Add support for argument unpacking

CHANGELOG

@@ -1,5 +1,6 @@
 # 3.15.0 (2024-XX-XX)
 
+ * Add support for argument unpackaging
  * Add JSON support for the file extension escaping strategy
  * Support Markup instances (and any other \Stringable) as dynamic mapping keys
  * Deprecate the `sandbox` tag

doc/templates.rst

@@ -815,14 +815,21 @@ The following operators don't fit into any of the other categories:
       {# returns the value of foo if it is defined and not null, 'no' otherwise #}
       {{ foo ?? 'no' }}
 
-* ``...``: The spread operator can be used to expand sequences or mappings (it
+* ``...``: The spread operator can be used to expand sequences or mappings or
-  cannot be used to expand the arguments of a function call):
+  to expand the arguments of a function call:
 
   .. code-block:: twig
 
       {% set numbers = [1, 2, ...moreNumbers] %}
       {% set ratings = {'foo': 10, 'bar': 5, ...moreRatings} %}
 
+      {{ 'Hello %s %s!'|format(...['Fabien', 'Potencier']) }}
+
+  .. versionadded:: 3.15
+
+    Support for expanding the arguments of a function call was introduced in
+    Twig 3.15.
+
 Operators
 ~~~~~~~~~
 

src/ExpressionParser.php

@@ -30,6 +30,7 @@ use Twig\Node\Expression\Unary\AbstractUnary;
 use Twig\Node\Expression\Unary\NegUnary;
 use Twig\Node\Expression\Unary\NotUnary;
 use Twig\Node\Expression\Unary\PosUnary;
+use Twig\Node\Expression\Unary\SpreadUnary;
 use Twig\Node\Node;
 
 /**
@@ -618,6 +619,7 @@ class ExpressionParser
         $stream = $this->parser->getStream();
 
         $stream->expect(Token::PUNCTUATION_TYPE, '(', 'A list of arguments must begin with an opening parenthesis');
+        $hasSpread = false;
         while (!$stream->test(Token::PUNCTUATION_TYPE, ')')) {
             if ($args) {
                 $stream->expect(Token::PUNCTUATION_TYPE, ',', 'Arguments must be separated by a comma');
@@ -632,7 +634,14 @@ class ExpressionParser
                 $token = $stream->expect(Token::NAME_TYPE, null, 'An argument must be a name');
                 $value = new NameExpression($token->getValue(), $this->parser->getCurrentToken()->getLine());
             } else {
-                $value = $this->parseExpression(0, $allowArrow);
+                if ($stream->nextIf(Token::SPREAD_TYPE)) {
+                    $hasSpread = true;
+                    $value = new SpreadUnary($this->parseExpression(0, $allowArrow), $stream->getCurrent()->getLine());
+                } elseif ($hasSpread) {
+                    throw new SyntaxError('Normal arguments must be placed before argument unpacking.', $stream->getCurrent()->getLine(), $stream->getSourceContext());
+                } else {
+                    $value = $this->parseExpression(0, $allowArrow);
+                }
             }
 
             $name = null;

src/Node/Expression/Unary/SpreadUnary.php

@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Node\Expression\Unary;
+
+use Twig\Compiler;
+
+final class SpreadUnary extends AbstractUnary
+{
+    public function operator(Compiler $compiler): Compiler
+    {
+        return $compiler->raw('...');
+    }
+}

tests/Fixtures/expressions/call_argument_unpacking.test

@@ -0,0 +1,16 @@
+--TEST--
+Twig supports array unpacking for function calls
+--TEMPLATE--
+{{ '%s %s %s'|format(...[1, 2, 3]) }}
+{{ '%s %s %s'|format(...[1], ...[2, 3]) }}
+{{ '%s %s %s'|format(1, ...[2, 3]) }}
+{{ '%s %s %s'|format(1, ...[2], ...[3]) }}
+{{ '%s %s %s'|format(...it) }}
+--DATA--
+return ['it' => new \ArrayIterator([1, 2, 3])]
+--EXPECT--
+1 2 3
+1 2 3
+1 2 3
+1 2 3
+1 2 3

tests/Fixtures/expressions/call_argument_unpacking_before_normal.test

@@ -0,0 +1,8 @@
+--TEST--
+Twig supports array unpacking for function calls (but not before normal args)
+--TEMPLATE--
+{{ '%s %s %s'|format(...[1, 2], 3) }}
+--DATA--
+return []
+--EXCEPTION--
+Twig\Error\SyntaxError: Normal arguments must be placed before argument unpacking in "index.twig" at line 2.