onOverride

OnOverride.cyan

package metaobjectTest


@doc{*
    Annotations of this metaobject are attached to a declaration. The
    Cyan code attached to the annotation is run in phase afterSemAn. Method 
    afterSemAn_checkOverride of the class of metaobject onOverride,
    overridden from ICheckOverride_afterSemAn, just interpret the Cyan 
    statements attached to the annotation. 
    
    Then, in phase afterSemAn of the compilation, the Myan statements 
    attached to the annotation onOverride below are interpreted. 
    Myan is interpreted Cyan.
    
    To better understand this, see the documentation for action_afterResTypes_semAn.
*}
open
object OnOverride

    func run {
    }
    
    @onOverride{*
        // the overridden method should call 
        // this method in its first statement
        // shouldCallSuperMethod is an action function
        // of package cyan.lang
        call: #shouldCallSuperMethod;
    *}
    /*  print a warning message if method 'draw' is overridden in 
        a subprototype that does not declares a 'subMethod' method.
    */
    @onOverride{*
        var Boolean found = false;
        var methodList = 
            method getDeclaringObject getMethodDecList: (compiler getEnv);
        for i in 0..< methodList size {
            var String methodName = (methodList get: i) getName;
            if methodName == "subMethod" {
                found = true;
                break;
            }
        }
        if !found  {
            var String protoName = method getDeclaringObject getName;
            Out println: "Prototype " ++ method getDeclaringObject getName ++ 
               " should have a 'subMethod' method";
        }

    *}
    func draw {
    }

        
end