formula while

application/Espo/Core/Formula/Functions/Base.php

@@ -122,4 +122,9 @@ abstract class Base implements Injectable
 
         return $eArgs;
     }
-}
+
+    protected function fetchRawArguments(\StdClass $item)
+    {
+        return $item->value ?? [];
+    }
+}

application/Espo/Core/Formula/Functions/WhileType.php

@@ -0,0 +1,48 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM - Open Source CRM application.
+ * Copyright (C) 2014-2020 Yuri Kuznetsov, Taras Machyshyn, Oleksiy Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * EspoCRM is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * EspoCRM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace Espo\Core\Formula\Functions;
+
+use Espo\Core\Exceptions\Error;
+
+class WhileType extends Base
+{
+    public function process(\StdClass $item)
+    {
+        $args = $this->fetchRawArguments($item);
+
+        if (count($args) < 2) {
+            throw new Error("Function \'while\' should receieve 2 arguments.");
+        }
+
+        while ($this->evaluate($args[0])) {
+            $this->evaluate($args[1]);
+        }
+    }
+}

tests/unit/Espo/Core/Formula/EvaluatorTest.php

@@ -165,4 +165,27 @@ class EvaluatorTest extends \PHPUnit\Framework\TestCase
         $actual = $this->evaluator->process($expression);
         $this->assertEquals(4, $actual);
     }
+
+    public function testWhile()
+    {
+        $expression = "
+            \$source = list(0, 1, 2);
+            \$target = list();
+
+            \$i = 0;
+            while(\$i < array\\length(\$source),
+                \$target = array\\push(
+                    \$target,
+                    array\\at(\$source, \$i)
+                );
+                \$i = \$i + 1;
+            );
+        ";
+
+        $vars = (object) [];
+
+        $this->evaluator->process($expression, null, $vars);
+
+        $this->assertEquals([0, 1, 2], $vars->target);
+    }
 }