twiggy: compiles html_classes as n:class

src/TwigConverter.php

@@ -30,6 +30,14 @@ public function convert(string $code): string
 		$loader = $this->twiggy->getLoader();
 		$loader->setTemplate('main', $code);
 		$code = $this->twiggy->compileSource($loader->getSourceContext('main'));
+		$code = $this->postProcess($code);
+		return $code;
+	}
+
+
+	private function postProcess(string $code): string
+	{
+		$code = preg_replace('~\bclass=(["\']){html_classes\((.*)\)}~i', 'n:class=$1$2', $code);
 		return $code;
 	}
 }

src/Twiggy/Node/Node.php

@@ -154,6 +154,12 @@ public function setNode(int|string $name, self $node): void
 	}
 
 
+	public function setNodes(array $nodes): void
+	{
+		$this->nodes = $nodes;
+	}
+
+
 	public function removeNode(int|string $name): void
 	{
 		unset($this->nodes[$name]);

src/Twiggy/NodeVisitor/LatteNodeVisitor.php

@@ -13,6 +13,9 @@
 namespace LatteTools\Twiggy\NodeVisitor;
 
 use LatteTools\Twiggy\Environment;
+use LatteTools\Twiggy\Node\Expression\ArrayExpression;
+use LatteTools\Twiggy\Node\Expression\ConditionalExpression;
+use LatteTools\Twiggy\Node\Expression\ConstantExpression;
 use LatteTools\Twiggy\Node\Expression\FilterExpression;
 use LatteTools\Twiggy\Node\Expression\FunctionExpression;
 use LatteTools\Twiggy\Node\Expression\MethodCallExpression;
@@ -41,6 +44,15 @@ public function leaveNode(Node $node, Environment $env): ?Node
 			return $this->filterToFunction($node);
 		}
 
+		if ($node instanceof FunctionExpression) {
+			$name = $node->getAttribute('name');
+
+			// html_classes
+			if ($name === 'html_classes') {
+				return $this->functionHtmlClasses($node);
+			}
+		}
+
 		if ($node instanceof PrintNode) {
 			$expr = $node->getNode('expr');
 
@@ -88,4 +100,27 @@ private function filterToFunction(FilterExpression $node): Node
 		}
 		return new FunctionExpression($funcs[$name], new Node($arguments), $node->getTemplateLine());
 	}
+
+
+	private function functionHtmlClasses(FunctionExpression $node): FunctionExpression
+	{
+		$res = [];
+		$arguments = $node->getNode('arguments');
+		foreach ($arguments as $argument) {
+			if ($argument instanceof ArrayExpression) {
+				foreach ($argument->getKeyValuePairs() as ['key' => $key, 'value' => $value]) {
+					$res[] = new ConditionalExpression(
+						$value,
+						$key,
+						new ConstantExpression(null, $argument->getTemplateLine()),
+						$argument->getTemplateLine()
+					);
+				}
+			} else {
+				$res[] = $argument;
+			}
+		}
+		$arguments->setNodes($res);
+		return $node;
+	}
 }

tests/fixtures-twig/functions/html_classes.latte

@@ -1 +1 @@
-<p class="{html_classes(a-class, another-class, [errored => $object->errored, finished => $object->finished, pending => $object->pending])}">How are you doing?</p>
+<p n:class="a-class, another-class, $object->errored ? errored, $object->finished ? finished, $object->pending ? pending">How are you doing?</p>