From 8d1795d4a1a11841f192f4d5bd7465bf2c79c553 Mon Sep 17 00:00:00 2001
From: David Grudl <david@grudl.com>
Date: Wed, 13 Sep 2023 16:00:34 +0200
Subject: [PATCH] added function blockExists() [Closes #345]

---
 src/Latte/Essential/CoreExtension.php |  9 +++++++++
 tests/tags/block.blockExists.phpt     | 23 +++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 tests/tags/block.blockExists.phpt

diff --git a/src/Latte/Essential/CoreExtension.php b/src/Latte/Essential/CoreExtension.php
index 09a490620..3c45fb447 100644
--- a/src/Latte/Essential/CoreExtension.php
+++ b/src/Latte/Essential/CoreExtension.php
@@ -15,6 +15,7 @@
 use Latte\Compiler\Nodes\TextNode;
 use Latte\Compiler\Tag;
 use Latte\Compiler\TemplateParser;
+use Latte\Runtime;
 use Latte\RuntimeException;
 use Nette;
 
@@ -28,6 +29,7 @@ final class CoreExtension extends Latte\Extension
 
 	private array $functions;
 	private bool $strict;
+	private Runtime\Template $template;
 
 
 	public function beforeCompile(Latte\Engine $engine): void
@@ -37,6 +39,12 @@ public function beforeCompile(Latte\Engine $engine): void
 	}
 
 
+	public function beforeRender(Runtime\Template $template): void
+	{
+		$this->template = $template;
+	}
+
+
 	public function getTags(): array
 	{
 		return [
@@ -180,6 +188,7 @@ public function getFunctions(): array
 			'last' => [Filters::class, 'last'],
 			'odd' => [Filters::class, 'odd'],
 			'slice' => [Filters::class, 'slice'],
+			'blockExists' => fn(string $name): bool => $this->template->hasBlock($name),
 		];
 	}
 
diff --git a/tests/tags/block.blockExists.phpt b/tests/tags/block.blockExists.phpt
new file mode 100644
index 000000000..1c2e40086
--- /dev/null
+++ b/tests/tags/block.blockExists.phpt
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+$latte = new Latte\Engine;
+$latte->setLoader(new Latte\Loaders\StringLoader);
+
+Assert::match(
+	<<<'EOD'
+		Main: true
+		Foo: false
+		EOD,
+	$latte->renderToString(<<<'EOD'
+		{block main}{/block}
+		Main: {=var_export(blockExists(main), true)}
+		Foo: {=var_export(blockExists(foo), true)}
+		EOD),
+);