org.snapscript.tree.construct.MapKey Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of snap Show documentation

Dynamic scripting for the JVM

The newest version!

package org.snapscript.tree.construct;

import java.util.concurrent.atomic.AtomicReference;

import org.snapscript.core.Evaluation;
import org.snapscript.core.scope.Scope;
import org.snapscript.core.scope.ScopeState;
import org.snapscript.core.scope.index.Address;
import org.snapscript.core.scope.index.ScopeIndex;
import org.snapscript.core.scope.index.ScopeTable;
import org.snapscript.core.variable.Value;
import org.snapscript.tree.NameReference;

public class MapKey extends Evaluation {
   
   private final AtomicReference location;
   private final NameReference reference;
   
   public MapKey(Evaluation key) {
      this.location = new AtomicReference();
      this.reference = new NameReference(key);
   }
   
   @Override
   public void define(Scope scope) throws Exception{
      String name = reference.getName(scope);
      ScopeIndex index = scope.getIndex();
      Address address = index.get(name);

      location.set(address);
   }
   
   @Override
   public Value evaluate(Scope scope, Value left) throws Exception{
      String name = reference.getName(scope);
      Address address = location.get();
      
      if(address == null){
         ScopeState state = scope.getState(); 
         Value value = state.getValue(name);
         
         if(value != null) { 
            return value;
         }
      }else {
         ScopeTable table = scope.getTable(); // here we use the stack
         Value value = table.getValue(address);
         
         if(value != null) { 
            return value;
         }
      }
      return Value.getTransient(name);
   }
}