This was in a repo, but moving to a Gist and deleting the repo because it's no longer useful.

IDDescribeVar

<?php

/*
 * Outputs the type, length and contents of a variable in a readable format, which can be useful for debugging.
 * Output can be sent to echo(), die() / wp_die(), returned, a WordPress transient or a WordPress admin notice
 * (via the IDAdminNotice class, not included). There are extra output methods for use in a WordPress environment, 
 * but it will also work on it's own.
 */

/*  
 * Copyright 2011 Ian Dunn (email : ian@iandunn.name)
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as 
 * published by the Free Software Foundation.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

if( $_SERVER['SCRIPT_FILENAME'] == __FILE__ )
	die( 'Access denied.' );

if( !class_exists( 'IDDescribeVar' ) )
{
	/**
	 * @package IDDescribeVar
	 * @author Ian Dunn <ian@iandunn.name>
	 */
	class IDDescribeVar
	{
		// Declare variables and constants
		const NAME		= 'ID Describe Var';
		const VERSION	= '0.1';
		const PREFIX	= 'iddv_';
		
		/**
		 * Prints the input in various ways for debugging.
		 * @author Ian Dunn <ian@iandunn.name>
		 * @param mixed $data
		 * @param string $output 'message' will be sent to an IDAdminNotice; 'die' will be output inside wp_die() or die(); 'transient' will create a transient in the database (WordPress only); 'return' will be returned;
		 * @param string $message Optional message to output before description
		 * @return mixed
		 */
		public static function describe( $data, $output = 'die', $message = '' )
		{
			$type = gettype( $data );

			// Build description
			switch( $type )
			{
				case 'array':
				case 'object':
					$length = count( $data );
					$data = print_r( $data, true );
				break;
				
				case 'string';
					$length = strlen( $data );
				break;
				
				default:
					$length = count( $data );
					
					ob_start();
					var_dump( $data );
					$data = ob_get_contents();
					ob_end_clean();
					
					$data = print_r( $data, true );
				break;
			}
			
			$description = sprintf('
				<p>
					%s
					Type: %s<br />
					Length: %s<br />
					Content: <br /><blockquote><pre>%s</pre></blockquote>
				</p>',
				( $message ? 'Message: '. $message .'<br />' : '' ),
				$type,
				$length,
				htmlspecialchars( $data )
			);
			
			// Output description
			switch( $output )
			{
				case 'notice':
					if( class_exists( 'IDAdminNotices' ) )
						IDAdminNotices::cGetSingleton()->mEnqueue( $description, 'update' );	// @todo store a private var w/ the instance so you're not calling the singleton method multiple times when this function is called multiple times
					else
						throw new Exception( self::NAME .' error: IDAdminNotices class not available.' );
				break;
				
				case 'return':
					return $description;
				break;
				
				case 'transient':
					if( function_exists( 'set_transient' ) )
					{
						$uniqueKey = $message ? str_replace( array( ' ', '-', '/', '\\', '.' ), '_', $message ) : mt_rand();	// removes characters that are invalid in MySQL column names
						set_transient( self::PREFIX . 'describe_' . $uniqueKey, $description, 60 * 60 );
					}
					else
						throw new Exception( self::NAME ." error: WordPress' set_transient() function not available." );
				break;
				
				case 'echo':
					echo $description;		// @todo - want to esc_html on message, but not entire description. can't do to $message above because don't want to escape for other switch cases
				break;
				
				case 'die':
				default:
					if( function_exists( 'wp_die' ) )
						wp_die( $description );
					else
						die( $description );
				break;
			}
		}
	} // end IDDescribeVar
}

if( class_exists( 'IDAdminNotices' ) )
	IDAdminNotices::cGetSingleton();	// initialize the singleton instance as early as possible to make sure hook callbacks are registered in time
	
?>