<?php
 
$texto = "Olá {cliente}, seja bem vindo ao site {site}!
Aqui você terá acesso as seguintes opções:
{opcoes}
 
Estes dados foram gerados automaticamente em {data}
Pela empresa {empresa}";
 
function recuperarTags($texto){
	$inicio = 0;
	$tags = [];
 
	while (($inicio = strpos($texto, "{", $inicio)) !== false) {
		$final = strpos($texto, '}', $inicio + 1);
		$tamanho = $final - $inicio;
		$tag = substr($texto, $inicio + 1, $tamanho - 1);
 
		$tags[] = $tag;
		$inicio += 1;
	}
	return $tags;
}
 
$tags = recuperarTags($texto);
foreach ($tags as $tag) {
    echo $tag ."\n";
}
 

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