Merge pull request #46 from jorgeavilacardenosa/do-if-function

do_if function

docs/docs.md

@@ -10,6 +10,7 @@
  * [complement](functions/complement.md): Returns another function that takes the same arguments and has the opposite truth value.
  * [compose](functions/compose.md): Combine multiple function calls in one function
  * [dissoc](functions/dissoc.md): Dissociate a value of a key in a collection
+ * [do_if](functions/do_if.md): Returns a callable that will call the given function if the result of applying the callable arguments to the predicates is true for all of them
  * [each](functions/each.md): Apply a function over all the items of a collection
  * [filter](functions/filter.md): Discriminate the items of a collection for which function is false
  * [first](functions/first.md): Returns the first element of a collection

docs/functions/do_if.md

@@ -0,0 +1,27 @@
+# do_if
+
+## Description
+Returns a function that will call the given function if the result of applying the callable arguments to the predicates is true for all of them
+If the result of applying the callable arguments to the predicates is false for any of them, the given function will not be executed (returning null).
+
+## Parameters
+
+<dl>
+  <dt>fn</dt>
+  <dd>Function to call if all predicates are valid.</dd>
+
+  <dt>predicates</dt>
+  <dd>Predicates to be validated.</dd>
+</dl>
+
+## Examples
+
+```php
+<?php
+
+use function Akamon\Phunctional\do_if;
+use function Akamon\Phunctional\apply;
+
+apply(do_if($this->sendBirthdayGift(), [$this->isBirthday(), $this->isAdult()]), [$user]);
+
+```

src/_bootstrap.php

@@ -8,6 +8,7 @@
 require __DIR__ . '/complement.php';
 require __DIR__ . '/compose.php';
 require __DIR__ . '/dissoc.php';
+require __DIR__ . '/do_if.php';
 require __DIR__ . '/each.php';
 require __DIR__ . '/filter.php';
 require __DIR__ . '/first.php';

src/do_if.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Akamon\Phunctional;
+
+/**
+ * Returns a callable that will call the given function if the result of applying
+ * the callable arguments to the predicates is true for all of them.
+ *
+ * @since 0.1
+ *
+ * @param callable   $fn         Function to call if all predicates are valid.
+ * @param callable[] $predicates Predicates to validate.
+ *
+ * @return callable|null
+ */
+function do_if(callable $fn, array $predicates)
+{
+    return function (...$args) use ($fn, $predicates) {
+        $isValid = function ($predicate) use ($args) {
+            return $predicate(...$args);
+        };
+
+        return all($isValid, $predicates) ? $fn(...$args) : null;
+    };
+}

tests/DoIfTest.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Akamon\Phunctional\Tests;
+
+use function Akamon\Phunctional\apply;
+use function Akamon\Phunctional\do_if;
+use PHPUnit_Framework_TestCase;
+
+final class DoIfTest extends PHPUnit_Framework_TestCase
+{
+    /** @test */
+    public function it_should_call_the_fn_if_predicates_are_true()
+    {
+        $this->assertEquals(5, apply(do_if($this->sumOne(), [$this->isOdd()]), [4]));
+    }
+
+    /** @test */
+    public function it_should_return_null_if_all_predicates_are_not_true()
+    {
+        $this->assertNull(apply(do_if($this->sumOne(), [$this->isGreaterThanOne(), $this->isOdd()]), [3]));
+    }
+
+    private function sumOne()
+    {
+        return function ($num) {
+            return $num + 1;
+        };
+    }
+
+    private function isOdd()
+    {
+        return function ($num) {
+            return $num % 2 === 0;
+        };
+    }
+
+    private function isGreaterThanOne()
+    {
+        return function ($num) {
+            return $num > 1;
+        };
+    }
+}