Add sieve exercise (#93)

config.json

@@ -287,6 +287,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "sieve",
+        "name": "Sieve",
+        "uuid": "47e2f7c0-94f7-49a1-b423-32c7e77d0a97",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "square-root",
         "name": "Square Root",

exercises/practice/sieve/.docs/instructions.md

@@ -0,0 +1,42 @@
+# Instructions
+
+Your task is to create a program that implements the Sieve of Eratosthenes algorithm to find all prime numbers less than or equal to a given number.
+
+A prime number is a number larger than 1 that is only divisible by 1 and itself.
+For example, 2, 3, 5, 7, 11, and 13 are prime numbers.
+By contrast, 6 is _not_ a prime number as it not only divisible by 1 and itself, but also by 2 and 3.
+
+To use the Sieve of Eratosthenes, you first create a list of all the numbers between 2 and your given number.
+Then you repeat the following steps:
+
+1. Find the next unmarked number in your list (skipping over marked numbers).
+   This is a prime number.
+2. Mark all the multiples of that prime number as **not** prime.
+
+You keep repeating these steps until you've gone through every number in your list.
+At the end, all the unmarked numbers are prime.
+
+~~~~exercism/note
+The tests don't check that you've implemented the algorithm, only that you've come up with the correct list of primes.
+To check you are implementing the Sieve correctly, a good first test is to check that you do not use division or remainder operations.
+~~~~
+
+## Example
+
+Let's say you're finding the primes less than or equal to 10.
+
+- List out 2, 3, 4, 5, 6, 7, 8, 9, 10, leaving them all unmarked.
+- 2 is unmarked and is therefore a prime.
+  Mark 4, 6, 8 and 10 as "not prime".
+- 3 is unmarked and is therefore a prime.
+  Mark 6 and 9 as not prime _(marking 6 is optional - as it's already been marked)_.
+- 4 is marked as "not prime", so we skip over it.
+- 5 is unmarked and is therefore a prime.
+  Mark 10 as not prime _(optional - as it's already been marked)_.
+- 6 is marked as "not prime", so we skip over it.
+- 7 is unmarked and is therefore a prime.
+- 8 is marked as "not prime", so we skip over it.
+- 9 is marked as "not prime", so we skip over it.
+- 10 is marked as "not prime", so we stop as there are no more numbers to check.
+
+You've examined all numbers and found 2, 3, 5, and 7 are still unmarked, which means they're the primes less than or equal to 10.

exercises/practice/sieve/.docs/introduction.md

@@ -0,0 +1,7 @@
+# Introduction
+
+You bought a big box of random computer parts at a garage sale.
+You've started putting the parts together to build custom computers.
+
+You want to test the performance of different combinations of parts, and decide to create your own benchmarking program to see how your computers compare.
+You choose the famous "Sieve of Eratosthenes" algorithm, an ancient algorithm, but one that should push your computers to the limits.

exercises/practice/sieve/.meta/Example.roc

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+module [primes]
+
+primes : U64 -> List U64
+primes = \limit ->
+    if limit < 2 then
+        []
+        else
+
+    help = \candidates, foundPrimes ->
+        when candidates is
+            [] -> foundPrimes
+            [0, .. as rest] -> rest |> help foundPrimes
+            [prime, .. as rest] ->
+                List.range { start: After prime, end: At limit, step: prime }
+                |> List.walk rest \filteredCandidates, multipleOfPrime ->
+                    filteredCandidates |> List.replace (multipleOfPrime - prime - 1) 0 |> .list
+                |> help (foundPrimes |> List.append prime)
+    help (List.range { start: At 2, end: At limit }) []

exercises/practice/sieve/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "ageron"
+  ],
+  "files": {
+    "solution": [
+      "Sieve.roc"
+    ],
+    "test": [
+      "sieve-test.roc"
+    ],
+    "example": [
+      ".meta/Example.roc"
+    ]
+  },
+  "blurb": "Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.",
+  "source": "Sieve of Eratosthenes at Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes"
+}

exercises/practice/sieve/.meta/template.j2

@@ -0,0 +1,13 @@
+{%- 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
+    result = {{ case["property"] | to_camel }} {{ case["input"]["limit"] | to_roc }}
+    result == {{ case["expected"] | to_roc }}
+
+{% endfor %}

exercises/practice/sieve/.meta/tests.toml

@@ -0,0 +1,25 @@
+# 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.
+
+[88529125-c4ce-43cc-bb36-1eb4ddd7b44f]
+description = "no primes under two"
+
+[4afe9474-c705-4477-9923-840e1024cc2b]
+description = "find first prime"
+
+[974945d8-8cd9-4f00-9463-7d813c7f17b7]
+description = "find primes up to 10"
+
+[2e2417b7-3f3a-452a-8594-b9af08af6d82]
+description = "limit is prime"
+
+[92102a05-4c7c-47de-9ed0-b7d5fcd00f21]
+description = "find primes up to 1000"

exercises/practice/sieve/Sieve.roc

@@ -0,0 +1,5 @@
+module [primes]
+
+primes : U64 -> List U64
+primes = \limit ->
+    crash "Please implement the 'primes' function"

exercises/practice/sieve/sieve-test.roc

@@ -0,0 +1,37 @@
+# These tests are auto-generated with test data from:
+# https://github.com/exercism/problem-specifications/tree/main/exercises/sieve/canonical-data.json
+# File last updated on 2024-09-15
+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 Sieve exposing [primes]
+
+# no primes under two
+expect
+    result = primes 1
+    result == []
+
+# find first prime
+expect
+    result = primes 2
+    result == [2]
+
+# find primes up to 10
+expect
+    result = primes 10
+    result == [2, 3, 5, 7]
+
+# limit is prime
+expect
+    result = primes 13
+    result == [2, 3, 5, 7, 11, 13]
+
+# find primes up to 1000
+expect
+    result = primes 1000
+    result == [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997]
+