org.snapscript.core.scope.index.StackIndex Maven / Gradle / Ivy
package org.snapscript.core.scope.index;
import java.util.Iterator;
import org.snapscript.common.ArrayStack;
import org.snapscript.common.Cache;
import org.snapscript.common.HashCache;
import org.snapscript.common.Stack;
public class StackIndex implements Index {
private final Cache locals;
private final Stack stack;
public StackIndex() {
this.locals = new HashCache();
this.stack = new ArrayStack(0); // do not use default
}
@Override
public Iterator iterator(){
return locals.keySet().iterator();
}
@Override
public int get(String name) {
Integer index = locals.fetch(name);
if(index != null){
return index;
}
return -1;
}
@Override
public int index(String name) {
Integer index = locals.fetch(name);
if(index != null) {
throw new IllegalStateException("Duplicate variable '" + name + "' in scope");
}
int size = locals.size();
locals.cache(name, size);
stack.push(name);
return size;
}
@Override
public void reset(int index) {
int size = locals.size();
for(int i = size; i > index; i--) {
String name = stack.pop();
locals.take(name);
}
}
@Override
public int size(){
return locals.size();
}
@Override
public String toString() {
return String.valueOf(locals);
}
}