Add crypto-square exercise (#153)

* Add crypto-square exercise

* Tests have input and expectation on separate lines

* Omit return keyword in single line functions

config.json

@@ -432,6 +432,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "crypto-square",
+        "name": "Crypto Square",
+        "uuid": "0a9050d7-01dc-4c69-8f85-72d8c19b876a",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "spiral-matrix",
         "name": "Spiral Matrix",

exercises/practice/crypto-square/.docs/instructions.md

@@ -0,0 +1,71 @@
+# Instructions
+
+Implement the classic method for composing secret messages called a square code.
+
+Given an English text, output the encoded version of that text.
+
+First, the input is normalized: the spaces and punctuation are removed from the English text and the message is down-cased.
+
+Then, the normalized characters are broken into rows.
+These rows can be regarded as forming a rectangle when printed with intervening newlines.
+
+For example, the sentence
+
+```text
+"If man was meant to stay on the ground, god would have given us roots."
+```
+
+is normalized to:
+
+```text
+"ifmanwasmeanttostayonthegroundgodwouldhavegivenusroots"
+```
+
+The plaintext should be organized into a rectangle as square as possible.
+The size of the rectangle should be decided by the length of the message.
+
+If `c` is the number of columns and `r` is the number of rows, then for the rectangle `r` x `c` find the smallest possible integer `c` such that:
+
+- `r * c >= length of message`,
+- and `c >= r`,
+- and `c - r <= 1`.
+
+Our normalized text is 54 characters long, dictating a rectangle with `c = 8` and `r = 7`:
+
+```text
+"ifmanwas"
+"meanttos"
+"tayonthe"
+"groundgo"
+"dwouldha"
+"vegivenu"
+"sroots  "
+```
+
+The coded message is obtained by reading down the columns going left to right.
+
+The message above is coded as:
+
+```text
+"imtgdvsfearwermayoogoanouuiontnnlvtwttddesaohghnsseoau"
+```
+
+Output the encoded text in chunks that fill perfect rectangles `(r X c)`, with `c` chunks of `r` length, separated by spaces.
+For phrases that are `n` characters short of the perfect rectangle, pad each of the last `n` chunks with a single trailing space.
+
+```text
+"imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau "
+```
+
+Notice that were we to stack these, we could visually decode the ciphertext back in to the original message:
+
+```text
+"imtgdvs"
+"fearwer"
+"mayoogo"
+"anouuio"
+"ntnnlvt"
+"wttddes"
+"aohghn "
+"sseoau "
+```

exercises/practice/crypto-square/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "crypto-square.wren"
+    ],
+    "test": [
+      "crypto-square.spec.wren"
+    ],
+    "example": [
+      ".meta/proof.ci.wren"
+    ]
+  },
+  "blurb": "Implement the classic method for composing secret messages called a square code.",
+  "source": "J Dalbey's Programming Practice problems",
+  "source_url": "https://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html"
+}

exercises/practice/crypto-square/.meta/proof.ci.wren

@@ -0,0 +1,48 @@
+class CryptoSquare {
+  static columns(n) {
+    var c = 0
+    while (c * c < n) {
+      c = c + 1
+    }
+    return c
+  }
+
+  static rows(n, c) {
+    var r = c - 1
+    if (r * c < n) {
+      r = r + 1
+    }
+    // r * c >= n
+    return r
+  }
+
+  static ciphertext(plaintext) {
+    var toLower = Fn.new {|codePoint| ((65..90).contains(codePoint)) ? codePoint + 32 : codePoint }
+
+    var isAlphanumeric = Fn.new {|codePoint| (48..57).contains(codePoint) || (65..90).contains(codePoint) || (97..122).contains(codePoint) }
+
+    var toString = Fn.new {|codePoint| String.fromCodePoint(codePoint) }
+
+    var codePoints = plaintext.codePoints.map(toLower).where(isAlphanumeric).toList
+
+    var n = codePoints.count
+    if (n <= 1) {
+      return codePoints.map(toString).join()
+    }
+
+    var c = columns(n)
+    var r = rows(n, c)
+    var buffer = List.filled((r + 1) * c - 1, 32)
+    var index = 0
+    for (i in 0...r) {
+      for (j in 0...c) {
+        buffer[j * (r + 1) + i] = codePoints[index]
+        index = index + 1
+        if (index == n) {
+          break
+        }
+      }
+    }
+    return buffer.map(toString).join()
+  }
+}

exercises/practice/crypto-square/.meta/tests.toml

@@ -0,0 +1,34 @@
+# 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.
+
+[407c3837-9aa7-4111-ab63-ec54b58e8e9f]
+description = "empty plaintext results in an empty ciphertext"
+
+[aad04a25-b8bb-4304-888b-581bea8e0040]
+description = "normalization results in empty plaintext"
+
+[64131d65-6fd9-4f58-bdd8-4a2370fb481d]
+description = "Lowercase"
+
+[63a4b0ed-1e3c-41ea-a999-f6f26ba447d6]
+description = "Remove spaces"
+
+[1b5348a1-7893-44c1-8197-42d48d18756c]
+description = "Remove punctuation"
+
+[8574a1d3-4a08-4cec-a7c7-de93a164f41a]
+description = "9 character plaintext results in 3 chunks of 3 characters"
+
+[a65d3fa1-9e09-43f9-bcec-7a672aec3eae]
+description = "8 character plaintext results in 3 chunks, the last one with a trailing space"
+
+[fbcb0c6d-4c39-4a31-83f6-c473baa6af80]
+description = "54 character plaintext results in 7 chunks, the last two with trailing spaces"

exercises/practice/crypto-square/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

exercises/practice/crypto-square/crypto-square.spec.wren

@@ -0,0 +1,52 @@
+import "./crypto-square" for CryptoSquare
+import "wren-testie/testie" for Testie, Expect
+
+Testie.test("CryptoSquare.ciphertext()") { |do, skip|
+  do.test("empty plaintext results in an empty ciphertext") {
+    var phrase = ""
+    var expect = ""
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("normalization results in empty plaintext") {
+    var phrase = "... --- ..."
+    var expect = ""
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("Lowercase") {
+    var phrase = "A"
+    var expect = "a"
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("Remove spaces") {
+    var phrase = "  b "
+    var expect = "b"
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("Remove punctuation") {
+    var phrase = "@1,\%!"
+    var expect = "1"
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("9 character plaintext results in 3 chunks of 3 characters") {
+    var phrase = "This is fun!"
+    var expect = "tsf hiu isn"
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("8 character plaintext results in 3 chunks, the last one with a trailing space") {
+    var phrase = "Chill out."
+    var expect = "clu hlt io "
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+
+  skip.test("54 character plaintext results in 7 chunks, the last two with trailing spaces") {
+    var phrase = "If man was meant to stay on the ground, god would have given us roots."
+    var expect = "imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau "
+    Expect.value(CryptoSquare.ciphertext(phrase)).toEqual(expect)
+  }
+}

exercises/practice/crypto-square/crypto-square.wren

@@ -0,0 +1,5 @@
+class CryptoSquare {
+  static ciphertext(plaintext) {
+    Fiber.abort("Remove this statement and implement this function")
+  }
+}

exercises/practice/crypto-square/package.wren

@@ -0,0 +1,14 @@
+import "wren-package" for WrenPackage, Dependency
+import "os" for Process
+
+class Package is WrenPackage {
+  construct new() {}
+  name { "exercism/crypto-square" }
+  dependencies {
+    return [
+      Dependency.new("wren-testie", "0.3.0", "https://github.com/joshgoebel/wren-testie.git")
+    ]
+  }
+}
+
+Package.new().default()