import java.util.*;
public class Block implements Scope{
private Map locals = new HashMap();
private Map initializedVariables = new HashMap();
private Scope enclosingScope;
private String scopeName = "local";
public Block(Scope enclosingScope){
this.enclosingScope = enclosingScope;
}
@Override public String getScopeName(){
return scopeName;
}
/** Where to look next for symbols; */
@Override public Scope getEnclosingScope(){
return enclosingScope;
}
/** Define a symbol in the current scope */
@Override public void define(Symbol sym){
locals.put(sym.getName(), sym);
}
@Override public void initialize(Symbol sym){
initializedVariables.put(sym.getName(), sym);
}
@Override public Symbol lookup(String name){
if(locals.containsKey(name)){
return locals.get(name);
}else{
return this.getEnclosingScope().lookup(name);
}
}
@Override public Symbol lookupLocally(String name){
return locals.get(name);
}
@Override public boolean hasBeenInitialized(String name){
if(initializedVariables.containsKey(name)){
return true;
}else{
return this.getEnclosingScope().hasBeenInitialized(name);
}
}
@Override public Set getInitializedVariables(){
return new HashSet(this.initializedVariables.values());
}
}