<?php
namespace MadLisp;

class Util
{
    public static function makeHash(array $args): Hash
    {
        if (count($args) % 2 == 1) {
            throw new MadLispException('uneven number of arguments for hash');
        }

        $data = [];

        for ($i = 0; $i < count($args) - 1; $i += 2) {
            $key = $args[$i];
            $val = $args[$i + 1];

            if (!is_string($key)) {
                throw new MadLispException('invalid key for hash (not string)');
            }

            $data[$key] = $val;
        }

        return new Hash($data);
    }

    public static function valueForCompare($a)
    {
        if ($a instanceof Symbol) {
            return $a->getName();
        } elseif ($a instanceof Collection) {
            return $a->getData();
        }

        return $a;
    }
}