something.txt

<?php
$str = "foo:arg1| arg2, bar:arg, baz";
var_dump(strToArray($str));
?>

array(3) {
  [0]=>
  array(2) {
    [0]=>
    string(3) "foo"
    [1]=>
    array(2) {
      [0]=>
      string(4) "arg1"
      [1]=>
      string(4) "arg2"
    }
  }
  [1]=>
  array(2) {
    [0]=>
    string(3) "bar"
    [1]=>
    array(1) {
      [0]=>
      string(3) "arg"
    }
  }
  [2]=>
  array(1) {
    [0]=>
    string(3) "baz"
  }
}

StringToArrayWithMultipleSplitsThingy.php

<?php
    function splitAndStrip($str, $del = ',')
    {
        $str = explode($del, $str);
        for ($i=0; $i < count($str); $i++)
        {
            $str[$i] = trim($str[$i]);
        }
        return $str;
    }
    
    function strToArray($str)
    {
        $arr = array();
        $str = splitAndStrip($str);
        
        for ($i=0; $i < count($str); $i++)
        {
            $arr[$i] = splitAndStrip($str[$i], ':');
            if(count($arr[$i]) > 1)
            {
                $arr[$i][1] = splitAndStrip($arr[$i][1], '|');
            }
            
        }
        return $arr;
    }