--- /dev/null
+<?php
+
+/*
+ * This file is part of Psy Shell.
+ *
+ * (c) 2012-2017 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Psy\CodeCleaner;
+
+use PhpParser\Node\Scalar\LNumber;
+use PhpParser\Node\Stmt\Declare_ as DeclareStmt;
+use PhpParser\Node\Stmt\DeclareDeclare;
+use Psy\Exception\FatalErrorException;
+
+/**
+ * Provide implicit strict types declarations for for subsequent execution.
+ *
+ * The strict types pass remembers the last strict types declaration:
+ *
+ * declare(strict_types=1);
+ *
+ * ... which it then applies implicitly to all future evaluated code, until it
+ * is replaced by a new declaration.
+ */
+class StrictTypesPass extends CodeCleanerPass
+{
+ private $strictTypes = false;
+
+ /**
+ * If this is a standalone strict types declaration, remember it for later.
+ *
+ * Otherwise, apply remembered strict types declaration to to the code until
+ * a new declaration is encountered.
+ *
+ * @throws FatalErrorException if an invalid `strict_types` declaration is found
+ *
+ * @param array $nodes
+ */
+ public function beforeTraverse(array $nodes)
+ {
+ if (version_compare(PHP_VERSION, '7.0', '<')) {
+ return;
+ }
+
+ $prependStrictTypes = $this->strictTypes;
+
+ foreach ($nodes as $key => $node) {
+ if ($node instanceof DeclareStmt) {
+ foreach ($node->declares as $declare) {
+ if ($declare->key === 'strict_types') {
+ $value = $declare->value;
+ if (!$value instanceof LNumber || ($value->value !== 0 && $value->value !== 1)) {
+ throw new FatalErrorException('strict_types declaration must have 0 or 1 as its value');
+ }
+
+ $this->strictTypes = $value->value === 1;
+ }
+ }
+ }
+ }
+
+ if ($prependStrictTypes) {
+ $first = reset($nodes);
+ if (!$first instanceof DeclareStmt) {
+ $declare = new DeclareStmt(array(new DeclareDeclare('strict_types', new LNumber(1))));
+ array_unshift($nodes, $declare);
+ }
+ }
+
+ return $nodes;
+ }
+}