package node.exprNode.prefixNode;
import node.*;
import node.exprNode.*;
import node.exprNode.variableNode.*;
import env.*;
import type.*;
import type.basicType.*;
import runEnv.*;
import runEnv.basicValue.*;

public class PreIncNode extends PrefixVarNode {

	public PreIncNode( VariableNode right ) {
		super( right );
		operator = "++";
		}

	public Type checkType() {
		Type rightType = right.checkType();
		if ( ! right.addressable() )
			error( "Operand for ++ not addressable" );
		if ( ! ( rightType instanceof IntType ) 
			&& ! ( rightType instanceof CharType ) )
			error( "Operand of ++ operator must be an int or char" );
		type = rightType;
		return type;
		}
		
	public RunValue eval( RunEnv runEnv ) {
		RunAddress rightData = right.evalAddress( runEnv );
		RunValue rightValue = rightData.getValue();
		if ( type instanceof IntType )
			rightData.setValue( new IntValue( rightValue.intValue() + 1 ) );
		else
			rightData.setValue( new CharValue( ( char ) ( rightValue.charValue() + 1 ) ) );
		return rightData.getValue();
		}

	}