[Feature Request] "Extended argument list"

["Soni L." <fakedme@...>]

Lua has multiple returns, but no way to use them inline with a function 
call. I was wondering if something like these could be added:

First idea: `f([3]pairs(t), 1, 2, 3)`;

- +This syntax is currently illegal, so it wouldn't break old programs.
- +The `[3]` clearly indicates how many return values to transpose into 
arguments.
- +Can limit varargs: with `f([2]pairs(t))`, `f` would only see the 
first 2 values of the `pairs(t)` call, dropping the 3rd.
- -Makes it feel like you can use `f([x]pairs(t))` (variable x) when in 
fact you can't.

Second idea: `f(pairs(t),,, 1, 2, 3)`;

- +This syntax is also illegal, so it also wouldn't break old programs.
- +While not obvious at first, the number of commas after the function 
call indicate how many return values to transpose into arguments.
    - Commas at the end of the call would still be illegal, this has 
the caveat of not being able to limit varargs.
    - Could be made so a single comma at the end means 2 arguments, as 
we can already use `(f())` to limit the results to a single value. The 
caveat is that commas at the end would mean ONE LESS than the number of 
arguments.
- ?This conflicts with the "implicit nil" patch, as the implicit nil 
patch makes `f(pairs(t),,,1)` become `f(pairs(t),nil,nil,1)`.
    - HOWEVER, this is more of an extension to the "implicit nil" 
patch: the code `f(t,,,1)`, would become `f(t,nil,nil,1)`.
- -(Very) Prone to "silent" typos.

The former syntax is better than the latter (3 positive points and 1 
negative for the former, 2 positive and 1 negative for the latter), 
altho I expect more people to like the latter simply because it's 
similar to implicit nil.

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