Add Conversion.into method

[odersky]

Small upgrade to make conversions easier to use explicitly.

[SethTisue]

was as considered as the method name? (I've lost track of as's status a keyword or soft keyword, and in how many places it's used...)

[odersky]

I am also not sure what's the best name. I have the feeling that as is already used quite a lot for specific conversions. I originally was thinking of inject, that's another possibility. into comes from Rust.

One consideration is that the name should work well with and without a type parameter. Compare:

xs.into          xs.as         xs.inject
xs.into[C]       xs.as[C]      xs.inject[C]

I have the impression inject works best without a type parameter, into is sort of OK, but as is taking it too far.

[SethTisue]

how about convert or converted?

[odersky]

convert would be the most obvious choice. That's often the best one, I agree.

[soronpo]

Maybe convertTo[T] will be a little bit more clear, although more verbose.

[rjolly]

@soronpo It doesn't work without the type parameter.

[rjolly]

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