Switch Expression Syntax with Block

[TonyValenti]

Hi All,
How do I do the following in a switch expression?

var Value = input switch {
  0 => 0,
 //How do I do this part?
 _ => {
    var r = 1;
    return r;
  }
};

Thanks so much!

[spydacarnage]

You can't, basically. If you just want to return 1, you can just write _ => 1 If you want to set the variable r as well as Value, but only if input isn't 0, you can't. Even if that was valid, r would only have scope within the block, and wouldn't carry on past the switch expression.

…

On Fri, 15 Nov 2019, 14:15 Tony Valenti, ***@***.***> wrote: Hi All, How do I do the following in a switch expression? var Value = input switch { 0 => 0, //How do I do this part? _ => { var r = 1; return r; } }; Thanks so much! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2964?email_source=notifications&email_token=ADIEDQJGWTRQM3A4RC6TXVDQT2VG7A5CNFSM4JN3LRAKYY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4HZT374A>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADIEDQJLR3WWBSRRC4OHIBDQT2VG7ANCNFSM4JN3LRAA> .

[TonyValenti]

Interesting! Based on the => syntax, I really perceived that what was on the right hand was an anonymous function which would allow block style syntax. From what I'm hearing, that is not correct though.

Am I right?

[spydacarnage]

No, you're not allowed blocks; only simple expressions. If you need to do some calculation work and then return a single value, you can create a local function and use that as the expression to return, but that still wouldn't be able to set a second variable.

…

On Fri, 15 Nov 2019, 15:44 Tony Valenti, ***@***.***> wrote: Interesting! Based on the => syntax, I really perceived that what was on the right hand was an anonymous function which would allow block style syntax. From what I'm hearing, that is not correct though. Am I right? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#2964?email_source=notifications&email_token=ADIEDQK4DZ5B4BE4FI3ET63QT27U3A5CNFSM4JN3LRAKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEEF2HMA#issuecomment-554410928>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADIEDQLAKJZWDIKCXWN2KH3QT27U3ANCNFSM4JN3LRAA> .

[HaloFour]

There are some proposals to explore allowing multiple statements to act as an expression:

#377

[gafter]

Either #377 or define a local function and call it.

[YairHalberstadt]

Closing as championed at #3037