819c-4dc6-a9c3-132ef9bb737b]
+description = "rotate spaces"
+
+[ef32601d-e9ef-4b29-b2b5-8971392282e6]
+description = "rotate numbers"
+
+[32dd74f6-db2b-41a6-b02c-82eb4f93e549]
+description = "rotate punctuation"
+
+[9fb93fe6-42b0-46e6-9ec1-0bf0a062d8c9]
+description = "rotate all letters"

exercises/practice/rotational-cipher/RotationalCipher.rakumod

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+unit module RotationalCipher;
+
+sub caesar-cipher ( :$text, :$shift-key ) is export {
+}

exercises/practice/rotational-cipher/rotational-cipher.rakutest

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+#!/usr/bin/env raku
+use Test;
+use lib $?FILE.IO.dirname;
+use RotationalCipher;
+
+cmp-ok( # begin: 74e58a38-e484-43f1-9466-877a7515e10f
+    caesar-cipher( :text("a"), :shift-key(0) ),
+    "eq",
+    "a",
+    "rotate a by 0, same output as input",
+); # end: 74e58a38-e484-43f1-9466-877a7515e10f
+
+cmp-ok( # begin: 7ee352c6-e6b0-4930-b903-d09943ecb8f5
+    caesar-cipher( :text("a"), :shift-key(1) ),
+    "eq",
+    "b",
+    "rotate a by 1",
+); # end: 7ee352c6-e6b0-4930-b903-d09943ecb8f5
+
+cmp-ok( # begin: edf0a733-4231-4594-a5ee-46a4009ad764
+    caesar-cipher( :text("a"), :shift-key(26) ),
+    "eq",
+    "a",
+    "rotate a by 26, same output as input",
+); # end: edf0a733-4231-4594-a5ee-46a4009ad764
+
+subtest "rotate m by 13" => { # begin: e3e82cb9-2a5b-403f-9931-e43213879300
+    cmp-ok(
+        caesar-cipher( :text("m"), :shift-key(13) ),
+        "eq",
+        "z",
+        "encrypt",
+    );
+
+    cmp-ok(
+        caesar-cipher( :text("z"), :shift-key(13) ),
+        "eq",
+        "m",
+        "decrypt",
+    );
+} # end: e3e82cb9-2a5b-403f-9931-e43213879300
+
+subtest "rotate n by 13 with wrap around alphabet" => { # begin: 19f9eb78-e2ad-4da4-8fe3-9291d47c1709
+    cmp-ok(
+        caesar-cipher( :text("n"), :shift-key(13) ),
+        "eq",
+        "a",
+        "encrypt",
+    );
+
+    cmp-ok(
+        caesar-cipher( :text("a"), :shift-key(13) ),
+        "eq",
+        "n",
+        "decrypt",
+    );
+} # end: 19f9eb78-e2ad-4da4-8fe3-9291d47c1709
+
+cmp-ok( # begin: a116aef4-225b-4da9-884f-e8023ca6408a
+    caesar-cipher( :text("OMG"), :shift-key(5) ),
+    "eq",
+    "TRL",
+    "rotate capital letters",
+); # end: a116aef4-225b-4da9-884f-e8023ca6408a
+
+cmp-ok( # begin: 71b541bb-819c-4dc6-a9c3-132ef9bb737b
+    caesar-cipher( :text("O M G"), :shift-key(5) ),
+    "eq",
+    "T R L",
+    "rotate spaces",
+); # end: 71b541bb-819c-4dc6-a9c3-132ef9bb737b
+
+cmp-ok( # begin: ef32601d-e9ef-4b29-b2b5-8971392282e6
+    caesar-cipher( :text("Testing 1 2 3 testing"), :shift-key(4) ),
+    "eq",
+    "Xiwxmrk 1 2 3 xiwxmrk",
+    "rotate numbers",
+); # end: ef32601d-e9ef-4b29-b2b5-8971392282e6
+
+cmp-ok( # begin: 32dd74f6-db2b-41a6-b02c-82eb4f93e549
+    caesar-cipher( :text("Let's eat, Grandma!"), :shift-key(21) ),
+    "eq",
+    "Gzo'n zvo, Bmviyhv!",
+    "rotate punctuation",
+); # end: 32dd74f6-db2b-41a6-b02c-82eb4f93e549
+
+subtest "rotate all letters" => { # begin: 9fb93fe6-42b0-46e6-9ec1-0bf0a062d8c9
+    cmp-ok(
+        caesar-cipher( :text("The quick brown fox jumps over the lazy dog."), :shift-key(13) ),
+        "eq",
+        "Gur dhvpx oebja sbk whzcf bire gur ynml qbt.",
+        "encrypt",
+    );
+
+    cmp-ok(
+        caesar-cipher( :text("Gur dhvpx oebja sbk whzcf bire gur ynml qbt."), :shift-key(13) ),
+        "eq",
+        "The quick brown fox jumps over the lazy dog.",
+        "decrypt",
+    );
+} # end: 9fb93fe6-42b0-46e6-9ec1-0bf0a062d8c9
+
+done-testing;