[SUGGESTION] Removing special handling of return value of main function

[equeim]

Currently Cpp2 allows this code:

main: () -> int = {
    std::cout << "Hello \n";
}

I think this code is problematic because it says main function returns an int but it doesn't actually do this. It's especially bad for beginners since one of the first things you would have to explain is why it's allowed here and not in any other place, instead of more substantial things.

Instead I propose allowing to declare main function without return value (and disallowing previous example if it doesn't have return statement):

main: () = {
    std::cout << "Hello \n";
}

It will generate "auto main() -> int" that will return 0.
This way people who start to learn Cpp2 won't immediately ask "why it doesn't return int" (maybe). And the topic of special properties of main function and what forms it can take can be taught later.

[MichaelCook]

Only loosely related to this issue, but cpp2 could also easily allow other variants for main's signature, such as:

main: (std::span<char*> args) = {

[SebastianTroy]

Why stop there, span<string_view>? On 10 February 2023 13:02:07 Michael Cook ***@***.***> wrote: Only loosely related to this issue, but cpp2 could also easily allow other variants for main's signature, such as: main: (std::span<char*> args) = { — Reply to this email directly, view it on GitHub<#254 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AALUZQKMZPYYEY2T5UQZGOLWWY34ZANCNFSM6AAAAAAUWRZYMA>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[filipsajdak]

@MichaelCook & @SebastianTroy it was already discussed here: #63 (comment) and here #45 (comment)

[equeim]

I think this suggestion would be easier to implement than changing main's arguments. You already can't declare void main() in C++ so it won't conflict with anything. It's just a simple transformation of return type and possibly an addition of return 0; (though it can be omitted since C++ allows it).

[hsutter]

Limiting the discussion to the return type: Yes, currently all named functions default to returning -> void, and I've had an itch in the back of my mind to allow that to work for main too. Done... commit coming...

(I do it by just emitting Cpp2 -> int anyway under the covers. But in Cpp2 it's still truly a -> void default, because if you use that default you can't write return statements in the Cpp2 main body. Even though we emit -> int to Cpp1 to keep today's compilers happy.)

Thanks!