(: tools to analyse xml parse tree
@author Andy Bunce
:)
module namespace hnd="lsp/handlers";


(:~ structure returned by tree walkers :)
declare record hnd:Result( 
    result as item()*,
    skipchildren? as xs:boolean:=false() 
);

declare type hnd:actionFn as fn($parse  as element(),$state as hnd:Result  ) as hnd:Result;

declare type hnd:actionMap as  map(xs:string,hnd:actionFn);

declare function hnd:walk($parse as element(), 
                         $actions as hnd:actionMap, 
                         $state as hnd:Result )
as hnd:Result
{
  let $action:=$actions(name($parse))
  let $result:= if(exists($action))
                then $action($parse,$state)
                else hnd:Result($state)
 
  return if($result?skipchildren)
         then $result
         else fold-left(
                $parse/*,$state,
                fn($state,$this){hnd:walk($this, $actions, $state)}
                     )
};