package node.exprNode.methodNameNode;
import node.*;
import node.declNode.*;
import node.exprNode.*;
import env.*;
import type.*;
import type.basicType.*;
import runEnv.*;
import code.*;
import text.*;

public class IdentMethodNameNode extends MethodNameNode {

	private String ident;
	
	public IdentMethodNameNode( String ident ) {
		this.ident = ident;
		}

	public String toString() {
		return ident;
		}

	public Type checkType() {
		decl = env().searchEnv( ident );
		if ( decl == null )
			throw new Error( "Undeclared method " + ident );
		switch ( decl.section() ) {
			case Decl.DECL_METHOD:
				type = ( MethodType ) decl.type();
				return type;
			default:
				throw new Error( ident + " must be a method" );
			}
		}

	public ObjectMethodPair eval( RunEnv runEnv ) {
		// Return an ObjectMethodPair representing 
		// the instance and code for the method
		switch ( decl.env().envKind() ) {
			case Env.ENV_CLASS:
				{
				PtrValue instanceValue = runEnv.instance();
				DeclList methodTable = 
					instanceValue.getValue().methodTable();
				return new ObjectMethodPair( instanceValue,
					methodTable.elementAt( decl.offset().interp() ) );
				}
			case Env.ENV_GLOBAL:
				{
				return new ObjectMethodPair( null, decl );
				}
			default:
				throw new Error( 
					"Invalid section of " + Decl.sectionText( decl.section() ) );
			}
		}

	public Register saveReg( int dataType, Usage usage ) {
		return null;
		}
		
	public void evalCode( Node sibling ) {
		setSibling( sibling );
		// Loads $nip and $pv with appropriate values.
		switch ( decl.env().envKind() ) {
			case Env.ENV_CLASS:
				Code.move( SpecialReg.instPtr, SpecialReg.newInstPtr );
				Code.load( IntType.type, SpecialReg.assemTemp, 
					new Displacement( 
						decl.env().absoluteName() + ".field.methodTablePtr", 
						SpecialReg.newInstPtr ) );
				Code.load( IntType.type, SpecialReg.procValue, 
					new Displacement( decl.absoluteName(), SpecialReg.assemTemp ) );
				break;
			case Env.ENV_GLOBAL:
				Code.move( SpecialReg.zero, SpecialReg.newInstPtr );
				Code.loadImm( IntType.type, SpecialReg.procValue, 
					decl.absoluteName() + ".enter" );
				break;
			default:
				throw new Error( 
					"Invalid section of " + Decl.sectionText( decl.section() ) );
			}
		}
	}