1 <?php
2 
3 /*
4  * This file is part of Twig.
5  *
6  * (c) Fabien Potencier
7  * (c) Armin Ronacher
8  *
9  * For the full copyright and license information, please view the LICENSE
10  * file that was distributed with this source code.
11  */
12 
13 namespace Twig;
14 
15 use Twig\Error\SyntaxError;
16 use Twig\Node\Expression\AbstractExpression;
17 use Twig\Node\Expression\ArrayExpression;
18 use Twig\Node\Expression\ArrowFunctionExpression;
19 use Twig\Node\Expression\AssignNameExpression;
20 use Twig\Node\Expression\Binary\ConcatBinary;
21 use Twig\Node\Expression\BlockReferenceExpression;
22 use Twig\Node\Expression\ConditionalExpression;
23 use Twig\Node\Expression\ConstantExpression;
24 use Twig\Node\Expression\GetAttrExpression;
25 use Twig\Node\Expression\MethodCallExpression;
26 use Twig\Node\Expression\NameExpression;
27 use Twig\Node\Expression\ParentExpression;
28 use Twig\Node\Expression\TestExpression;
29 use Twig\Node\Expression\Unary\NegUnary;
30 use Twig\Node\Expression\Unary\NotUnary;
31 use Twig\Node\Expression\Unary\PosUnary;
32 use Twig\Node\Node;
33 
34 /**
35  * Parses expressions.
36  *
37  * This parser implements a "Precedence climbing" algorithm.
38  *
39  * @see https://www.engr.mun.ca/~theo/Misc/exp_parsing.htm
40  * @see https://en.wikipedia.org/wiki/Operator-precedence_parser
41  *
42  * @author Fabien Potencier <fabien@symfony.com>
43  *
44  * @internal
45  */
46 class ExpressionParser
47 {
48     public const OPERATOR_LEFT = 1;
49     public const OPERATOR_RIGHT = 2;
50 
51     private $parser;
52     private $env;
53     private $unaryOperators;
54     private $binaryOperators;
55 
56     public function __construct(Parser $parser, Environment $env)
57     {
58         $this->parser = $parser;
59         $this->env = $env;
60         $this->unaryOperators = $env->getUnaryOperators();
61         $this->binaryOperators = $env->getBinaryOperators();
62     }
63 
64     public function parseExpression($precedence = 0, $allowArrow = false)
65     {
66         if ($allowArrow && $arrow = $this->parseArrow()) {
67             return $arrow;
68         }
69 
70         $expr = $this->getPrimary();
71         $token = $this->parser->getCurrentToken();
72         while ($this->isBinary($token) && $this->binaryOperators[$token->getValue()]['precedence'] >= $precedence) {
73             $op = $this->binaryOperators[$token->getValue()];
74             $this->parser->getStream()->next();
75 
76             if ('is not' === $token->getValue()) {
77                 $expr = $this->parseNotTestExpression($expr);
78             } elseif ('is' === $token->getValue()) {
79                 $expr = $this->parseTestExpression($expr);
80             } elseif (isset($op['callable'])) {
81                 $expr = $op['callable']($this->parser, $expr);
82             } else {
83                 $expr1 = $this->parseExpression(self::OPERATOR_LEFT === $op['associativity'] ? $op['precedence'] + 1 : $op['precedence']);
84                 $class = $op['class'];
85                 $expr = new $class($expr, $expr1, $token->getLine());
86             }
87 
88             $token = $this->parser->getCurrentToken();
89         }
90 
91         if (0 === $precedence) {
92             return $this->parseConditionalExpression($expr);
93         }
94 
95         return $expr;
96     }
97 
98     /**
99      * @return ArrowFunctionExpression|null
100      */
101     private function parseArrow()
102     {
103         $stream = $this->parser->getStream();
104 
105         // short array syntax (one argument, no parentheses)?
106         if ($stream->look(1)->test(/* Token::ARROW_TYPE */ 12)) {
107             $line = $stream->getCurrent()->getLine();
108             $token = $stream->expect(/* Token::NAME_TYPE */ 5);
109             $names = [new AssignNameExpression($token->getValue(), $token->getLine())];
110             $stream->expect(/* Token::ARROW_TYPE */ 12);
111 
112             return new ArrowFunctionExpression($this->parseExpression(0), new Node($names), $line);
113         }
114 
115         // first, determine if we are parsing an arrow function by finding => (long form)
116         $i = 0;
117         if (!$stream->look($i)->test(/* Token::PUNCTUATION_TYPE */ 9, '(')) {
118             return null;
119         }
120         ++$i;
121         while (true) {
122             // variable name
123             ++$i;
124             if (!$stream->look($i)->test(/* Token::PUNCTUATION_TYPE */ 9, ',')) {
125                 break;
126             }
127             ++$i;
128         }
129         if (!$stream->look($i)->test(/* Token::PUNCTUATION_TYPE */ 9, ')')) {
130             return null;
131         }
132         ++$i;
133         if (!$stream->look($i)->test(/* Token::ARROW_TYPE */ 12)) {
134             return null;
135         }
136 
137         // yes, let's parse it properly
138         $token = $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, '(');
139         $line = $token->getLine();
140 
141         $names = [];
142         while (true) {
143             $token = $stream->expect(/* Token::NAME_TYPE */ 5);
144             $names[] = new AssignNameExpression($token->getValue(), $token->getLine());
145 
146             if (!$stream->nextIf(/* Token::PUNCTUATION_TYPE */ 9, ',')) {
147                 break;
148             }
149         }
150         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ')');
151         $stream->expect(/* Token::ARROW_TYPE */ 12);
152 
153         return new ArrowFunctionExpression($this->parseExpression(0), new Node($names), $line);
154     }
155 
156     private function getPrimary(): AbstractExpression
157     {
158         $token = $this->parser->getCurrentToken();
159 
160         if ($this->isUnary($token)) {
161             $operator = $this->unaryOperators[$token->getValue()];
162             $this->parser->getStream()->next();
163             $expr = $this->parseExpression($operator['precedence']);
164             $class = $operator['class'];
165 
166             return $this->parsePostfixExpression(new $class($expr, $token->getLine()));
167         } elseif ($token->test(/* Token::PUNCTUATION_TYPE */ 9, '(')) {
168             $this->parser->getStream()->next();
169             $expr = $this->parseExpression();
170             $this->parser->getStream()->expect(/* Token::PUNCTUATION_TYPE */ 9, ')', 'An opened parenthesis is not properly closed');
171 
172             return $this->parsePostfixExpression($expr);
173         }
174 
175         return $this->parsePrimaryExpression();
176     }
177 
178     private function parseConditionalExpression($expr): AbstractExpression
179     {
180         while ($this->parser->getStream()->nextIf(/* Token::PUNCTUATION_TYPE */ 9, '?')) {
181             if (!$this->parser->getStream()->nextIf(/* Token::PUNCTUATION_TYPE */ 9, ':')) {
182                 $expr2 = $this->parseExpression();
183                 if ($this->parser->getStream()->nextIf(/* Token::PUNCTUATION_TYPE */ 9, ':')) {
184                     $expr3 = $this->parseExpression();
185                 } else {
186                     $expr3 = new ConstantExpression('', $this->parser->getCurrentToken()->getLine());
187                 }
188             } else {
189                 $expr2 = $expr;
190                 $expr3 = $this->parseExpression();
191             }
192 
193             $expr = new ConditionalExpression($expr, $expr2, $expr3, $this->parser->getCurrentToken()->getLine());
194         }
195 
196         return $expr;
197     }
198 
199     private function isUnary(Token $token): bool
200     {
201         return $token->test(/* Token::OPERATOR_TYPE */ 8) && isset($this->unaryOperators[$token->getValue()]);
202     }
203 
204     private function isBinary(Token $token): bool
205     {
206         return $token->test(/* Token::OPERATOR_TYPE */ 8) && isset($this->binaryOperators[$token->getValue()]);
207     }
208 
209     public function parsePrimaryExpression()
210     {
211         $token = $this->parser->getCurrentToken();
212         switch ($token->getType()) {
213             case /* Token::NAME_TYPE */ 5:
214                 $this->parser->getStream()->next();
215                 switch ($token->getValue()) {
216                     case 'true':
217                     case 'TRUE':
218                         $node = new ConstantExpression(true, $token->getLine());
219                         break;
220 
221                     case 'false':
222                     case 'FALSE':
223                         $node = new ConstantExpression(false, $token->getLine());
224                         break;
225 
226                     case 'none':
227                     case 'NONE':
228                     case 'null':
229                     case 'NULL':
230                         $node = new ConstantExpression(null, $token->getLine());
231                         break;
232 
233                     default:
234                         if ('(' === $this->parser->getCurrentToken()->getValue()) {
235                             $node = $this->getFunctionNode($token->getValue(), $token->getLine());
236                         } else {
237                             $node = new NameExpression($token->getValue(), $token->getLine());
238                         }
239                 }
240                 break;
241 
242             case /* Token::NUMBER_TYPE */ 6:
243                 $this->parser->getStream()->next();
244                 $node = new ConstantExpression($token->getValue(), $token->getLine());
245                 break;
246 
247             case /* Token::STRING_TYPE */ 7:
248             case /* Token::INTERPOLATION_START_TYPE */ 10:
249                 $node = $this->parseStringExpression();
250                 break;
251 
252             case /* Token::OPERATOR_TYPE */ 8:
253                 if (preg_match(Lexer::REGEX_NAME, $token->getValue(), $matches) && $matches[0] == $token->getValue()) {
254                     // in this context, string operators are variable names
255                     $this->parser->getStream()->next();
256                     $node = new NameExpression($token->getValue(), $token->getLine());
257                     break;
258                 } elseif (isset($this->unaryOperators[$token->getValue()])) {
259                     $class = $this->unaryOperators[$token->getValue()]['class'];
260 
261                     $ref = new \ReflectionClass($class);
262                     if (!(\in_array($ref->getName(), [NegUnary::class, PosUnary::class, 'Twig_Node_Expression_Unary_Neg', 'Twig_Node_Expression_Unary_Pos'])
263                         || $ref->isSubclassOf(NegUnary::class) || $ref->isSubclassOf(PosUnary::class)
264                         || $ref->isSubclassOf('Twig_Node_Expression_Unary_Neg') || $ref->isSubclassOf('Twig_Node_Expression_Unary_Pos'))
265                     ) {
266                         throw new SyntaxError(sprintf('Unexpected unary operator "%s".', $token->getValue()), $token->getLine(), $this->parser->getStream()->getSourceContext());
267                     }
268 
269                     $this->parser->getStream()->next();
270                     $expr = $this->parsePrimaryExpression();
271 
272                     $node = new $class($expr, $token->getLine());
273                     break;
274                 }
275 
276                 // no break
277             default:
278                 if ($token->test(/* Token::PUNCTUATION_TYPE */ 9, '[')) {
279                     $node = $this->parseArrayExpression();
280                 } elseif ($token->test(/* Token::PUNCTUATION_TYPE */ 9, '{')) {
281                     $node = $this->parseHashExpression();
282                 } elseif ($token->test(/* Token::OPERATOR_TYPE */ 8, '=') && ('==' === $this->parser->getStream()->look(-1)->getValue() || '!=' === $this->parser->getStream()->look(-1)->getValue())) {
283                     throw new SyntaxError(sprintf('Unexpected operator of value "%s". Did you try to use "===" or "!==" for strict comparison? Use "is same as(value)" instead.', $token->getValue()), $token->getLine(), $this->parser->getStream()->getSourceContext());
284                 } else {
285                     throw new SyntaxError(sprintf('Unexpected token "%s" of value "%s".', Token::typeToEnglish($token->getType()), $token->getValue()), $token->getLine(), $this->parser->getStream()->getSourceContext());
286                 }
287         }
288 
289         return $this->parsePostfixExpression($node);
290     }
291 
292     public function parseStringExpression()
293     {
294         $stream = $this->parser->getStream();
295 
296         $nodes = [];
297         // a string cannot be followed by another string in a single expression
298         $nextCanBeString = true;
299         while (true) {
300             if ($nextCanBeString && $token = $stream->nextIf(/* Token::STRING_TYPE */ 7)) {
301                 $nodes[] = new ConstantExpression($token->getValue(), $token->getLine());
302                 $nextCanBeString = false;
303             } elseif ($stream->nextIf(/* Token::INTERPOLATION_START_TYPE */ 10)) {
304                 $nodes[] = $this->parseExpression();
305                 $stream->expect(/* Token::INTERPOLATION_END_TYPE */ 11);
306                 $nextCanBeString = true;
307             } else {
308                 break;
309             }
310         }
311 
312         $expr = array_shift($nodes);
313         foreach ($nodes as $node) {
314             $expr = new ConcatBinary($expr, $node, $node->getTemplateLine());
315         }
316 
317         return $expr;
318     }
319 
320     public function parseArrayExpression()
321     {
322         $stream = $this->parser->getStream();
323         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, '[', 'An array element was expected');
324 
325         $node = new ArrayExpression([], $stream->getCurrent()->getLine());
326         $first = true;
327         while (!$stream->test(/* Token::PUNCTUATION_TYPE */ 9, ']')) {
328             if (!$first) {
329                 $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ',', 'An array element must be followed by a comma');
330 
331                 // trailing ,?
332                 if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, ']')) {
333                     break;
334                 }
335             }
336             $first = false;
337 
338             $node->addElement($this->parseExpression());
339         }
340         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ']', 'An opened array is not properly closed');
341 
342         return $node;
343     }
344 
345     public function parseHashExpression()
346     {
347         $stream = $this->parser->getStream();
348         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, '{', 'A hash element was expected');
349 
350         $node = new ArrayExpression([], $stream->getCurrent()->getLine());
351         $first = true;
352         while (!$stream->test(/* Token::PUNCTUATION_TYPE */ 9, '}')) {
353             if (!$first) {
354                 $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ',', 'A hash value must be followed by a comma');
355 
356                 // trailing ,?
357                 if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, '}')) {
358                     break;
359                 }
360             }
361             $first = false;
362 
363             // a hash key can be:
364             //
365             //  * a number -- 12
366             //  * a string -- 'a'
367             //  * a name, which is equivalent to a string -- a
368             //  * an expression, which must be enclosed in parentheses -- (1 + 2)
369             if ($token = $stream->nextIf(/* Token::NAME_TYPE */ 5)) {
370                 $key = new ConstantExpression($token->getValue(), $token->getLine());
371 
372                 // {a} is a shortcut for {a:a}
373                 if ($stream->test(Token::PUNCTUATION_TYPE, [',', '}'])) {
374                     $value = new NameExpression($key->getAttribute('value'), $key->getTemplateLine());
375                     $node->addElement($value, $key);
376                     continue;
377                 }
378             } elseif (($token = $stream->nextIf(/* Token::STRING_TYPE */ 7)) || $token = $stream->nextIf(/* Token::NUMBER_TYPE */ 6)) {
379                 $key = new ConstantExpression($token->getValue(), $token->getLine());
380             } elseif ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, '(')) {
381                 $key = $this->parseExpression();
382             } else {
383                 $current = $stream->getCurrent();
384 
385                 throw new SyntaxError(sprintf('A hash key must be a quoted string, a number, a name, or an expression enclosed in parentheses (unexpected token "%s" of value "%s".', Token::typeToEnglish($current->getType()), $current->getValue()), $current->getLine(), $stream->getSourceContext());
386             }
387 
388             $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ':', 'A hash key must be followed by a colon (:)');
389             $value = $this->parseExpression();
390 
391             $node->addElement($value, $key);
392         }
393         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, '}', 'An opened hash is not properly closed');
394 
395         return $node;
396     }
397 
398     public function parsePostfixExpression($node)
399     {
400         while (true) {
401             $token = $this->parser->getCurrentToken();
402             if (/* Token::PUNCTUATION_TYPE */ 9 == $token->getType()) {
403                 if ('.' == $token->getValue() || '[' == $token->getValue()) {
404                     $node = $this->parseSubscriptExpression($node);
405                 } elseif ('|' == $token->getValue()) {
406                     $node = $this->parseFilterExpression($node);
407                 } else {
408                     break;
409                 }
410             } else {
411                 break;
412             }
413         }
414 
415         return $node;
416     }
417 
418     public function getFunctionNode($name, $line)
419     {
420         switch ($name) {
421             case 'parent':
422                 $this->parseArguments();
423                 if (!\count($this->parser->getBlockStack())) {
424                     throw new SyntaxError('Calling "parent" outside a block is forbidden.', $line, $this->parser->getStream()->getSourceContext());
425                 }
426 
427                 if (!$this->parser->getParent() && !$this->parser->hasTraits()) {
428                     throw new SyntaxError('Calling "parent" on a template that does not extend nor "use" another template is forbidden.', $line, $this->parser->getStream()->getSourceContext());
429                 }
430 
431                 return new ParentExpression($this->parser->peekBlockStack(), $line);
432             case 'block':
433                 $args = $this->parseArguments();
434                 if (\count($args) < 1) {
435                     throw new SyntaxError('The "block" function takes one argument (the block name).', $line, $this->parser->getStream()->getSourceContext());
436                 }
437 
438                 return new BlockReferenceExpression($args->getNode(0), \count($args) > 1 ? $args->getNode(1) : null, $line);
439             case 'attribute':
440                 $args = $this->parseArguments();
441                 if (\count($args) < 2) {
442                     throw new SyntaxError('The "attribute" function takes at least two arguments (the variable and the attributes).', $line, $this->parser->getStream()->getSourceContext());
443                 }
444 
445                 return new GetAttrExpression($args->getNode(0), $args->getNode(1), \count($args) > 2 ? $args->getNode(2) : null, Template::ANY_CALL, $line);
446             default:
447                 if (null !== $alias = $this->parser->getImportedSymbol('function', $name)) {
448                     $arguments = new ArrayExpression([], $line);
449                     foreach ($this->parseArguments() as $n) {
450                         $arguments->addElement($n);
451                     }
452 
453                     $node = new MethodCallExpression($alias['node'], $alias['name'], $arguments, $line);
454                     $node->setAttribute('safe', true);
455 
456                     return $node;
457                 }
458 
459                 $args = $this->parseArguments(true);
460                 $class = $this->getFunctionNodeClass($name, $line);
461 
462                 return new $class($name, $args, $line);
463         }
464     }
465 
466     public function parseSubscriptExpression($node)
467     {
468         $stream = $this->parser->getStream();
469         $token = $stream->next();
470         $lineno = $token->getLine();
471         $arguments = new ArrayExpression([], $lineno);
472         $type = Template::ANY_CALL;
473         if ('.' == $token->getValue()) {
474             $token = $stream->next();
475             if (
476                 /* Token::NAME_TYPE */ 5 == $token->getType()
477                 ||
478                 /* Token::NUMBER_TYPE */ 6 == $token->getType()
479                 ||
480                 (/* Token::OPERATOR_TYPE */ 8 == $token->getType() && preg_match(Lexer::REGEX_NAME, $token->getValue()))
481             ) {
482                 $arg = new ConstantExpression($token->getValue(), $lineno);
483 
484                 if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, '(')) {
485                     $type = Template::METHOD_CALL;
486                     foreach ($this->parseArguments() as $n) {
487                         $arguments->addElement($n);
488                     }
489                 }
490             } else {
491                 throw new SyntaxError(sprintf('Expected name or number, got value "%s" of type %s.', $token->getValue(), Token::typeToEnglish($token->getType())), $lineno, $stream->getSourceContext());
492             }
493 
494             if ($node instanceof NameExpression && null !== $this->parser->getImportedSymbol('template', $node->getAttribute('name'))) {
495                 if (!$arg instanceof ConstantExpression) {
496                     throw new SyntaxError(sprintf('Dynamic macro names are not supported (called on "%s").', $node->getAttribute('name')), $token->getLine(), $stream->getSourceContext());
497                 }
498 
499                 $name = $arg->getAttribute('value');
500 
501                 $node = new MethodCallExpression($node, 'macro_'.$name, $arguments, $lineno);
502                 $node->setAttribute('safe', true);
503 
504                 return $node;
505             }
506         } else {
507             $type = Template::ARRAY_CALL;
508 
509             // slice?
510             $slice = false;
511             if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, ':')) {
512                 $slice = true;
513                 $arg = new ConstantExpression(0, $token->getLine());
514             } else {
515                 $arg = $this->parseExpression();
516             }
517 
518             if ($stream->nextIf(/* Token::PUNCTUATION_TYPE */ 9, ':')) {
519                 $slice = true;
520             }
521 
522             if ($slice) {
523                 if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, ']')) {
524                     $length = new ConstantExpression(null, $token->getLine());
525                 } else {
526                     $length = $this->parseExpression();
527                 }
528 
529                 $class = $this->getFilterNodeClass('slice', $token->getLine());
530                 $arguments = new Node([$arg, $length]);
531                 $filter = new $class($node, new ConstantExpression('slice', $token->getLine()), $arguments, $token->getLine());
532 
533                 $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ']');
534 
535                 return $filter;
536             }
537 
538             $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ']');
539         }
540 
541         return new GetAttrExpression($node, $arg, $arguments, $type, $lineno);
542     }
543 
544     public function parseFilterExpression($node)
545     {
546         $this->parser->getStream()->next();
547 
548         return $this->parseFilterExpressionRaw($node);
549     }
550 
551     public function parseFilterExpressionRaw($node, $tag = null)
552     {
553         while (true) {
554             $token = $this->parser->getStream()->expect(/* Token::NAME_TYPE */ 5);
555 
556             $name = new ConstantExpression($token->getValue(), $token->getLine());
557             if (!$this->parser->getStream()->test(/* Token::PUNCTUATION_TYPE */ 9, '(')) {
558                 $arguments = new Node();
559             } else {
560                 $arguments = $this->parseArguments(true, false, true);
561             }
562 
563             $class = $this->getFilterNodeClass($name->getAttribute('value'), $token->getLine());
564 
565             $node = new $class($node, $name, $arguments, $token->getLine(), $tag);
566 
567             if (!$this->parser->getStream()->test(/* Token::PUNCTUATION_TYPE */ 9, '|')) {
568                 break;
569             }
570 
571             $this->parser->getStream()->next();
572         }
573 
574         return $node;
575     }
576 
577     /**
578      * Parses arguments.
579      *
580      * @param bool $namedArguments Whether to allow named arguments or not
581      * @param bool $definition     Whether we are parsing arguments for a function definition
582      *
583      * @return Node
584      *
585      * @throws SyntaxError
586      */
587     public function parseArguments($namedArguments = false, $definition = false, $allowArrow = false)
588     {
589         $args = [];
590         $stream = $this->parser->getStream();
591 
592         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, '(', 'A list of arguments must begin with an opening parenthesis');
593         while (!$stream->test(/* Token::PUNCTUATION_TYPE */ 9, ')')) {
594             if (!empty($args)) {
595                 $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ',', 'Arguments must be separated by a comma');
596 
597                 // if the comma above was a trailing comma, early exit the argument parse loop
598                 if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, ')')) {
599                     break;
600                 }
601             }
602 
603             if ($definition) {
604                 $token = $stream->expect(/* Token::NAME_TYPE */ 5, null, 'An argument must be a name');
605                 $value = new NameExpression($token->getValue(), $this->parser->getCurrentToken()->getLine());
606             } else {
607                 $value = $this->parseExpression(0, $allowArrow);
608             }
609 
610             $name = null;
611             if ($namedArguments && $token = $stream->nextIf(/* Token::OPERATOR_TYPE */ 8, '=')) {
612                 if (!$value instanceof NameExpression) {
613                     throw new SyntaxError(sprintf('A parameter name must be a string, "%s" given.', \get_class($value)), $token->getLine(), $stream->getSourceContext());
614                 }
615                 $name = $value->getAttribute('name');
616 
617                 if ($definition) {
618                     $value = $this->parsePrimaryExpression();
619 
620                     if (!$this->checkConstantExpression($value)) {
621                         throw new SyntaxError('A default value for an argument must be a constant (a boolean, a string, a number, or an array).', $token->getLine(), $stream->getSourceContext());
622                     }
623                 } else {
624                     $value = $this->parseExpression(0, $allowArrow);
625                 }
626             }
627 
628             if ($definition) {
629                 if (null === $name) {
630                     $name = $value->getAttribute('name');
631                     $value = new ConstantExpression(null, $this->parser->getCurrentToken()->getLine());
632                 }
633                 $args[$name] = $value;
634             } else {
635                 if (null === $name) {
636                     $args[] = $value;
637                 } else {
638                     $args[$name] = $value;
639                 }
640             }
641         }
642         $stream->expect(/* Token::PUNCTUATION_TYPE */ 9, ')', 'A list of arguments must be closed by a parenthesis');
643 
644         return new Node($args);
645     }
646 
647     public function parseAssignmentExpression()
648     {
649         $stream = $this->parser->getStream();
650         $targets = [];
651         while (true) {
652             $token = $this->parser->getCurrentToken();
653             if ($stream->test(/* Token::OPERATOR_TYPE */ 8) && preg_match(Lexer::REGEX_NAME, $token->getValue())) {
654                 // in this context, string operators are variable names
655                 $this->parser->getStream()->next();
656             } else {
657                 $stream->expect(/* Token::NAME_TYPE */ 5, null, 'Only variables can be assigned to');
658             }
659             $value = $token->getValue();
660             if (\in_array(strtr($value, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), ['true', 'false', 'none', 'null'])) {
661                 throw new SyntaxError(sprintf('You cannot assign a value to "%s".', $value), $token->getLine(), $stream->getSourceContext());
662             }
663             $targets[] = new AssignNameExpression($value, $token->getLine());
664 
665             if (!$stream->nextIf(/* Token::PUNCTUATION_TYPE */ 9, ',')) {
666                 break;
667             }
668         }
669 
670         return new Node($targets);
671     }
672 
673     public function parseMultitargetExpression()
674     {
675         $targets = [];
676         while (true) {
677             $targets[] = $this->parseExpression();
678             if (!$this->parser->getStream()->nextIf(/* Token::PUNCTUATION_TYPE */ 9, ',')) {
679                 break;
680             }
681         }
682 
683         return new Node($targets);
684     }
685 
686     private function parseNotTestExpression(Node $node): NotUnary
687     {
688         return new NotUnary($this->parseTestExpression($node), $this->parser->getCurrentToken()->getLine());
689     }
690 
691     private function parseTestExpression(Node $node): TestExpression
692     {
693         $stream = $this->parser->getStream();
694         list($name, $test) = $this->getTest($node->getTemplateLine());
695 
696         $class = $this->getTestNodeClass($test);
697         $arguments = null;
698         if ($stream->test(/* Token::PUNCTUATION_TYPE */ 9, '(')) {
699             $arguments = $this->parseArguments(true);
700         } elseif ($test->hasOneMandatoryArgument()) {
701             $arguments = new Node([0 => $this->parsePrimaryExpression()]);
702         }
703 
704         if ('defined' === $name && $node instanceof NameExpression && null !== $alias = $this->parser->getImportedSymbol('function', $node->getAttribute('name'))) {
705             $node = new MethodCallExpression($alias['node'], $alias['name'], new ArrayExpression([], $node->getTemplateLine()), $node->getTemplateLine());
706             $node->setAttribute('safe', true);
707         }
708 
709         return new $class($node, $name, $arguments, $this->parser->getCurrentToken()->getLine());
710     }
711 
712     private function getTest(int $line): array
713     {
714         $stream = $this->parser->getStream();
715         $name = $stream->expect(/* Token::NAME_TYPE */ 5)->getValue();
716 
717         if ($test = $this->env->getTest($name)) {
718             return [$name, $test];
719         }
720 
721         if ($stream->test(/* Token::NAME_TYPE */ 5)) {
722             // try 2-words tests
723             $name = $name.' '.$this->parser->getCurrentToken()->getValue();
724 
725             if ($test = $this->env->getTest($name)) {
726                 $stream->next();
727 
728                 return [$name, $test];
729             }
730         }
731 
732         $e = new SyntaxError(sprintf('Unknown "%s" test.', $name), $line, $stream->getSourceContext());
733         $e->addSuggestions($name, array_keys($this->env->getTests()));
734 
735         throw $e;
736     }
737 
738     private function getTestNodeClass(TwigTest $test): string
739     {
740         if ($test->isDeprecated()) {
741             $stream = $this->parser->getStream();
742             $message = sprintf('Twig Test "%s" is deprecated', $test->getName());
743 
744             if (!\is_bool($test->getDeprecatedVersion())) {
745                 $message .= sprintf(' since version %s', $test->getDeprecatedVersion());
746             }
747             if ($test->getAlternative()) {
748                 $message .= sprintf('. Use "%s" instead', $test->getAlternative());
749             }
750             $src = $stream->getSourceContext();
751             $message .= sprintf(' in %s at line %d.', $src->getPath() ?: $src->getName(), $stream->getCurrent()->getLine());
752 
753             @trigger_error($message, \E_USER_DEPRECATED);
754         }
755 
756         return $test->getNodeClass();
757     }
758 
759     private function getFunctionNodeClass(string $name, int $line): string
760     {
761         if (false === $function = $this->env->getFunction($name)) {
762             $e = new SyntaxError(sprintf('Unknown "%s" function.', $name), $line, $this->parser->getStream()->getSourceContext());
763             $e->addSuggestions($name, array_keys($this->env->getFunctions()));
764 
765             throw $e;
766         }
767 
768         if ($function->isDeprecated()) {
769             $message = sprintf('Twig Function "%s" is deprecated', $function->getName());
770             if (!\is_bool($function->getDeprecatedVersion())) {
771                 $message .= sprintf(' since version %s', $function->getDeprecatedVersion());
772             }
773             if ($function->getAlternative()) {
774                 $message .= sprintf('. Use "%s" instead', $function->getAlternative());
775             }
776             $src = $this->parser->getStream()->getSourceContext();
777             $message .= sprintf(' in %s at line %d.', $src->getPath() ?: $src->getName(), $line);
778 
779             @trigger_error($message, \E_USER_DEPRECATED);
780         }
781 
782         return $function->getNodeClass();
783     }
784 
785     private function getFilterNodeClass(string $name, int $line): string
786     {
787         if (false === $filter = $this->env->getFilter($name)) {
788             $e = new SyntaxError(sprintf('Unknown "%s" filter.', $name), $line, $this->parser->getStream()->getSourceContext());
789             $e->addSuggestions($name, array_keys($this->env->getFilters()));
790 
791             throw $e;
792         }
793 
794         if ($filter->isDeprecated()) {
795             $message = sprintf('Twig Filter "%s" is deprecated', $filter->getName());
796             if (!\is_bool($filter->getDeprecatedVersion())) {
797                 $message .= sprintf(' since version %s', $filter->getDeprecatedVersion());
798             }
799             if ($filter->getAlternative()) {
800                 $message .= sprintf('. Use "%s" instead', $filter->getAlternative());
801             }
802             $src = $this->parser->getStream()->getSourceContext();
803             $message .= sprintf(' in %s at line %d.', $src->getPath() ?: $src->getName(), $line);
804 
805             @trigger_error($message, \E_USER_DEPRECATED);
806         }
807 
808         return $filter->getNodeClass();
809     }
810 
811     // checks that the node only contains "constant" elements
812     private function checkConstantExpression(Node $node): bool
813     {
814         if (!($node instanceof ConstantExpression || $node instanceof ArrayExpression
815             || $node instanceof NegUnary || $node instanceof PosUnary
816         )) {
817             return false;
818         }
819 
820         foreach ($node as $n) {
821             if (!$this->checkConstantExpression($n)) {
822                 return false;
823             }
824         }
825 
826         return true;
827     }
828 }
829 
830 class_alias('Twig\ExpressionParser', 'Twig_ExpressionParser');
831