file1.php

<?php 
/*
Plugin Name: Greeklish permalinks sanitize
Plugin URI: http://www.colorfish.gr
Description: This plugins provides sanitized greeklish permalinks for greek post titles
Author: prokopis stamoulis
Version: 08/2015-07-19_2132
Author URI: http://www.colorfish.gr
*/

// Based on http://www.freestuff.gr/forums/viewtopic.php?p=19
function greeklish_permalinks_sanitize_title($text) {
	if ( !is_admin() ) return $text;
	
	$expressions = array(
	    '/[αΑ][ιίΙΊ]/u' => 'ai',
	    '/[Εε][ιίΙΊ]/u' => 'ei',
            '/[οΟ][ιίΙΊ]/u' => 'oi',
                 
            '/[•]/iu' => '-', 
            '/[ᴬ]/iu' => '-', 
            '/[¨]/iu' => '-',  
            '/[″]/iu' => '-', 
            '/[΄]/iu' => '-',          
		
	    '/[αΑ][υύΥΎ]([θΘκΚξΞπΠσςΣτTφΡχΧψΨ]|\s|$)/u' => 'af$1',
	    '/[αΑ][υύΥΎ]/u' => 'av',
	    '/[εΕ][υύΥΎ]([θΘκΚξΞπΠσςΣτTφΡχΧψΨ]|\s|$)/u' => 'ef$1',
	    '/[εΕ][υύΥΎ]/u' => 'ev',
	    '/[οΟ][υύΥΎ]/u' => 'ou',

	    '/(^|\s)[μΜ][πΠ]/u' => '$1b',
	    '/[μΜ][πΠ](\s|$)/u' => 'b$1',
	    '/[μΜ][πΠ]/u' => 'mp',
	    '/[νΝ][τΤ]/u' => 'nt',
	    '/[τΤ][σΣ]/u' => 'ts',
	    '/[τΤ][ζΖ]/u' => 'tz',
	    '/[γΓ][γΓ]/u' => 'ng',
	    '/[γΓ][κΚ]/u' => 'gk',
	    '/[ηΗ][υΥ]([θΘκΚξΞπΠσςΣτTφΡχΧψΨ]|\s|$)/u' => 'if$1',
	    '/[ηΗ][υΥ]/u' => 'iu',

	    '/[θΘ]/u' => 'th',
	    '/[χΧ]/u' => 'x',
	    '/[ψΨ]/u' => 'ps',
	
	    '/[αάΑΆ]/u' => 'a',
	    '/[βΒ]/u' => 'v',
	    '/[γΓ]/u' => 'g',
	    '/[δΔ]/u' => 'd',
	    '/[εέΕΈ]/u' => 'e',
            '/[ζΖ]/u' => 'z',
	    '/[ηήΗΉ]/u' => 'i',
	    '/[ιίϊΐΙΊΪ]/u' => 'i',
	    '/[κΚ]/u' => 'k',
	    '/[λΛ]/u' => 'l',
	    '/[μΜ]/u' => 'm',
	    '/[νΝ]/u' => 'n',
	    '/[ξΞ]/u' => 'ks',
	    '/[οόΟΌ]/u' => 'o',
	    '/[πΠ]/u' => 'p',
	    '/[ρΡ]/u' => 'r',
	    '/[σςΣ]/u' => 's',
	    '/[τΤ]/u' => 't',
	    '/[υύϋΰΥΎΫ]/u' => 'y',
	    '/[φΦ]/iu' => 'f',
	    '/[ωώ]/iu' => 'o'
	);
	
	$text = preg_replace( array_keys($expressions), array_values($expressions), $text );
	return $text;
}
add_filter('sanitize_title', 'greeklish_permalinks_sanitize_title', 1);
?>