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> why would a C++ successor language use `fn main()` instead of using C/C++ style `int main()`

Apparently easier and faster parsing. Most modern language have arrived at the `fn bla(arg: ArgType): ResultType` form and I don't think they made that decision for purely aesthetical reasons.

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> Most modern language have arrived at the `fn bla(arg: ArgType): ResultType` form and I don't think they made that decision for purely aesthetical reasons.

Not just modern, it's older than you think. Pascal function definition is `function bla(arg: ArgType): ResultType;`

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