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Question

I am trying to create a recursive tokenizer that would handle this string and convert it into a multidimensional array.

Input:

a,b,c(a,b,c),d(a,b(a,b)),e

Output

$r = [
    'a' => 'a',
    'b' => 'b',
    'c' => [
        'a' => 'a',
        'b' => 'b',
        'c' => 'c'
        ],
    'd' => [
        'a' => 'a',
        'b' => [
            'a',
            'b'
            ]
        ],
    'e' => 'e'
    ];

Any ideas?

Answer 1

I would tokenize your string first and then convert it into a JSON string and decode that one to an associative array. I build a little function to do that:

$str = 'a,b,c(a,b,c),d(a,b(a,b)),e';

function parse($str) {
    preg_match_all('/[a-z\\(\\)]/', $str, $matches);

    $jsonStr = '{';
    $tokensCount = count($matches[0]);
    $tokens = $matches[0];

    for($i = 0; $i < $tokensCount; ++$i) {
        $nextToken = isset($tokens[$i+1])?trim($tokens[$i+1]):false;
        $currentToken = trim($tokens[$i]);

        if($currentToken == '(') {
            $jsonStr .= '{';
            continue;
        } elseif( $currentToken == ')') {
            $jsonStr = substr($jsonStr, 0, -2) . '}, ';
            continue;
        }

        if($nextToken == '(') {
            $jsonStr .= '"' . $currentToken . '": ';
        } else {
            $jsonStr .= '"' . $currentToken . '": "' . $currentToken . '", ';
        }
    }

    $jsonStr = substr($jsonStr, 0, -2) . '}';

    return json_decode($jsonStr, true);
}

var_dump(parse($str));