code: /**
   * Copyright (c) 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.
   *
   * Created Sep 21, 2005
   */
  package jintgen.isdl;
  
  import jintgen.jigir.Decl;
  import jintgen.types.Type;
  import java.util.HashMap;
  
  /**
   * @author Ben L. Titzer
   */
  public class Environment {
  
      protected final Environment parent;
      protected final HashMap<String, Decl> varMap;
      protected final HashMap<String, SubroutineDecl> methodMap;
  
      public Environment(Environment p) {
          parent = p;
          varMap = new HashMap<String, Decl>();
          methodMap = new HashMap<String, SubroutineDecl>();
      }
  
      public Decl resolveDecl(String name) {
          Decl decl = varMap.get(name);
          if ( decl != null ) return decl;
          return parent != null ? parent.resolveDecl(name) : null;
      }
  
      public SubroutineDecl resolveSubroutine(String name) {
          SubroutineDecl type = methodMap.get(name);
          if ( type != null ) return type;
          return parent != null ? parent.resolveSubroutine(name) : null;
      }
  
      public void addDecl(Decl d) {
          varMap.put(d.getName(), d);
      }
  
      public void addVariable(String name, Type t) {
          varMap.put(name, new VarDecl(name, t));
      }
  
      public void addSubroutine(SubroutineDecl d) {
          methodMap.put(d.name.image, d);
      }
  
      public boolean isDefinedLocally(String name) {
          return varMap.containsKey(name);
      }
  
      public Iterable<Decl> getDecls() {
          return varMap.values();
      }
  
      protected class VarDecl implements Decl {
          protected final String name;
          protected final Type type;
  
          protected VarDecl(String n, Type t) {
              name = n;
              type = t;
          }
  
          public String getName() {
              return name;
          }
  
          public Type getType() {
              return type;
          }
      }
  }
  