<?php

class validator {
	function __construct($scheme, $isFile) {
		$this->errors = null;
		if ($isFile) {
			$this->scheme = simplexml_load_file($scheme);
		}
		else {
			$this->scheme = simplexml_load_string($scheme);
		}
		// foreach validation section
		foreach($this->scheme as $name => $node) {
			if ((string) $name != 'errors') {
				$validator = (string) $name['validator'];
				// foreach field
				foreach($node->fields as $field) {
					$requestObject = $this->getReference($field['type']);
					eval("$validator::check({$field['id']}, {&$requestObject}))");
				}
				echo (string)  . '<br>';
			}
		}
		die();
		$this->prepareErrorArray();
	}
	private function addError($field, $name, $error, $otherData = null) {
		$error = str_replace('*field*', (string) $name, (string) $error);
		if (is_array($otherData)) {
			foreach($otherData as $key => $data) {
				$error = str_replace("*$key*", $data, $error);
			}
		}
		$this->errors[(string) $field] = $error;
	}
	private function prepareErrorArray() {
		var_dump($this->errors);
	}
	private function getReference($type) {
		switch($type) {
			case 'get':
				return $_GET;
				break;
			case 'post':
				return $_POST;
				break;
			case 'cookie':
				return $_COOKIE;
			case 'file':
				return $_FILES;
			default:
				throw new Exception('Bad variable type');
		}
	}
}

class checkNumeracy extends validator {
	static function check($value) {
		if (is_numeric($value, $requestObject)) {
			return true;
		}
		else {
			return true;
		}
	}
}

class checkPresence extends validator {
	static function check($value, $requestObject) {
		return isset($requestObject[(string) $value]);
	}
}

$scheme = file_get_contents('valid.xml');
$v = new validator($scheme, false);