Use short array deconstruction syntax.

Author: derrabus

Lexer.php

@@ -62,7 +62,7 @@ public function tokenize($expression)
                     throw new SyntaxError(sprintf('Unexpected "%s".', $expression[$cursor]), $cursor, $expression);
                 }
 
-                list($expect, $cur) = array_pop($brackets);
+                [$expect, $cur] = array_pop($brackets);
                 if ($expression[$cursor] != strtr($expect, '([{', ')]}')) {
                     throw new SyntaxError(sprintf('Unclosed "%s".', $expect), $cur, $expression);
                 }
@@ -94,7 +94,7 @@ public function tokenize($expression)
         $tokens[] = new Token(Token::EOF_TYPE, null, $cursor + 1);
 
         if (!empty($brackets)) {
-            list($expect, $cur) = array_pop($brackets);
+            [$expect, $cur] = array_pop($brackets);
             throw new SyntaxError(sprintf('Unclosed "%s".', $expect), $cur, $expression);
         }