- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$string = '{IF bla}Text 1{ELSEIF ble}Text 2 {IF bli}Text 2.1{ELSE blo}Text 2.1{ENDIF} Main text end{/ENDIF}';
var_dump(preg_match('#\{IF [^}]*\}[^{]*\{ENDIF\}#is',$string,$m));
var_dump($m);