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  1. <?php
  2.  
  3. $pattern = <<<EOT
  4. /
  5. (?(FOOBAR)
  6. (?<T_NUM> [0-9] )
  7. )
  8. ^(?&T_NUM)$
  9. /x
  10. EOT;
  11. $text = '1';
  12.  
  13. if (preg_match($pattern, $text))
  14. {
  15.         echo "matched!\n";
  16. }
  17. else
  18. {
  19.         echo "no match!\n";
  20. }
Success #stdin #stdout 0.02s 13064KB
comments (?)
stdin 
Standard input is empty
stdout 
Warning: preg_match(): Compilation failed: reference to non-existent subpattern at offset 11 in /home/Yhv4Oo/prog.php on line 13
no match!
https://ideone.com/plXWY
language:
PHP (php 7.3.5)
created:
12 years ago
visibility:
public

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