code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  
  package org.apache.xalan.xsltc.compiler;
  
  import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
  import org.apache.xalan.xsltc.compiler.util.ErrorMsg;
  import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
  import org.apache.xalan.xsltc.compiler.util.Type;
  import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
  
  /**
   * @author Morten Jorgensen
   */
  final class UnresolvedRef extends VariableRefBase {
  
      private QName _variableName = null;
      private VariableRefBase _ref = null;
  
      public UnresolvedRef(QName name) {
  	super();
  	_variableName = name;
      }
  
      public QName getName() {
  	return(_variableName);
      }
  
      private ErrorMsg reportError() {
  	ErrorMsg err = new ErrorMsg(ErrorMsg.VARIABLE_UNDEF_ERR,
  				    _variableName, this);
  	getParser().reportError(Constants.ERROR, err);
  	return(err);
      }
  
      private VariableRefBase resolve(Parser parser, SymbolTable stable) {
  	// At this point the AST is already built and we should be able to
  	// find any declared global variable or parameter
  	VariableBase ref = parser.lookupVariable(_variableName);
  	if (ref == null) {
              ref = (VariableBase)stable.lookupName(_variableName);
          }
  	if (ref == null) {
  	    reportError();
  	    return null;
  	}
  	
          // If in a top-level element, create dependency to the referenced var
          _variable = ref;
          addParentDependency();
          
  	if (ref instanceof Variable) {
  	    return new VariableRef((Variable) ref);
          }
  	else if (ref instanceof Param) {
  	    return new ParameterRef((Param)ref);
          }        
          return null;
      }
  
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
  	if (_ref != null) {
  	    final String name = _variableName.toString();
  	    ErrorMsg err = new ErrorMsg(ErrorMsg.CIRCULAR_VARIABLE_ERR,
  					name, this);
  	}
  	if ((_ref = resolve(getParser(), stable)) != null) {
  	    return (_type = _ref.typeCheck(stable));
  	}
  	throw new TypeCheckError(reportError());
      }
  
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
  	if (_ref != null)
  	    _ref.translate(classGen, methodGen);
  	else
  	    reportError();
      }
  
      public String toString() {
  	return "unresolved-ref()";
      }
  
  }
  