在xtext中自定义代码折叠

Question

在我目前的项目中，我试图在编辑器中提供代码折叠支持，从xtext语法生成。感谢xtext，当我有两行时，它提供了非常好的代码折叠支持。但是，当它只包含一行时，我无法折叠代码（为清楚起见，我附加了为此规范编写的图像文件和语法）。当一个块有三行时折叠代码是默认行为吗？如何更改默认行为？

该规范的语法如下：

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"

Model:
    (vocSpec=VocSpec);

VocSpec:
    'structs:' (structs+=Struct)+
    'resources:'   
    'sensors:' 
    'periodicSensors:' (periodicSensors+=PeriodicSensors)*
    'eventDrivenSensors:' (eventSensors+=EventSensors)*
    'requestBasedSensors:' (requestSensors+=RequestSensors)*
    'tags:' (tags+=Tags)*
    'actuators:' (actuators+=Actuator)*
    'storages:' (storageService+=StorageService)* 
    ;

Struct:
    name=StructEntityName (fields+=Field)+;

Field:
    name=ID ':' type+=Type ';' 
;

/* Periodic Sensor Definition */
PeriodicSensors:
    sensorName=EntityName
    (generateInfo+=Generate)+
    sampelingDef= SampelingDef
;

SampelingDef:
    'sample' 'period' INT 'for' INT ';'
;

/* Event Driven Sensor Definition */
EventSensors:
    sensorName=EntityName
    (generateInfo+=Generate)+
    onConditionDef= OnConditionDef ;

OnConditionDef:
    'onCondition' (eventConditions+=EventConditions) ';'
;

/* Request Based Sensor Definition */
RequestSensors:
    sensorName=EntityName
    (dataAccess+=DataAccessForRequestSensors)+ 
;


/* Tag Definition */
Tags:
    sensorName=EntityName
    (generateInfo+=Generate)+
    ;

    EventConditions:
    name=ID ('>' | '<' | '=')* (intValue=INT) (nameUnit=Unit) (',' eventConditions+=EventConditions)?


OPERATOR:
    opt='>' | opt='<' | opt='=';

DeviceEntityName:
    (name=ID);

StructEntityName:
    (name=ID);

EntityName:
    (name=ID);

    //EntityName:  (name = ID | name = 'EndUserApp' | name = 'DashBoard')  ;
Generate:
    'generate' sourceName=SourceName ':' type=Type ';';

SourceName:
    name=ID;

/* Actuator Definition */
Actuator:
    actuatorName=EntityName
    (actions += Action)*
    ;

Action:
    'action' actionName=ActionName '(' (parameters+=Parameters)* ')' ';';

ActionName:
    name=ID;

Parameters:
    parameterName=ParameterName ':' type=Type;

ParameterName:
    name=ID;

/*  Storage Service Definition  */
StorageService:
    storageServiceName=EntityName
    ((dataAccesses+=DataAccess))*;

DataAccessForRequestSensors:
    'generate' sourceName=SourceName ':' dataAccessType=Type
    'accessed-by' dataItem=ID ':' type=Type ';'
;


DataAccess:
    'generate' sourceName=SourceName ':' dataAccessType=Type
    'accessed-by' dataItem=ID ':' type=Type ';'
    ((actions+=Action))*;

/* Type Definition */
Type:
    (primitiveDataType=PrimitiveDataType);

Unit:
    name='PPM' | name='miliseconds' | name='seconds' | name='minutes' | name='ppm';

OperationName:
    name='AVG_BY_SAMPLE';

PrimitiveDataType:
    INTEGER='Integer' | BOOLEAN='boolean' | STRING='String' | LONG='long' | DOUBLE='double' | structDef=[StructEntityName];