Validation <Error, BookTransfer> Validate(BookTransfer cmd) //=> ValidateBic(cmd) //.Bind(ValidateDate); /// This uses the | operator as a disjunction computation. If any items are /// Failed then the errors are collected and returned. If they all pass then /// the Success value from the first item is propagated. This only works when /// all the operands are of the same type and you only care about the first /// success value. => ValidateBic(cmd) | ValidateDate(cmd);
public void BookTransfer(BookTransfer cmd)
=> Handle(cmd).Match(
Fail: BadRequest, // Validation failed
Succ: result =>
{
result.Match(
Fail: OnFaulted, // Exception
Succ: u => OnSuccess()); // everything is OK
});
// Validation and Try are both examples of specialized Either
static void Main(string[] args)
{
var controller = new BookTransferController();
BookTransfer b1 = new BookTransfer
{
Bic = "1234",
Date = new DateTime(2019, 1, 1)
};
BookTransfer b2 = new BookTransfer
{
Bic = "1234568",
Date = new DateTime(2018, 1, 1)
};
controller.BookTransfer(b1);
controller.BookTransfer(b2);
}
Try <Unit> Save(BookTransfer transfer) => () =>
{
// Do some saving that could throw
return(unit);
};
Validation <Error, BookTransfer> ValidateDate(BookTransfer cmd)
// not pure but that's not the point
=> cmd.Date.Date <= DateTime.Now.Date
? Success <Error, BookTransfer>(cmd)
: Fail <Error, BookTransfer>(Error.New("Invalid date"));
Validation <Error, BookTransfer> ValidateBic(BookTransfer cmd)
=> cmd.Bic.Length > 5
? Success <Error, BookTransfer>(cmd)
: Fail <Error, BookTransfer>(Error.New("Invalid Bic"));
Validation <Error, Try <Unit> > Handle(BookTransfer cmd) => Validate(cmd).Map(Save);