java - Xtext 没有从我的 dsl 生成完整的类

Question

我有一个 xtext 语法，我计划在应用程序中使用它。但是，当我检查生成的类时，某些项目丢失了。

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:
    model += ModelBlock+
;
ModelBlock:
    SystemBlock | DataSetBlock | RelationshipBlock
;
SystemBlock:
    'Systems' systemGroup=ID
    systems+=System+
;
DataSetBlock:
    'DataSets' datasetGroup=ID
    datasets+=DataSet+
    ;
RelationshipBlock:
    'Relationships' relationshipGroup=ID
    relationships+=Relationship+
;   
System:
    name = ID ':'
        'name:' nm = STRING
        ('description:' description = STRING)?
;
DataSet:
    name = ID ':'
        'name:' nm = STRING
;
Function:
    name = ID ':'
    'name:' nm = STRING
;
Relationship:
    SystemCONNECTSSystem |
    SystemCONSUMESDataSet | 
    SystemPRODUCESDataSet
;
SystemCONNECTSSystem:
    rel=ID 
        ':' lhs = [System] 
        'CONNECTS' rhs = [System] 
;
SystemCONSUMESDataSet:
    rel=ID ':' lhs = [System] 'CONSUMES' rhs = [DataSet] 
    ('WITH' 'frequency:' frequency = INT)?
;           
SystemPRODUCESDataSet:
    rel=ID ':' lhs = [System] 'PRODUCES' rhs = [DataSet] 
    ('WITH' 'frequency:' frequency = INT 
        ('risk:' risk = RiskEnum)?
    )?
;           
enum RiskEnum:
    h="high" | m="med" | l="low"
;

您会注意到类 SystemCONNECTSSystem、SystemPRODUCESDataSet 和 SystemCONSUMESDataSet 不生成属性 lhs，而是生成属性 rhs。参见下面的SystemPRODCUESDataSet，其他人也有同样的问题。

/**
 */
package org.xtext.example.mydsl.myDsl;


/**
 * <!-- begin-user-doc -->
 * A representation of the model object '<em><b>System PRODUCES Data Set</b></em>'.
 * <!-- end-user-doc -->
 *
 * <p>
 * The following features are supported:
 * </p>
 * <ul>
 *   <li>{@link org.xtext.example.mydsl.myDsl.SystemPRODUCESDataSet#getRhs <em>Rhs</em>}</li>
 *   <li>{@link org.xtext.example.mydsl.myDsl.SystemPRODUCESDataSet#getFrequency <em>Frequency</em>}</li>
 *   <li>{@link org.xtext.example.mydsl.myDsl.SystemPRODUCESDataSet#getRisk <em>Risk</em>}</li>
 * </ul>
 *
 * @see org.xtext.example.mydsl.myDsl.MyDslPackage#getSystemPRODUCESDataSet()
 * @model
 * @generated
 */
public interface SystemPRODUCESDataSet extends Relationship
{
  /**
   * Returns the value of the '<em><b>Rhs</b></em>' reference.
   * <!-- begin-user-doc -->
   * <p>
   * If the meaning of the '<em>Rhs</em>' reference isn't clear,
   * there really should be more of a description here...
   * </p>
   * <!-- end-user-doc -->
   * @return the value of the '<em>Rhs</em>' reference.
   * @see #setRhs(DataSet)
   * @see org.xtext.example.mydsl.myDsl.MyDslPackage#getSystemPRODUCESDataSet_Rhs()
   * @model
   * @generated
   */
  DataSet getRhs();

  /**
   * Sets the value of the '{@link org.xtext.example.mydsl.myDsl.SystemPRODUCESDataSet#getRhs <em>Rhs</em>}' reference.
   * <!-- begin-user-doc -->
   * <!-- end-user-doc -->
   * @param value the new value of the '<em>Rhs</em>' reference.
   * @see #getRhs()
   * @generated
   */
  void setRhs(DataSet value);

  /**
   * Returns the value of the '<em><b>Frequency</b></em>' attribute.
   * <!-- begin-user-doc -->
   * <p>
   * If the meaning of the '<em>Frequency</em>' attribute isn't clear,
   * there really should be more of a description here...
   * </p>
   * <!-- end-user-doc -->
   * @return the value of the '<em>Frequency</em>' attribute.
   * @see #setFrequency(int)
   * @see org.xtext.example.mydsl.myDsl.MyDslPackage#getSystemPRODUCESDataSet_Frequency()
   * @model
   * @generated
   */
  int getFrequency();

  /**
   * Sets the value of the '{@link org.xtext.example.mydsl.myDsl.SystemPRODUCESDataSet#getFrequency <em>Frequency</em>}' attribute.
   * <!-- begin-user-doc -->
   * <!-- end-user-doc -->
   * @param value the new value of the '<em>Frequency</em>' attribute.
   * @see #getFrequency()
   * @generated
   */
  void setFrequency(int value);

  /**
   * Returns the value of the '<em><b>Risk</b></em>' attribute.
   * The literals are from the enumeration {@link org.xtext.example.mydsl.myDsl.RiskEnum}.
   * <!-- begin-user-doc -->
   * <p>
   * If the meaning of the '<em>Risk</em>' attribute isn't clear,
   * there really should be more of a description here...
   * </p>
   * <!-- end-user-doc -->
   * @return the value of the '<em>Risk</em>' attribute.
   * @see org.xtext.example.mydsl.myDsl.RiskEnum
   * @see #setRisk(RiskEnum)
   * @see org.xtext.example.mydsl.myDsl.MyDslPackage#getSystemPRODUCESDataSet_Risk()
   * @model
   * @generated
   */
  RiskEnum getRisk();

  /**
   * Sets the value of the '{@link org.xtext.example.mydsl.myDsl.SystemPRODUCESDataSet#getRisk <em>Risk</em>}' attribute.
   * <!-- begin-user-doc -->
   * <!-- end-user-doc -->
   * @param value the new value of the '<em>Risk</em>' attribute.
   * @see org.xtext.example.mydsl.myDsl.RiskEnum
   * @see #getRisk()
   * @generated
   */
  void setRisk(RiskEnum value);

} // SystemPRODUCESDataSet

有人能解释一下这里发生了什么吗？

Answer 1

属性LHS在SystemPRODUCESDataSet及其 friend 的父类(super class)型上可用。 Relationship 应该为其公开一个 getter。这是因为 Relationship 的所有子类型都具有共同的 LHS，因此它会自动拉入父类(super class)型。