收集公园的递归方法

问题描述

我正在使用 Xtext 编写语法，并且正在自定义范围提供程序，因为我想实现以下示例。我在代码中写了一些注释以帮助更好地理解。

country C1 {
    forest F1 {
        park P1 {
            enter EN1
            exit EX1
            park P2 {
                enter EN2
                exit EX2
                park P3 
                park P4 {
                    enter EN3 
                    exit EX3
                    park P5
                    workingarea W4 from EN1 to P2 //need to have from: P5,P4.EN3 to: P5,P4.EX3 because P4 only contains P4.EN3,P4.EX3 and P5
                }
             workingarea W2 from EN1 to P2 //need to have from: P2.EN2,P3,P4,P4.EN3  to: P2.EX2,P4.EX3 because P2 contains P2.EN2,P2.EX2,P4.EN3 and P4.EX3. Contrary to others,here we have two parks contained in one park therefore we also allow P3 and P4,not only P4.EN3 and P4.EX3
            }
         workingarea W1 from EN1 to P2 //need to have from: P1.EN1  to:  P1.EX1     
        }
        park P6 {
            enter EN4 
            exit EX4
            }
        workingarea WF from EN4 to P6 // From: P1,P6,P1.EN1,P6.EN4. To should be: P1.EX1,P6.EX4,P1,P6
    }
}

所以总结属于一个公园的每个工作区域，应该允许交叉引用同一个公园的入口和出口，该公园的子公园及其对应的入口和出口。

我想使用递归方法来实现我刚才提到的内容，我尝试自定义范围提供程序以提供该功能，但没有成功。这是仅用于 from 的范围提供程序，因为 to 将遵循相同的逻辑：

public class ForestScopeProvider extends AbstractForestScopeProvider {
    @Override
    public IScope getScope(EObject context,EReference reference) {
        
       if (reference == ForestPackage.Literals.WORKING_AREA__FROM) {
            Country rootCountry = (Country) EcoreUtil2.getRootContainer(context);
            List<EObject> workingarea = new ArrayList<>();
            while (rootCountry != null) {
            for (Park park :rootCountry.getForests().getParks()) 
                {
                while (park !=null) {
                    workingarea.addAll(park.getParks()); 
                    workingarea.addAll(park.getEnter());
                    park = (Park) park.getParks();
                }   
            }
                rootCountry = rootCountry.getSupercountry();
            
           System.out.println(workingarea);
            return Scopes.scopeFor(workingarea);
        }
      }
}
}

这是Xtext中的语法

Country:
    "country" name=ID ("extends" supercountry=[Country|Qualifiedname])? "{"
    forests=Forest
    "}"
    ;
Forest: 
    "forest" name=ID "{"
    ("park" parks+=Park ("," parks+=Park)*)*
    ("workingarea"  workingarea=WorkingArea)*
    "}";
    
Park:
     name=ID ("{"
    "enter" enter+=Enter
    "exit" exit+=Exit
    ("park" parks+=Park ("," parks+=Park)*)*
    ("workingarea"  workingarea=WorkingArea)*
    "}")*
;
WorkingArea:
    name=ID "from" from=[ParkEnter] "to" to=[ParkExit] 
;

Enter:
    name=ID
;
Exit:
    Name=ID
;
ParkEnter:
    Park | Enter
;
ParkExit:
    Park | Exit
;

Qualifiedname:
 ID ('.' ID)*
 ;

解决方法

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