docs: public final EObject ruleXWhileExpression() throws RecognitionException {
          EObject current = null;
  
          Token otherlv_1=null;
          Token otherlv_2=null;
          Token otherlv_4=null;
          EObject lv_predicate_3_0 = null;
  
          EObject lv_body_5_0 = null;
  
  
  
          	enterRule();
  
          try {
              // InternalSARL.g:14605:2: ( ( () otherlv_1= 'while' otherlv_2= '(' ( (lv_predicate_3_0= ruleXExpression ) ) otherlv_4= ')' ( (lv_body_5_0= ruleXExpression ) ) ) )
              // InternalSARL.g:14606:2: ( () otherlv_1= 'while' otherlv_2= '(' ( (lv_predicate_3_0= ruleXExpression ) ) otherlv_4= ')' ( (lv_body_5_0= ruleXExpression ) ) )
              {
              // InternalSARL.g:14606:2: ( () otherlv_1= 'while' otherlv_2= '(' ( (lv_predicate_3_0= ruleXExpression ) ) otherlv_4= ')' ( (lv_body_5_0= ruleXExpression ) ) )
              // InternalSARL.g:14607:3: () otherlv_1= 'while' otherlv_2= '(' ( (lv_predicate_3_0= ruleXExpression ) ) otherlv_4= ')' ( (lv_body_5_0= ruleXExpression ) )
              {
              // InternalSARL.g:14607:3: ()
              // InternalSARL.g:14608:4: 
              {
              if ( state.backtracking==0 ) {
  
                				current = forceCreateModelElement(
                					grammarAccess.getXWhileExpressionAccess().getXWhileExpressionAction_0(),
                					current);
                			
              }
  
              }
  
              otherlv_1=(Token)match(input,131,FOLLOW_80); if (state.failed) return current;
              if ( state.backtracking==0 ) {
  
                			newLeafNode(otherlv_1, grammarAccess.getXWhileExpressionAccess().getWhileKeyword_1());
                		
              }
              otherlv_2=(Token)match(input,49,FOLLOW_45); if (state.failed) return current;
              if ( state.backtracking==0 ) {
  
                			newLeafNode(otherlv_2, grammarAccess.getXWhileExpressionAccess().getLeftParenthesisKeyword_2());
                		
              }
              // InternalSARL.g:14622:3: ( (lv_predicate_3_0= ruleXExpression ) )
              // InternalSARL.g:14623:4: (lv_predicate_3_0= ruleXExpression )
              {
              // InternalSARL.g:14623:4: (lv_predicate_3_0= ruleXExpression )
              // InternalSARL.g:14624:5: lv_predicate_3_0= ruleXExpression
              {
              if ( state.backtracking==0 ) {
  
                					newCompositeNode(grammarAccess.getXWhileExpressionAccess().getPredicateXExpressionParserRuleCall_3_0());
                				
              }
              pushFollow(FOLLOW_81);
              lv_predicate_3_0=ruleXExpression();
  
              state._fsp--;
              if (state.failed) return current;
              if ( state.backtracking==0 ) {
  
                					if (current==null) {
                						current = createModelElementForParent(grammarAccess.getXWhileExpressionRule());
                					}
                					set(
                						current,
                						"predicate",
                						lv_predicate_3_0,
                						"org.eclipse.xtext.xbase.Xbase.XExpression");
                					afterParserOrEnumRuleCall();
                				
              }
  
              }
  
  
              }
  
              otherlv_4=(Token)match(input,50,FOLLOW_45); if (state.failed) return current;
              if ( state.backtracking==0 ) {
  
                			newLeafNode(otherlv_4, grammarAccess.getXWhileExpressionAccess().getRightParenthesisKeyword_4());
                		
              }
              // InternalSARL.g:14645:3: ( (lv_body_5_0= ruleXExpression ) )
              // InternalSARL.g:14646:4: (lv_body_5_0= ruleXExpression )
              {
              // InternalSARL.g:14646:4: (lv_body_5_0= ruleXExpression )
              // InternalSARL.g:14647:5: lv_body_5_0= ruleXExpression
              {
              if ( state.backtracking==0 ) {
  
                					newCompositeNode(grammarAccess.getXWhileExpressionAccess().getBodyXExpressionParserRuleCall_5_0());
                				
              }
              pushFollow(FOLLOW_2);
              lv_body_5_0=ruleXExpression();
  
              state._fsp--;
              if (state.failed) return current;
              if ( state.backtracking==0 ) {
  
                					if (current==null) {
                						current = createModelElementForParent(grammarAccess.getXWhileExpressionRule());
                					}
                					set(
                						current,
                						"body",
                						lv_body_5_0,
                						"org.eclipse.xtext.xbase.Xbase.XExpression");
                					afterParserOrEnumRuleCall();
                				
              }
  
              }
  
  
              }
  
  
              }
  
  
              }
  
              if ( state.backtracking==0 ) {
  
                	leaveRule();
  
              }
          }
  
              catch (RecognitionException re) {
                  recover(input,re);
                  appendSkippedTokens();
              }
          finally {
          }
          return current;
      }