Language Feature?

[gafter]

@TheXenocide commented on Thu Mar 14 2019

I'm not sure what I would call this particular type of syntax sugar, but as I was reading through some source recently I wondered if there wasn't a readable way to simplify the following commonly occurring pattern? (Note: this is from some older sample source; I updated it here to use out string value already, where it was previously using string value; on the preceding line)

return Items.TryGetValue(RedirectUriKey, out string value) ? value : null;

Surely it's not the most important feature request, but I figured it wouldn't hurt to ask. Maybe something like

Items.TryGetValue(RedirectUriKey, return string value);

Allowing return to be used in place of out or ref (possibly even optimizing around allocation behavior? I'm not sure of the internals involved here). I honestly haven't thought super deeply about this so feel free to shoot it down, but it was a thought I figured I'd share.

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@YairHalberstadt commented on Thu Mar 14 2019

This looks like it would be more appropriate for the csharplang repo, where requests for language changes are taken.

Also, if you're not sure of a suitable syntax, you might want to discuss your ideas on www.gitter.im/dotnet/csharplang first.

[HaloFour]

You could just do:

Items.TryGetValue(RedirectUriKey, out var value);
return value;

Ignoring the return value. The out parameter is guaranteed to be assigned either way, and while you should confirm with the documentation generally Try* methods return the default value for that type if the action fails.

[TheXenocide]

True, and this is generally what I do (the sample above is actually from an MS AuthenticationProperties class related to their claims authentication abstraction). I don't suppose it would save much in that context, unless there's some sort of return register optimization to be had, which could probably be performed during compile-time optimization (if there was an optimization to be had here anyway) without the syntax sugar mentioned above.

[TheXenocide]

Also, thanks for the pointers @YairHalberstadt

[Thaina]

Normally I do

return Items.TryGetValue(RedirectUriKey, out var value) ? value : null;

I don't like your syntax. It hide the return in the middle of the line