I have some big trouble for this allowing this Regex :
{{{ hello{{there}} }}}
My problem is essentially to distinguish between double and triple brackets since the notation use a braket... I have tried
\{{2} /*Accept only two brakets --- Does NOT work*/
to allow 2 brakets but it does no work at all.
Is a Regex specialist can tell me a trick ? Thanks in advance
To discriminate between triple and double braces you need to use lookarounds.
To only match double opening braces, use
(?<!{){{2}(?!{)
Here, (?<!{) is a negative lookbehind that makes sure there is no { before the first { and (?!{) is a negative lookahead that makes sure there is no { after the second {. See regex demo here.
To only match triple opening braces use
(?<!{){{3}(?!{)
Just use } in all the above expressions to match closing braces.
Note that there is no need to escape { and } in PHP regex, the engine is smart enough to know they are not part of the limiting quantifier.
To get all substrings between {{{ and }}}, you can use
'~(?<!{){{{(?!{)\s*(.*?)\s*(?<!})}}}(?!})~s'
See the 3rd regex demo. PHP code:
$re = '~(?<!{){{{(?!{)\s*(.*?)\s*(?<!})}}}(?!})~s';
$str = "{{{ hello{{there}} }}} {{{good {{morning}} }}}";
preg_match_all($re, $str, $matches);
print_r($matches[1]);
Output:
[0] => hello{{there}}
[1] => good {{morning}}
Also note that in case you have no quadruple {s and }s, you can omit the lookarounds and use '~{{{\s*(.*?)\s*}}}~s'.