docs: public final AntlrDatatypeRuleToken ruleFeatureCallID() throws RecognitionException {
          AntlrDatatypeRuleToken current = new AntlrDatatypeRuleToken();
  
          Token kw=null;
          AntlrDatatypeRuleToken this_InnerVarID_0 = null;
  
  
  
          	enterRule();
  
          try {
              // InternalSARL.g:9886:2: ( (this_InnerVarID_0= ruleInnerVarID | kw= 'extension' ) )
              // InternalSARL.g:9887:2: (this_InnerVarID_0= ruleInnerVarID | kw= 'extension' )
              {
              // InternalSARL.g:9887:2: (this_InnerVarID_0= ruleInnerVarID | kw= 'extension' )
              int alt256=2;
              int LA256_0 = input.LA(1);
  
              if ( (LA256_0==RULE_ID||LA256_0==25||LA256_0==28||LA256_0==36||LA256_0==39||(LA256_0>=42 && LA256_0<=44)||LA256_0==51||(LA256_0>=78 && LA256_0<=96)) ) {
                  alt256=1;
              }
              else if ( (LA256_0==45) ) {
                  alt256=2;
              }
              else {
                  if (state.backtracking>0) {state.failed=true; return current;}
                  NoViableAltException nvae =
                      new NoViableAltException("", 256, 0, input);
  
                  throw nvae;
              }
              switch (alt256) {
                  case 1 :
                      // InternalSARL.g:9888:3: this_InnerVarID_0= ruleInnerVarID
                      {
                      if ( state.backtracking==0 ) {
  
                        			newCompositeNode(grammarAccess.getFeatureCallIDAccess().getInnerVarIDParserRuleCall_0());
                        		
                      }
                      pushFollow(FOLLOW_2);
                      this_InnerVarID_0=ruleInnerVarID();
  
                      state._fsp--;
                      if (state.failed) return current;
                      if ( state.backtracking==0 ) {
  
                        			current.merge(this_InnerVarID_0);
                        		
                      }
                      if ( state.backtracking==0 ) {
  
                        			afterParserOrEnumRuleCall();
                        		
                      }
  
                      }
                      break;
                  case 2 :
                      // InternalSARL.g:9899:3: kw= 'extension'
                      {
                      kw=(Token)match(input,45,FOLLOW_2); if (state.failed) return current;
                      if ( state.backtracking==0 ) {
  
                        			current.merge(kw);
                        			newLeafNode(kw, grammarAccess.getFeatureCallIDAccess().getExtensionKeyword_1());
                        		
                      }
  
                      }
                      break;
  
              }
  
  
              }
  
              if ( state.backtracking==0 ) {
  
                	leaveRule();
  
              }
          }
  
              catch (RecognitionException re) {
                  recover(input,re);
                  appendSkippedTokens();
              }
          finally {
          }
          return current;
      }