code: /**
   * Copyright (c) 2004-2005, Regents of the University of California
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * Neither the name of the University of California, Los Angeles nor the
   * names of its contributors may be used to endorse or promote products
   * derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package avrora.syntax;
  
  import avrora.arch.legacy.LegacyRegister;
  import cck.parser.AbstractToken;
  
  /**
   * The <code>Context</code> interface represents a context in which an expression in a program should be
   * evaluated. It provides the environmental bindings necessary to resolve variable references within computed
   * expressions.
   *
   * @author Ben L. Titzer
   */
  public interface Context {
  
      /**
       * The <code>getRegister()</code> method resolves a register that may have been renamed earlier in the
       * program.
       *
       * @param ident the string name of the register or register alias
       * @return a reference to the <code>LegacyRegister</code> instance representing the register with the
       *         specified name or alias
       */
      public LegacyRegister getRegister(AbstractToken ident);
  
      /**
       * The <code>getVariable()</code> method looks up the value of a named constant within the current
       * environment and returns its value.
       *
       * @param ident the name of the variable
       * @return the value of the variable within the environment
       */
      public int getVariable(AbstractToken ident);
  }
  