feat: Add Pop Count (#72)

config.json

@@ -174,6 +174,13 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 2
+      }, {
+        "slug": "pop-count",
+        "name": "Pop Count",
+        "uuid": "233fde6a-79d9-4d90-8f94-2a0519352a5c",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
       }, {
         "slug": "pangram",
         "name": "Pangram",

exercises/practice/pop-count/.docs/instructions.append.md

@@ -0,0 +1,3 @@
+## Reserved Addresses
+
+No linear memory is required for this exercise.

exercises/practice/pop-count/.docs/instructions.md

@@ -0,0 +1,8 @@
+# Instructions
+
+Your task is to count the number of 1 bits in the binary representation of a number.
+
+## Restrictions
+
+Keep your hands off that bit-count functionality provided by your standard library!
+Solve this one yourself using other basic tools instead.

exercises/practice/pop-count/.docs/introduction.md

@@ -0,0 +1,47 @@
+# Introduction
+
+Your friend Eliud inherited a farm from her grandma Tigist.
+Her granny was an inventor and had a tendency to build things in an overly complicated manner.
+The chicken coop has a digital display showing an encoded number representing the positions of all eggs that could be picked up.
+
+Eliud is asking you to write a program that shows the actual number of eggs in the coop.
+
+The position information encoding is calculated as follows:
+
+1. Scan the potential egg-laying spots and mark down a `1` for an existing egg or a `0` for an empty spot.
+2. Convert the number from binary to decimal.
+3. Show the result on the display.
+
+Example 1:
+
+```text
+Chicken Coop:
+ _ _ _ _ _ _ _
+|E| |E|E| | |E|
+
+Resulting Binary:
+ 1 0 1 1 0 0 1
+
+Decimal number on the display:
+89
+
+Actual eggs in the coop:
+4
+```
+
+Example 2:
+
+```text
+Chicken Coop:
+ _ _ _ _ _ _ _ _
+| | | |E| | | | |
+
+Resulting Binary:
+ 0 0 0 1 0 0 0 0
+
+Decimal number on the display:
+16
+
+Actual eggs in the coop:
+1
+```

exercises/practice/pop-count/.eslintrc

@@ -0,0 +1,18 @@
+{
+  "root": true,
+  "extends": "@exercism/eslint-config-javascript",
+  "env": {
+    "jest": true
+  },
+  "overrides": [
+    {
+      "files": [
+        "*.spec.js"
+      ],
+      "excludedFiles": [
+        "custom.spec.js"
+      ],
+      "extends": "@exercism/eslint-config-javascript/maintainers"
+    }
+  ]
+}

exercises/practice/pop-count/.meta/config.json

@@ -0,0 +1,25 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "pop-count.wat"
+    ],
+    "test": [
+      "pop-count.spec.js"
+    ],
+    "example": [
+      ".meta/proof.ci.wat"
+    ]
+  },
+  "blurb": "Count the 1 bits in a number",
+  "source": "Christian Willner, Eric Willigers",
+  "source_url": "https://forum.exercism.org/t/new-exercise-suggestion-pop-count/7632/5",
+  "custom": {
+    "version.tests.compatibility": "jest-27",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false
+  }
+}

exercises/practice/pop-count/.meta/proof.ci.wat

@@ -0,0 +1,24 @@
+(module
+  (func (export "eggCount") (param $number i32) (result i32)
+    (local $remaining i32)
+    (local $count i32)
+
+    (if (i32.eq (local.get $number) (i32.const 0))(then
+      (return (i32.const 0))
+    ))
+
+    (local.set $remaining (local.get $number))
+    (local.set $count (i32.const 0))
+
+    ;; do while $remaining != 0
+    (loop
+      ;; Clear least-significant 1 bit using
+      ;; $remaining -= $remaining & -$remaining
+      (local.set $remaining (i32.sub (local.get $remaining) (i32.and (local.get $remaining) (i32.sub (i32.const 0) (local.get $remaining)))))
+      (local.set $count (i32.add (local.get $count) (i32.const 1)))
+      (br_if 0 (i32.ne (local.get $remaining) (i32.const 0)))
+    )
+
+    (return (local.get $count))
+  )
+)

exercises/practice/pop-count/.meta/tests.toml

@@ -0,0 +1,15 @@
+# This is an auto-generated file. Regular comments will be removed when this
+# file is regenerated. Regenerating will not touch any manually added keys,
+# so comments can be added in a "comment" key.
+
+[559e789d-07d1-4422-9004-3b699f83bca3]
+description = "0 eggs"
+
+[97223282-f71e-490c-92f0-b3ec9e275aba]
+description = "1 egg"
+
+[1f8fd18f-26e9-4144-9a0e-57cdfc4f4ff5]
+description = "4 eggs"
+
+[0c18be92-a498-4ef2-bcbb-28ac4b06cb81]
+description = "13 eggs"

exercises/practice/pop-count/.npmrc

@@ -0,0 +1 @@
+audit=false

exercises/practice/pop-count/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 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/pop-count/babel.config.js

@@ -0,0 +1,4 @@
+export default {
+  presets: ["@exercism/babel-preset-javascript"],
+  plugins: [],
+};

exercises/practice/pop-count/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "@exercism/wasm-pop-count",
+  "description": "Exercism exercises in WebAssembly.",
+  "type": "module",
+  "private": true,
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/wasm",
+    "directory": "exercises/practice/pop-count"
+  },
+  "jest": {
+    "maxWorkers": 1
+  },
+  "devDependencies": {
+    "@babel/core": "^7.20.12",
+    "@exercism/babel-preset-javascript": "^0.2.1",
+    "@exercism/eslint-config-javascript": "^0.6.0",
+    "@types/jest": "^29.4.0",
+    "@types/node": "^18.13.0",
+    "babel-jest": "^29.4.2",
+    "core-js": "^3.27.2",
+    "eslint": "^8.34.0",
+    "jest": "^29.4.2"
+  },
+  "dependencies": {
+    "@exercism/wasm-lib": "^0.1.0"
+  },
+  "scripts": {
+    "test": "node --experimental-vm-modules node_modules/jest/bin/jest.js ./*",
+    "watch": "node --experimental-vm-modules node_modules/jest/bin/jest.js --watch ./*",
+    "lint": "eslint ."
+  }
+}

exercises/practice/pop-count/pop-count.spec.js

@@ -0,0 +1,48 @@
+import { compileWat, WasmRunner } from "@exercism/wasm-lib";
+
+let wasmModule;
+let currentInstance;
+
+beforeAll(async () => {
+  try {
+    const watPath = new URL("./pop-count.wat", import.meta.url);
+    const { buffer } = await compileWat(watPath);
+    wasmModule = await WebAssembly.compile(buffer);
+  } catch (err) {
+    console.log(`Error compiling *.wat: ${err}`);
+    process.exit(1);
+  }
+});
+
+describe("eggCount()", () => {
+  beforeEach(async () => {
+    currentInstance = null;
+
+    if (!wasmModule) {
+      return Promise.reject();
+    }
+    try {
+      currentInstance = await new WasmRunner(wasmModule);
+      return Promise.resolve();
+    } catch (err) {
+      console.log(`Error instantiating WebAssembly module: ${err}`);
+      return Promise.reject();
+    }
+  });
+
+  test("0 eggs", () => {
+    expect(currentInstance.exports.eggCount(0)).toEqual(0);
+  });
+
+  xtest("1 egg", () => {
+    expect(currentInstance.exports.eggCount(16)).toEqual(1);
+  });
+
+  xtest("4 eggs", () => {
+    expect(currentInstance.exports.eggCount(89)).toEqual(4);
+  });
+
+  xtest("13 eggs", () => {
+    expect(currentInstance.exports.eggCount(2000000000)).toEqual(13);
+  });
+});

exercises/practice/pop-count/pop-count.wat

@@ -0,0 +1,24 @@
+(module
+  (func (export "eggCount") (param $number i32) (result i32)
+    (local $remaining i32)
+    (local $count i32)
+
+    (if (i32.eq (local.get $number) (i32.const 0))(then
+      (return (i32.const 0))
+    ))
+
+    (local.set $remaining (i32.const 0))
+    (local.set $count (i32.const 0))
+
+    ;; do while $remaining != 0
+    (loop
+      ;; Clear least-significant 1 bit using
+      ;; $remaining -= $remaining & -$remaining
+      (local.set $remaining (i32.sub (local.get $remaining) (i32.and (local.get $remaining) (i32.sub (i32.const 0) (local.get $remaining)))))
+      (local.set $count (i32.add (local.get $count) (i32.const 1)))
+      (br_if 0 (i32.ne (local.get $remaining) (i32.const 0)))
+    )
+
+    (return (local.get $count))
+  )
+)