validate_comparison.php

	/**
	 * Evaluates current object property by means of a comparison operator (< > == etc.) against a provided value.
	 *
	 * @param string $strKey Property name
	 * @param string $strComparisonOperator A comparison operator, < > == etc.
	 * @param string $strComparisonValue The value to compare with
	 * @param string $strErrorMessage (optional) a meaningful error message
	 * @return boolean
	 */
	function validate_comparison($strKey,$strComparisonOperator,$strComparisonValue,$strErrorMessage=null){
		if(!$this->$strKey){
			$this->add_error($strKey,'This object does not have a property named ' . $strKey);
			return false;
		}
		if(empty($strComparisonOperator) || empty($strComparisonValue)){
			$this->add_error($strKey,'Could not evaluate ' . $strKey . '! No comparison possible.');
			return false;
		}
		if(empty($strErrorMessage)) $strErrorMessage = $strKey . ' is not ' . $strComparisonOperator . ' ' . $strComparisonValue;
		if($this->$strKey . $strComparisonOperator . $strComparisonValue){
			return true;
		}else{
			$this->add_error($strKey,$strErrorMessage);
			return false;
		}
	}