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<?php $pattern="\(((?>[^()]+)|(?R))*\)"; //$str="(def a (x) (+ 1 x))(print (a 1))"; $str="(aaa)"; preg_match_all($pattern,$str,$out); var_dump($out);
Output for 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Warning: preg_match_all(): Delimiter must not be alphanumeric, backslash, or NUL in /in/X0r8p on line 9 NULL
Output for 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28
Warning: preg_match_all(): Delimiter must not be alphanumeric or backslash in /in/X0r8p on line 9 NULL
Output for 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6
Warning: preg_match_all(): Delimiter must not be alphanumeric or backslash in /in/X0r8p on line 9 array(0) { }
Output for 4.3.0 - 4.3.10
Warning: Delimiter must not be alphanumeric or backslash in /in/X0r8p on line 9 array(0) { }
preferences:
317.76 ms | 401 KiB | 460 Q