php/accumulate

php/accumulate/.exercism/config.json

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+{
+  "blurb": "Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.",
+  "authors": ["pmatseykanets"],
+  "contributors": ["arueckauer", "kunicmarko20", "kytrinyx", "petemcfarlane"],
+  "files": {
+    "solution": ["Accumulate.php"],
+    "test": ["AccumulateTest.php"],
+    "example": [".meta/example.php"]
+  },
+  "source": "Conversation with James Edward Gray II",
+  "source_url": "https://twitter.com/jeg2"
+}

php/accumulate/.exercism/metadata.json

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+{"track":"php","exercise":"accumulate","id":"eaba0161e1314aeabdfd452f0293d217","url":"https://exercism.org/tracks/php/exercises/accumulate","handle":"benharri","is_requester":true,"auto_approve":false}

php/accumulate/Accumulate.php

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+<?php
+
+declare(strict_types=1);
+
+function accumulate(array $input, callable $accumulator): array
+{
+    $result = [];
+    foreach ($input as $i)
+        $result[] = $accumulator($i);
+    return $result;
+}

php/accumulate/AccumulateTest.php

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+<?php
+
+/*
+ * By adding type hints and enabling strict type checking, code can become
+ * easier to read, self-documenting and reduce the number of potential bugs.
+ * By default, type declarations are non-strict, which means they will attempt
+ * to change the original type to match the type specified by the
+ * type-declaration.
+ *
+ * In other words, if you pass a string to a function requiring a float,
+ * it will attempt to convert the string value to a float.
+ *
+ * To enable strict mode, a single declare directive must be placed at the top
+ * of the file.
+ * This means that the strictness of typing is configured on a per-file basis.
+ * This directive not only affects the type declarations of parameters, but also
+ * a function's return type.
+ *
+ * For more info review the Concept on strict type checking in the PHP track
+ * <link>.
+ *
+ * To disable strict typing, comment out the directive below.
+ */
+
+declare(strict_types=1);
+
+class AccumulateTest extends PHPUnit\Framework\TestCase
+{
+    public static function setUpBeforeClass(): void
+    {
+        require_once 'Accumulate.php';
+    }
+
+    public function testAccumulateEmpty(): void
+    {
+        $accumulator = function ($value) {
+            return $value ** 2;
+        };
+
+        $this->assertEquals([], accumulate([], $accumulator));
+    }
+
+    public function testAccumulateSquares(): void
+    {
+        $accumulator = function ($value) {
+            return $value ** 2;
+        };
+
+        $this->assertEquals([1, 4, 9], accumulate([1, 2, 3], $accumulator));
+    }
+
+    public function testAccumulateUpperCases(): void
+    {
+        $accumulator = function ($string) {
+            return mb_strtoupper($string);
+        };
+
+        $this->assertEquals(['HELLO', 'WORLD!'], accumulate(['Hello', 'World!'], $accumulator));
+    }
+
+    public function testAccumulateReversedStrings(): void
+    {
+        $accumulator = function ($string) {
+            return strrev($string);
+        };
+
+        $this->assertEquals(['Hello', 'World!'], accumulate(['olleH', '!dlroW'], $accumulator));
+    }
+
+    public function testAccumulateConstants(): void
+    {
+        $accumulator = function () {
+            return 1;
+        };
+
+        $this->assertEquals([1, 1], accumulate(['Hello', 'World!'], $accumulator));
+    }
+
+    public function testAccumulateWithinAccumulate(): void
+    {
+        $chars = ['a', 'b', 'c'];
+        $digits = [1, 2, 3];
+        $expected = [['a1', 'a2', 'a3'], ['b1', 'b2', 'b3'], ['c1', 'c2', 'c3']];
+
+        $this->assertEquals(
+            $expected,
+            accumulate($chars, function ($char) use ($digits) {
+                return accumulate($digits, function ($digit) use ($char) {
+                    return $char . $digit;
+                });
+            })
+        );
+    }
+
+    // Additional points for making the following tests pass
+
+    public function testAccumulateUsingBuiltInFunction(): void
+    {
+        $this->assertEquals(['Hello', 'World!'], accumulate([" Hello\t", "\t World!\n "], 'trim'));
+    }
+
+    public function testAccumulateUsingStaticMethod(): void
+    {
+        $this->assertEquals([5, 6], accumulate(['Hello', 'World!'], 'Str::len'));
+    }
+
+    public function testAccumulateUsingInvoke(): void
+    {
+        $this->assertEquals([['f', 'o', 'o']], accumulate(['foo'], new StrSpliter()));
+    }
+
+    public function testAccumulateUsingObjectAndArrayNotation(): void
+    {
+        $this->assertEquals([true, false, false], accumulate(['Yes', 0, []], [new Is(), 'truthy']));
+    }
+}
+
+class Str
+{
+    public static function len($string): int
+    {
+        return strlen($string);
+    }
+}
+
+class StrSpliter
+{
+    public function __invoke($value)
+    {
+        return str_split($value);
+    }
+}
+
+class Is
+{
+    public function truthy($value): bool
+    {
+        return boolval($value);
+    }
+}

php/accumulate/HELP.md

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+# Help
+
+## Running the tests
+
+## Running the tests
+
+1. Go to the root of your PHP exercise directory, which is `<EXERCISM_WORKSPACE>/php`.
+   To find the Exercism workspace run
+
+       ➜ exercism debug | grep Workspace
+
+1. Get [PHPUnit] if you don't have it already.
+
+       ➜ wget -O phpunit https://phar.phpunit.de/phpunit-9.phar
+       ➜ chmod +x phpunit
+       ➜ ./phpunit --version
+
+2. Execute the tests:
+
+       ➜ ./phpunit file_to_test.php
+
+   For example, to run the tests for the Hello World exercise, you would run:
+
+       ➜ ./phpunit HelloWorldTest.php
+
+[PHPUnit]: http://phpunit.de
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit Accumulate.php` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [PHP track's documentation](https://exercism.org/docs/tracks/php)
+- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+To get help if you're having trouble, you can use one of the following resources:
+
+ - [/r/php](https://www.reddit.com/r/php) is the PHP subreddit.
+ - [StackOverflow](https://stackoverflow.com/questions/tagged/php) can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.

php/accumulate/README.md

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+# Accumulate
+
+Welcome to Accumulate on Exercism's PHP Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Implement the `accumulate` operation, which, given a collection and an
+operation to perform on each element of the collection, returns a new
+collection containing the result of applying that operation to each element of
+the input collection.
+
+Given the collection of numbers:
+
+- 1, 2, 3, 4, 5
+
+And the operation:
+
+- square a number (`x => x * x`)
+
+Your code should be able to produce the collection of squares:
+
+- 1, 4, 9, 16, 25
+
+Check out the test suite to see the expected function signature.
+
+## Restrictions
+
+Keep your hands off that collect/map/fmap/whatchamacallit functionality
+provided by your standard library!
+Solve this one yourself using other basic tools instead.
+
+## Source
+
+### Created by
+
+- @pmatseykanets
+
+### Contributed to by
+
+- @arueckauer
+- @kunicmarko20
+- @kytrinyx
+- @petemcfarlane
+
+### Based on
+
+Conversation with James Edward Gray II - https://twitter.com/jeg2