package runEnv;

import env.*;
import type.*;

public class RunEnv {

/*
Represents the run time environment, composed of 
the globals, current instance, and current invocation.
*/
	private StaticValue currentStatic;
	private InstanceValue currentInstance;
	private InvocationValue currentInvocation;
	
	public StaticValue currentStatic() { return currentStatic; }
	public InstanceValue currentInstance() { return currentInstance; }
	public InvocationValue currentInvocation() { return currentInvocation; }
	
	public RunEnv( 
		StaticValue currentStatic,
		InstanceValue currentInstance,
		InvocationValue currentInvocation ) {
		this.currentStatic = currentStatic;
		this.currentInstance = currentInstance;
		this.currentInvocation = currentInvocation;
		}

	public RunData getData( Decl decl ) {
		switch ( decl.section() ) {
			case Decl.SECT_GLOBAL:
			case Decl.SECT_STATIC:
				return currentStatic.fields().getData( decl.offset() );
			case Decl.SECT_INSTANCE:
				return currentInstance.fields().getData( decl.offset() );
			case Decl.SECT_VARPARAM:
				return currentInvocation.locals().getValue( decl.offset() ).dataValue();
			case Decl.SECT_VALUEPARAM:
			case Decl.SECT_LOCAL:
				return currentInvocation.locals().getData( decl.offset() );
			default:
				throw new Error( "Invalid section in declaration of " + decl.section() );
			}
		}

	}