Add support for IFS() logical function (#1442)

* Add support for IFS() logical function

* Use Exception as false value in IFS logical function, so it never collides with string in spreadsheet

docs/references/function-list-by-category.md

@@ -213,7 +213,7 @@ FALSE               | \PhpOffice\PhpSpreadsheet\Calculation\Logical::FALSE
 IF                  | \PhpOffice\PhpSpreadsheet\Calculation\Logical::statementIf
 IFERROR             | \PhpOffice\PhpSpreadsheet\Calculation\Logical::IFERROR
 IFNA                | \PhpOffice\PhpSpreadsheet\Calculation\Logical::IFNA
-IFS                 | **Not yet Implemented**
+IFS                 | \PhpOffice\PhpSpreadsheet\Calculation\Logical::IFS
 NOT                 | \PhpOffice\PhpSpreadsheet\Calculation\Logical::NOT
 OR                  | \PhpOffice\PhpSpreadsheet\Calculation\Logical::logicalOr
 SWITCH              | \PhpOffice\PhpSpreadsheet\Calculation\Logical::statementSwitch

docs/references/function-list-by-name.md

@@ -212,7 +212,7 @@ Excel Function      | Category                       | PhpSpreadsheet Function
 IF                  | CATEGORY_LOGICAL               | \PhpOffice\PhpSpreadsheet\Calculation\Logical::statementIf
 IFERROR             | CATEGORY_LOGICAL               | \PhpOffice\PhpSpreadsheet\Calculation\Logical::IFERROR
 IFNA                | CATEGORY_LOGICAL               | \PhpOffice\PhpSpreadsheet\Calculation\Logical::IFNA
-IFS                 | CATEGORY_LOGICAL               | **Not yet Implemented**
+IFS                 | CATEGORY_LOGICAL               | \PhpOffice\PhpSpreadsheet\Calculation\Logical::IFS
 IMABS               | CATEGORY_ENGINEERING           | \PhpOffice\PhpSpreadsheet\Calculation\Engineering::IMABS
 IMAGINARY           | CATEGORY_ENGINEERING           | \PhpOffice\PhpSpreadsheet\Calculation\Engineering::IMAGINARY
 IMARGUMENT          | CATEGORY_ENGINEERING           | \PhpOffice\PhpSpreadsheet\Calculation\Engineering::IMARGUMENT

src/PhpSpreadsheet/Calculation/Calculation.php

@@ -1059,7 +1059,7 @@ class Calculation
         ],
         'IFS' => [
             'category' => Category::CATEGORY_LOGICAL,
-            'functionCall' => [Functions::class, 'DUMMY'],
+            'functionCall' => [Logical::class, 'IFS'],
             'argumentCount' => '2+',
         ],
         'IMABS' => [

src/PhpSpreadsheet/Calculation/Logical.php

@@ -352,4 +352,39 @@ class Logical
 
         return self::statementIf(Functions::isNa($testValue), $napart, $testValue);
     }
+
+    /**
+     * IFS.
+     *
+     * Excel Function:
+     *         =IFS(testValue1;returnIfTrue1;testValue2;returnIfTrue2;...;testValue_n;returnIfTrue_n)
+     *
+     *         testValue1 ... testValue_n
+     *             Conditions to Evaluate
+     *         returnIfTrue1 ... returnIfTrue_n
+     *             Value returned if corresponding testValue (nth) was true
+     *
+     * @param mixed ...$arguments Statement arguments
+     *
+     * @return mixed|string The value of returnIfTrue_n, if testValue_n was true. #N/A if none of testValues was true
+     */
+    public static function IFS(...$arguments)
+    {
+        if (count($arguments) % 2 != 0) {
+            return Functions::NA();
+        }
+        // We use instance of Exception as a falseValue in order to prevent string collision with value in cell
+        $falseValueException = new Exception();
+        for ($i = 0; $i < count($arguments); $i += 2) {
+            $testValue = ($arguments[$i] === null) ? '' : Functions::flattenSingleValue($arguments[$i]);
+            $returnIfTrue = ($arguments[$i + 1] === null) ? '' : Functions::flattenSingleValue($arguments[$i + 1]);
+            $result = self::statementIf($testValue, $returnIfTrue, $falseValueException);
+
+            if ($result !== $falseValueException) {
+                return $result;
+            }
+        }
+
+        return Functions::NA();
+    }
 }

src/PhpSpreadsheet/Calculation/functionlist.txt

@@ -163,6 +163,7 @@ HYPERLINK
 HYPGEOMDIST
 IF
 IFERROR
+IFS
 IMABS
 IMAGINARY
 IMARGUMENT

tests/PhpSpreadsheetTests/Calculation/Functions/Logical/IfsTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Logical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Logical;
+use PHPUnit\Framework\TestCase;
+
+class IfsTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerIFS
+     *
+     * @param mixed $expectedResult
+     * @param mixed $args
+     */
+    public function testIFS($expectedResult, ...$args): void
+    {
+        $result = Logical::IFS(...$args);
+        self::assertEquals($expectedResult, $result);
+    }
+
+    public function providerIFS()
+    {
+        return require 'tests/data/Calculation/Logical/IFS.php';
+    }
+}

tests/data/Calculation/Logical/IFS.php

@@ -0,0 +1,50 @@
+<?php
+
+return [
+    [
+        '#N/A',
+    ],
+    [
+        1,
+        true,
+        1,
+    ],
+    [
+        '#N/A',
+        false,
+        1,
+        true,
+    ],
+    [
+        'ABC',
+        true,
+        'ABC',
+    ],
+    [
+        '#N/A',
+        false,
+        false,
+        false,
+        1,
+        false,
+        'ABC',
+    ],
+    [
+        'ABC',
+        false,
+        false,
+        false,
+        1,
+        true,
+        'ABC',
+    ],
+    [
+        false,
+        true,
+        false,
+        false,
+        1,
+        true,
+        'ABC',
+    ],
+];