initial commit of validation classes.

system/validation/rules/format_of.php

@@ -0,0 +1,43 @@
+<?php namespace System\Validation\Rules;
+
+use System\Validation\Rule;
+
+class Format_Of extends Rule {
+
+	/**
+	 * The regular expression that will be used to evaluate the attribute.
+	 *
+	 * @var string
+	 */
+	public $expression;
+
+	/**
+	 * Evaluate the validity of an attribute.
+	 *
+	 * @param  string  $attribute
+	 * @param  array   $attributes
+	 * @return void
+	 */
+	public function check($attribute, $attributes)
+	{
+		if ( ! array_key_exists($attribute, $attributes))
+		{
+			return true;
+		}
+
+		return preg_match($this->expression, $attributes[$attribute]);
+	}	
+
+	/**
+	 * Set the regular expression.
+	 *
+	 * @param  string  $expression
+	 * @return Format_Of
+	 */
+	public function with($expression)
+	{
+		$this->expression = $expression;
+		return $this;
+	}
+
+}