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  1. <?php
  2. 	//PHP regex recursivo
  3. 	// https://pt.stackoverflow.com/q/200254/53463
  4.  
  5. 	function validar($expr) {
  6. 		$oper   = '[-+*\/]';           //um operador matemático
  7. 		$numero = '(?:- ?)?\d*\.?\d+'; //float
  8. 		$nomes  = '(?:var|perg|ind)';  //nomes de função
  9.  
  10. 		$recurse= '(?1)';
  11.  
  12. 		$parens = '\(' . $recurse . '\)';
  13. 		$funcao = "$nomes?$parens";
  14.  
  15. 		$x = "(?:$numero|$funcao)";
  16. 		$s = $x . "(?:$oper$recurse)*";
  17.  
  18. 		$regex = "/^($s)$/";
  19. 			 //=> /^((?:(?:- ?)?\d*\.?\d+|(?:var|perg|ind)?\((?1)\))(?:[-+*\/](?1))*)$/
  20.  
  21. 		return preg_match( $regex, $expr);
  22. 	}
  23.  
  24.  
  25. 	//  EXEMPLOS
  26. 	$exemplos = [
  27. 			'9-8+',
  28. 			'(ind(10)+15)-10',
  29. 			'(ind(10)+15-10',
  30. 			'1000-(perg(25)*2)',
  31. 			'1000-perg(25)*2)',
  32. 			'1000-perg(25)*2',
  33. 			'25/var(1)',
  34. 			'12*2-(58+1)/5',
  35. 			'(perg(6)*perg(4)*)*1000000',
  36. 			'0'
  37. 		];
  38.  
  39. 	foreach ($exemplos as $expressao) {
  40. 		echo (validar($expressao) ? '✔️' : '✖️') . " $expressao\n";
  41. 	}
Success #stdin #stdout 0.01s 82944KB
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Standard input is empty
stdout
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✖️ 9-8+
✔️ (ind(10)+15)-10
✖️ (ind(10)+15-10
✔️ 1000-(perg(25)*2)
✖️ 1000-perg(25)*2)
✔️ 1000-perg(25)*2
✔️ 25/var(1)
✔️ 12*2-(58+1)/5
✖️ (perg(6)*perg(4)*)*1000000
✔️ 0
https://ideone.com/nHl0Mo
Validar expressão matemática
PHP regex recursivo
https://pt.stackoverflow.com/q/200254/53463
language:
PHP (php 7.3.5)
created:
6 years ago
visibility:
secret

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