Add crypto-square exercise

config.json

@@ -323,6 +323,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "crypto-square",
+        "name": "Crypto Square",
+        "uuid": "b3e52a1c-d51f-4a86-8e3c-6bc2c89daa97",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
+      },
       {
         "slug": "diamond",
         "name": "Diamond",

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/Example.roc

@@ -0,0 +1,27 @@
+module [ciphertext]
+
+ciphertext : Str -> Result Str _
+ciphertext = \text ->
+    chars =
+        text
+        |> Str.toUtf8
+        |> List.joinMap \char ->
+            if (char >= 'a' && char <= 'z') || (char >= '0' && char <= '9') then
+                [char]
+            else if char >= 'A' && char <= 'Z' then
+                [char - 'A' + 'a']
+            else
+                []
+
+    length = List.len chars
+    width = length |> Num.toF64 |> Num.sqrt |> Num.ceiling |> Num.toU64
+    rows = chars |> List.chunksOf width
+
+    List.range { start: At 0, end: Before width }
+    |> List.map \column ->
+        rows
+        |> List.map \row ->
+            row |> List.get column |> Result.withDefault ' '
+    |> List.intersperse [' ']
+    |> List.join
+    |> Str.fromUtf8

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

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "ageron"
+  ],
+  "files": {
+    "solution": [
+      "CryptoSquare.roc"
+    ],
+    "test": [
+      "crypto-square-test.roc"
+    ],
+    "example": [
+      ".meta/Example.roc"
+    ]
+  },
+  "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/template.j2

@@ -0,0 +1,15 @@
+{%- import "generator_macros.j2" as macros with context -%}
+{{ macros.canonical_ref() }}
+{{ macros.header() }}
+
+import {{ exercise | to_pascal }} exposing [{{ cases[0]["property"] | to_camel }}]
+
+{% for case in cases -%}
+# {{ case["description"] }}
+expect
+    text = {{ case["input"]["plaintext"] | to_roc }}
+    result = {{ case["property"] | to_camel }} text
+    expected = Ok {{ case["expected"] | to_roc }}
+    result == expected
+
+{% endfor %}

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/CryptoSquare.roc

@@ -0,0 +1,5 @@
+module [ciphertext]
+
+ciphertext : Str -> Result Str _
+ciphertext = \text ->
+    crash "Please implement the 'ciphertext' function"

exercises/practice/crypto-square/crypto-square-test.roc

@@ -0,0 +1,68 @@
+# These tests are auto-generated with test data from:
+# https://github.com/exercism/problem-specifications/tree/main/exercises/crypto-square/canonical-data.json
+# File last updated on 2024-10-10
+app [main] {
+    pf: platform "https://github.com/roc-lang/basic-cli/releases/download/0.15.0/SlwdbJ-3GR7uBWQo6zlmYWNYOxnvo8r6YABXD-45UOw.tar.br",
+}
+
+main =
+    Task.ok {}
+
+import CryptoSquare exposing [ciphertext]
+
+# empty plaintext results in an empty ciphertext
+expect
+    text = ""
+    result = ciphertext text
+    expected = Ok ""
+    result == expected
+
+# normalization results in empty plaintext
+expect
+    text = "... --- ..."
+    result = ciphertext text
+    expected = Ok ""
+    result == expected
+
+# Lowercase
+expect
+    text = "A"
+    result = ciphertext text
+    expected = Ok "a"
+    result == expected
+
+# Remove spaces
+expect
+    text = "  b "
+    result = ciphertext text
+    expected = Ok "b"
+    result == expected
+
+# Remove punctuation
+expect
+    text = "@1,%!"
+    result = ciphertext text
+    expected = Ok "1"
+    result == expected
+
+# 9 character plaintext results in 3 chunks of 3 characters
+expect
+    text = "This is fun!"
+    result = ciphertext text
+    expected = Ok "tsf hiu isn"
+    result == expected
+
+# 8 character plaintext results in 3 chunks, the last one with a trailing space
+expect
+    text = "Chill out."
+    result = ciphertext text
+    expected = Ok "clu hlt io "
+    result == expected
+
+# 54 character plaintext results in 7 chunks, the last two with trailing spaces
+expect
+    text = "If man was meant to stay on the ground, god would have given us roots."
+    result = ciphertext text
+    expected = Ok "imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau "
+    result == expected
+