Greetings! On Wed, 2010-07-07 at 22:24 +0100, Matt Palmer wrote: ...snipped.... > > chars : CHAR+ -> ^(CONCAT CHAR+) ; > ...snipped... chars : (CHAR->CHAR) ( chars -> ^(CONCAT CHAR chars) )? ; but the above tree will be right associative. is that a problem for you? hope this helps -jbb