[feuervogel]

prinzipiell so:

function latex( $string ) {
		
		//wenn $string leer, retourniere falsch
		if ( empty( $string ) )
			return false;
			
		$nlsearch 	= array( "rn" , "r" );
		$nlreplace	= "n";
		$string		= str_replace( $nlsearch , $nlreplace , $string );
		
		//escape special chars
		$tobeescaped	= array( "\" , """ , "$" , "&" , "%" , "#" , "_" , "{" , "}" , "^" , "~" , "<" , ">");
		//replace:
		$escaped 		= array( "verb==" , ""'" , "$" , "&" , "%" , "#" , "_" , "{" , "}" , "verb=^=" , "verb=~=" , "verb=<=" , "verb=>=");
		//escape 'em
		$string			= str_replace( $tobeescaped , $escaped , $string );

		//array with all strings wich have to be replaced
		//frage: was gibts außer t noch für seitenvorschubssequenzen?
		$tobereplaced	= array( "ä" , "ö" , "ü" , "Ä" , "Ö" , "Ü" , "ß" );
		//array with their replacements
		$replacements	= array( ""a" , ""o" , ""u" , ""A" , ""O" , ""U" ); 
		//replace 'em
		$string 		= str_replace( $tobereplaced , $replacements , $string );

		//simple text formats
		$tagspattern	= array( "%(.*)%Ui" , "%(.*)%Ui" , "%(.*)%Ui" );
		//their replacements
		$tagsrepl		= array( " 	extit{ $1 } " , " 	extbf{ $1 } " , " uline{ $1 } " );
		//replace 'em
		$string			= preg_replace( $tagspattern , $tagsrepl , $string );

		//return it
		return $string;
	
	}

ist aber noch betastatus weil noch nicht wirklich getestet...

es gehen halt schon simple sachen wie

[b] bold
[i] italic
[u] underline