Turn an indented text list to a multi-dimensional array.

tree_text.php

<?php
$tree_text = function(string $text): array {
	$lines = explode(PHP_EOL, $text);
	$levels = array_map(function($line){
		$level = 0;
		while(substr($line, $level, 1) == "\t") {
			$level++;
		}
		return $level;
	}, $lines);
	array_walk($lines, function(&$line, $key, $level) {
		$line = trim(substr($line, $level[$key]));
	}, $levels);
	reset($levels);
	reset($lines);

	$curr_level = 0;
	$attempt = 0;
	$generate_tree = function() use (
		&$generate_tree, &$lines, &$levels, &$curr_level, &$attempt
	) {
		$tree = [];
		while(key($lines) !== null && $attempt <= 1000) {
			$attempt++;
			switch($curr_level <=> current($levels)) {
				case 0:
					$tree[current($lines)] = [];
					next($lines);
					next($levels);
					break;
				case -1:
					$curr_level++;
					end($tree);
					$tree[key($tree)] = $generate_tree();
					break;
				case 1:
					$curr_level--;
					break 2;
			}
		}
		if(array_filter($tree))
			return $tree;
		else
			return array_keys($tree);
	};
	
	return $generate_tree();
};

Example of expected input and output:

$text = <<<TEXT
Henlo
	lizer
helllo
	you
	STINKY
		LIZARD
go
	eat
		a fly
		ugly
TEXT;

array(3) {
  ["Henlo"]=>
  array(1) {
    [0]=>
    string(5) "lizer"
  }
  ["helllo"]=>
  array(2) {
    ["you"]=>
    array(0) {
    }
    ["STINKY"]=>
    array(1) {
      [0]=>
      string(6) "LIZARD"
    }
  }
  ["go"]=>
  array(1) {
    ["eat"]=>
    array(2) {
      [0]=>
      string(5) "a fly"
      [1]=>
      string(4) "ugly"
    }
  }
}