public async Task ElTestoAsync()
{
var request = new SomeOperationRequest();
var validateApiKey = GetApiKey().ToValidation(new ValidationFailure("ApiKey", "API Key is missing in headers"));
var v = from v1 in validateApiKey
from v2 in Validate(request)
select v1 + v2;
var appCode = from key in v.ToOption()
from code in GetAppCode(key)
select code;
TryAsync <Result <SomeOperationResult> > bloo = from req in TryAsync(request)
from code in appCode.ToTryAsync()
select StartPaymentAsync(req, code);
string message = await bloo.Match(
Succ : tryRes => tryRes.Match(
Succ: payRes => $"Payment succeeded! PaymentID = {payRes.PaymentId}",
Fail: ex => ex.Message),
Fail : ex => ex.Message);
message.Should().Contain("42");
}
public void ElTesto()
{
var request = new SomeOperationRequest();
var validateApiKey = GetApiKey().ToValidation(new ValidationFailure("ApiKey", "API Key is missing in headers"));
/* This will create validation on Option<string>. ApiKey will be valid only when present. */
Validation <ValidationFailure, string> v = from v1 in validateApiKey
from v2 in Validate(request)
select v1 + v2;
/* Alternativly, we can do this way */
//var v_alt = (apiKey, Validate(request)).Apply((_, req) => req);
/* C# evaluates functions one-by-one. If one failes, the rest is omitted as we haven't got all required variables (v1 and v2) to complete the last statement */
/* All of the above is the great use example of monad being aplicative structure */
Option <string> appCode = from key in v.ToOption()
from code in GetAppCode(key)
select code;
/* Here we go again. Monad being applicative.
* Note we have to transform Validation to Option.
* We might miss something so.
* Maybe we should consider side-effects?
*/
Option <Result <SomeOperationResult> > mPaymentResult = (from code in appCode.ToTryOption()
from req in TryOption(request)
select StartPayment(req, code)).ToOption();
string result = match(mPaymentResult,
Some: mResult => mResult.Match(
Succ: res => $"Success! Payment ID = {res.PaymentId}",
Fail: ex => ex.Message),
None: () => "Invalid requqest.");
/* I guess we could do some more work here to make it more elegant, but I have enough.
* It kind of makes sense. We can get result only in if the validation passes and we have all required parameters.
* So we have to match first if we got any result and then if the result is Ok or Exception.
* We could still do it */
}
Result <SomeOperationResult> StartPayment(SomeOperationRequest request, string appCode) => new Result <SomeOperationResult>(new SomeOperationResult());
Task <Result <SomeOperationResult> > StartPaymentAsync(SomeOperationRequest request, string appCode) => Task.FromResult(new Result <SomeOperationResult>(new SomeOperationResult()
{
}));
/**
* Based on:
* https://github.com/louthy/language-ext/issues/313
*/
Validation <ValidationFailure, SomeOperationRequest> Validate(SomeOperationRequest request) => Validation <ValidationFailure, SomeOperationRequest> .Success(request);
