C#•4w ago

Is it possible to use pattern matching here?

I want smth like this:

var isInbound = entity.LegData!.Location.LatestArrivalStationIataCode == "SVO";
var isOutbound = entity.LegData!.Location.LatestDepartureStationIataCode == "SVO";

return new PresentationModel
{
     Terminal = 
         isInbound => entity.LegData!.Location.ArrivalTerminal
         isOutbound => entity.LegData!.Location.DepartureTerminal
}

var isInbound = entity.LegData!.Location.LatestArrivalStationIataCode == "SVO";
var isOutbound = entity.LegData!.Location.LatestDepartureStationIataCode == "SVO";

return new PresentationModel
{
     Terminal = 
         isInbound => entity.LegData!.Location.ArrivalTerminal
         isOutbound => entity.LegData!.Location.DepartureTerminal
}

5 Replies

SWEETPONYOP•4w ago

var terminal = (isInbound, isOutbound) switch
{
     (false, true) => "Inbound",
     (true, false) => "Outbound",
     _ => ""
};

var terminal = (isInbound, isOutbound) switch
{
     (false, true) => "Inbound",
     (true, false) => "Outbound",
     _ => ""
};

i know this but it looks ugly

Angius•4w ago

I was about to propose exactly that lol

SWEETPONYOP•4w ago

i was faster 🙂

FestivalDelGelato•4w ago

you could add names, like

(isInbound: false, isOutbound: true) => ...,
(isInbound: true, isOutbound: false) => ...,
_ => oopsie

(isInbound: false, isOutbound: true) => ...,
(isInbound: true, isOutbound: false) => ...,
_ => oopsie

to me that helps it would be great if you could assign constants like

const (bool, bool) Inbound = (true, false);
var terminal = (isInbound, isOutbound) switch {
    Inbound => "Inbound",
    ...
};

const (bool, bool) Inbound = (true, false);
var terminal = (isInbound, isOutbound) switch {
    Inbound => "Inbound",
    ...
};

but you can't bu you could 'parse' it, although this starts to be too much for me (maybe) or you can wait for discriminated unions (sarcasm)

SleepWellPupper•4w ago

Here's another pattern:

return new PresentationModel
{
  Terminal = entity.LegData?.Location switch
  {
    { LatestArrivalStationIataCode: "SVO", LatestDepartureStationIataCode: not "SVO" } arrivalLocation => arrivalLocation.ArrivalTerminal,
    { LatestArrivalStationIataCode: not "SVO", LatestDepartureStationIataCode: "SVO" } departureLocation => departureLocation.DepartureTerminal,
    _ => throw new InvalidOperationException("no location provided or invalid station codes set")
  }
};

return new PresentationModel
{
  Terminal = entity.LegData?.Location switch
  {
    { LatestArrivalStationIataCode: "SVO", LatestDepartureStationIataCode: not "SVO" } arrivalLocation => arrivalLocation.ArrivalTerminal,
    { LatestArrivalStationIataCode: not "SVO", LatestDepartureStationIataCode: "SVO" } departureLocation => departureLocation.DepartureTerminal,
    _ => throw new InvalidOperationException("no location provided or invalid station codes set")
  }
};

Could use some terseness with the variable names I suppose. Note that for this one to work, the "SVO" string needs to be a constant.

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Programming

Is it possible to use pattern matching here?

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