public override object Exec(StringType firstOperand, object arg)
{
// * String WriteType and bounded type variables
if (TypeExpression.As <StringType>(this.secondOperand) != null)
{
return(0);
}
// * WriteType variable
TypeVariable typeVariable = this.secondOperand as TypeVariable;
if (typeVariable != null && typeVariable.Substitution == null)
{
// * A free variable is complete promotion
return(0);
}
// * Union type
UnionType unionType = TypeExpression.As <UnionType>(this.secondOperand);
if (unionType != null)
{
return(unionType.SuperType(firstOperand));
}
// * Field type and bounded type variable
FieldType fieldType = TypeExpression.As <FieldType>(this.secondOperand);
if (fieldType != null)
{
return(firstOperand.AcceptOperation(new PromotionLevelOperation(fieldType.FieldTypeExpression), arg));
}
// * Use the BCL object oriented approach
return(firstOperand.AsClassType().AcceptOperation(this, arg));
}
public override object Exec(StringType operand, object arg)
{
if (this.union.Count == 1)
{
return(null);
}
string notThisType = this.codeGenerator.NewLabel;
string endLabel = this.codeGenerator.NewLabel;
operand.AcceptOperation(new CGRuntimeIsInstructionOperation <T>(this.indent, this.codeGenerator), arg);
this.codeGenerator.brfalse(this.indent, notThisType);
operand.AcceptOperation(new CGRuntimeFreshTEPromotionOperation <T>(this.indent, this.codeGenerator), arg);
this.codeGenerator.br(this.indent, endLabel);
this.codeGenerator.WriteLabel(this.indent, notThisType);
// As the expected type is an String, we must call its ToString method
this.codeGenerator.CallVirt(this.indent, "instance", "string", "[mscorlib]System.Object", "ToString", null);
this.codeGenerator.WriteLabel(this.indent, endLabel);
return(null);
}
public override object Exec(StringType firstTypeExpression, object arg)
{
return(this.node.Operator == ArithmeticOperator.Plus ? StringType.Instance : firstTypeExpression.AcceptOperation(new MajorTypeOperation(this.secondTypeExpression), arg));
}
